Cleaned out the barn and found an old tube radio and record player there. I'd like to get it working again.
did some background reading, so I know not to plug it in, until I can replace the caps. The tubes look good on first sight- not obviously cracked, and the getter coating is still shiny. It's not an AA5 (has a power transformer) and appears to have seven tubes on first count. This thing also has two output transformers for the speakers.

Hopefully some folks here can help me out with advice for the restoration-
It's a "Fleetwood Stereo Hi-Fi", model 4068. I can't find ANY info or schematics online (tried justradios, nostalgiaair), and a service manual would be wonderful- the dial string is broken and I'm looking for that particular diagram.

Does anyone know anything about this set, or where to get schematics?

Also, someone slapped a coat of ugly brown paint on top, which is now flaking off- any idea what the original finish may have been? I'm tempted to strip and varnish it; the wood underneath looks like a nice fine-grained sort.

Finally, anyone know about the turntable on this thing? I had a look at the cartridge, and it doesn't seem to have a user replaceable needle- was there ever such a thing?

TIA,
VintagePC

Well, I'm not familiar with "Fleetwood" - may have been a store brand built by someone else. I'm sure if you posted some pictures it would help folks ID the set.

Fleetwood was a Canadian brand based in Montreal which sold both its own
designs and rebranded units either Canadian or European made. Are you
in Canada? Will look up your model number in my (incomplete) collection of
Radio College of Canada manuals.

Correct you are! Inside label does indeed say Montreal QC on it, and I'll gladly post some pics once I finish removing the (literal) mouse's nest of fiberglass insulation that was stuffed between the chassis and the cabinet... I think it was the little buggers that gnawed through the tuning cord too.

All in all, the cabinet, grille cloth, and set are in pretty good condition- the room we stored it in was dry- There were some books from the 50s-70s in the same room which were still in near-perfect condition- no mold or mildew on them.

As given by my username, I can sniff out a C64 at 50 paces, but have no experience with old radio equipment :)

I'll get some snaps of the tube layout diagram too, as it may be of some help.

Cheers, and many thanks,
VintagePC

Welcome aboard! Unfortunately, I did not find your model number, but by all means
do try this link:

http://www.justradios.com/schematics.html

Even though they don't mention Fleetwood in their list of makes, they might
very well have what you need. Moving from VLSI silicon to old tube radios should
be a rewarding experience, I will be glad to help you with advice whenever
possible, and I trust many others will be doing the same. By the way,
videokarma is the little brother of audiokarma (was actually part of it until last
year), which is a much bigger thing in terms of audience. I spend time on
both, and you could register with the same user name if you wish. Good luck
with all your projects!

P.S.: actually, they do mention Fleetwood in the longer list down the page.

Alas, I already tried JustRadios- they don't have any info on the unit.

Looks like we'll be forging ahead blindly... but it's possible I've messed up the model number- it is from memory, and I'm sure of the digits, and that the second digit is a zero (and the first is NOT an 8); it could very well be 6048, 6084 or 4086- though I doubt it was either of the latter two.

I've already registered with AK, they were the ones to refer me here, b/c of the specific "antique radios" section. I'll probably end up lurking in their turntable forums when I get to that part of the restoration. (and I'll be here some more when I finally get around to fixing a wonky Commodore 1701 monitor I've pack-ratted away)

Anyhoo, I'll double check the model number and get some shots of the set this weekend- real life calls and I have a conference to attend, which eats my spare time for a few days.

Also thanks for the welcome and assistance offer- it's what I love about the Internet; bringing people, information, and hobbies together!

VintagePC

Honestly, you may get more guidance here on an old turntable. The AK side tends to be more interested in the "audiophile" stuff. Anything tracking a two grams or more is handled like the plague over there (generally.) :)

Heh... right now it's tracking nothing- The tone arm is off of the control tower because someone swiped the spring from it. :sigh:
Got plenty of springs in my spares so I should be able to find something for it.

Any ideas on needle-less cartridges? There looks to be a permanently fixed copper "fin" with a small point attached to the end.

The mechanisms still seem to operate smoothly, so apart from needing a little lube and TLC, it looks like it will be all right. Might need to oil the motor bearings though. The turntable has a 4-way selector- 78, 45, 30, and 15 rpm...
The other selector is labelled "Off", something indicating play, and "Rej", which I assume advances the record (it has one of those arms that lets you load more than one record at once.

It plugs in to a special socket on the chassis- presumably switched and activated by the knob to change from phono to radio.

There's also another (internal) socket like it labelled "TV only" or something ?!?? Any idea where/why/what that would be for? Set with a built-in TV might be possible- there was more than enough room in the cabinet for a small tube.

Cheers,
VintagePC

The little point at the end of the metal fin is actually the needle of this ceramic
cartridge. Do post some pictures soon if possible! Bye for now.

Some preliminary snapshots I took this morning-
I apologize for the fuzziness, as the lighting is poor.

No pics of the turntable yet, since the chassis is currently sitting on the access door.

Pics are here: (large files, so to save bandwidth, they are on my own web host)

http://vintagepc.co.nr/radio/

Also, link to the AudioKarma thread: some interesting info there too:

http://www.audiokarma.org/forums/showthread.php?p=3694720

Hello again,

Here is a schematic that does include single-ended 6AQ5 outputs,
even though the model number is no exact match. Hope this may
help a bit, all questions welcome. By the way, some of your pictures
would be better if you held the camera steady, low light is adequate
but exposure too long to yield clear pictures by just holding the
camera in the hands. Good luck!

P.S.: the schematic is from RCC Supplement No. 59, dated 1962.

From the looks of your chassis, it would appear that the radio is AM only,
is that the case?

Hmmm.... Looks like it might be close, but there are some pretty big differences- almost certain my set does not have FM, nor does it have as many tubes.

I'll get some shots of the chassis underside tomorrow when I've finished cleaning it up.

Edit: If that is indeed the case, I'll have to see what I can get for AM here... If there's nothing good, looks like I'll be building one of these:

http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html

Hello again,

This should be much closer. Be careful when cleaning around fragile parts
such as the variable capacitor (plates are easy to bend, just leave them
meshed) and the oscillator coil L2 under the chassis.

The TV outlet is just an unswitched utility outlet with a fancy label!

I think we have a winner- that layout is a perfect match for what is stapled to the inside of the cabinet... (though I think my set uses something other than 12AX7s... I _think_ 6AUsomethings... is that possible?
Does the AM-only offer any indication as to year, or no?


VintagePC

The year would be also 1962 (RCC supplement No. 58), in fact the two schematics
I posted may have been on the market at the same time. Many areas in Canada
at the time had no FM at all, so a cheaper AM-only chassis was a good selling
argument.

If I may add a few comments, I would say that this is a fairly good introductory
project to tube radio restoration: the radio part of this unit is as simple as it
gets while remaining useable for listening, and the amplifier should be reasonably
good (with negative feedback as it is), although you should not expect tremendous
bass from such small output transformers. The negative feedback is effected
by resistors R40 and R41.

If you have a working AM radio (a car radio would be best for this), do some
listening after sunset (or before sunrise), you should get a number of stations.

You may be right in assuming that the audio stages before the outputs are
somewhat different from the schematic, this will have to be confirmed. Note
that in the schematic, each 12AX7 is part of both channels, so if one
of these tubes is shot, no sound will come out.

I look forward to the under chassis pictures. Bye for now.

interesting... very interesting indeed- the only reason the set has stereo then, is for the phono. (though since the pickup is ceramic, I'll probably look in to getting a magnetic one with a pre-amp... don't want to damage those vynils....

A quick google shows that the 6AU6 seems to be half of a 12AX7...

Also, any chance you've got a dial stringing guide or just a "common" stringing method to try? I know it's usually 2 turns around the tuning cap and 3 around the tuning knob... unless there's a piece of dial string missing that should just about do it.

Thanks!

You got it wrong here: a 6AU6 is a pentode, while a 12AX7 is a dual triode.
One half of a 12AX7 would be a 6AV6, which also includes a pair of diodes.

Also, a 12AX7 has a 9-pin socket, while a 6AV6 would have a 7-pin socket.
So just pull those two tubes in front of the 6AQ5s and count the holes...

Sorry I can't help you with the stringing, there are just two many different
ways it is done. Unfortunately, the diagram is not shown for this model in
my service manual, but when you can post a clear front view of the front
of the chassis, showing the tuning shaft, the pulley on the variable
capacitor, and the pointer on the dial, maybe someone else could provide help.

Regards.

P.S.: I looked at your picture again, and those two tubes do indeed look
like 6AU6s! It is indeed possible to design a single pentode audio stage to drive
a beam power tube, but that would be somewhat different from the schematic.

Hello again,

I did a thorough search of the Fleetwood data in my collection of RCC
manuals, and I believe this will be the closest we will get to what you
actually have on hand. Somewhat simpler amplifiers, but still an
interesting project. This is from vol. 53, 1961.

right you are- I mis-read the post; that user was also misinformed and asked whether a 12AX7 could be replaced with two 6AU6s. (Later corrected as 6AV6s)

's what I get for not reading the whole thread.

I'm almost certain the tube layout diagram is the same now- I'll get out the tripod and get you guys some less hasty (and well lit) pictures tomorrow, including the record player. I hope to log the restoration and add it to my web site for everyone to view.

I'll be keeping this thread alive as I go through various stages of restoration, asking for advice and posting pics- I'll start by giving the tubes a thorough inspection (and check the filaments with a DMM) before I go any further. They all look to be original Fleetwoods- fingers crossed!

I plan on restuffing all of the caps, just for the hell of it; I love old hardware and authenticity- . One of my Commodore 64 still has the "Warranty sealed" sticker on it and is in near pristine shape.

We have exactly one AM radio station left near enough that I should be able to receive... classic and modern country; at least it's not talk.

What are the chances that the chassis is cadmium coated? It's not oxidized at all (and you can see rust around the power cord)- my bet is steel.

I'll also have to replace the line cord- the prongs on the existing one are more crooked than a 419 scam :D

Many thanks for all the help so far and in the future - "May your tubes always light!"

VintagePC (and radio!)

OK, just finished cleaning out the bottom of the chassis and got a good look at everything:

- It is an AM setup. Oddly, the dial has three settings: Phono, Radio, and Stereo.

- There was a sticker on the chassis that said "2053" so we have the right schematic. 4068 is probably the cabinet/overall design.

- All tube filaments check good with a DMM.

- I'll get some decent pics as soon as my camera batteries finish charging.

- Components look almost new! The caps say "Plasti-seal" and don't appear to be covered in wax... rather a heat-sealed plastic. Thoughts?

- Speaker cones are in pristine shape... surprised the mice didn't get to them!

- Phono cartridge is invertible... for slow/fast records.

VintagePC

Hi, looks like an interesting project. Just a couple of notes: the function switch probably connects the cartridge left/right outputs together in "phono" position: there were still plenty of monaural records around in 1962, as stereophonic records only came out in 1958, and for a number of years both stereo and mono records of the same issue were sold, the mono being a little cheaper. A stereo record played with a mono cartridge would be damaged.

As to your dial cord, if you need new cord, look in your fishing tackle box, or that of a buddy, for some of that woven line. It's strong and should work fine. Not the monofilament line.

More pictures posted at the above link. (#s 39-46)

A couple of things to note:

- Sorry the second chassis shot is fuzzy- It looked sharp on the camera screen. The camera must have focused on a shiny bit.

- The cabinet appears to be solid oak (!!) and some crappy paint-on plastic veneer. They didn't prime it, so the veneer is peeling off everywhere. (and beyond recovery). I plan to strip it with a cabinet scraper and use some varathane 1000 on it.

- I've started cleaning and oiling the turntable (oil for motor-driven parts, lithium grease for mechanical linkages etc.). You can see this in some of the shots. The guy that painted the cabinet couldn't even be bothered to take care- there's brown paint everywhere (including on the knobs!)

- Can someone refer me to some info on the cartridge on the turntables? It is a BSR turntable. More specifically, which of the two stylii to use for what.

- Some of the detail paint is in poor shape- the gold lettering on the turntable controls, and also the "fleetwood" logo on the tubes (but not the other markings) wipes off at the slightest touch. Not a biggie, but I think at least something should be done about the control lettering.

Thanks for the dial stringing info- I was aware of using fishing line; has anyone had success with waxed dental floss as a temporary fix?

Microgroove or LP stylus is for 45s, 33 LPs.

Standard or 78 stylus is for 78 RPM shellac discs (manufactured until the late
fifties in Canada, early fifties most everywhere else).

Will have a look at your pictures, I am quite busy this week. Bye for now!

Thanks for the info- I'll have to look in to it some more, since the little flip-switch cover is missing; there's no indication which tip is what.

(Time to take out the microscope and look at the tips... which would also show how worn they are!)

It seems the turntable is a BSR UA-14. Some googling reveals that:
a) these typically had TC8M cartridges, and
b) if that is the case, we have a crystal cartridge on our hands.

As such, it is very likely that the crystal is dead; I might well look in to replacing the cartridge with a magnetic one to save wear on the discs. (I know I'd need a preamp, re-balance the tone arm, yada yada yada...) Ugh, not something I want to think about now.

What's more, the TC8M appears to be MONO! This would make sense, since there are 4 leads running through the tone arm, but one of them is not connected to anything... seems the "stereo" in this set was nothing more than snake oil, unless the audio outputs share a common ground. Probably sold as "stereo capable" or some such, requiring an after-market upgrade.

Edit: Yup, crystal:
http://www.hupse.eu/radio/reproducers/TC8S.htm

You could sub a ceramic cart of the same output voltage and not worry about building a preamp circuit, although that's not particularly hard to do. Personally, on a unit like this where I would be playing old records (especially 78's) I'd stick with ceramic because of the many different record equalizations in use until the late 1950's.

If you need needles or a new cartridge, the folks at Canadian Astatic (I have no connection, just have bought from them) are very helpful. You can send the model number of your set and all the numbers off the cartridge and they can match it from their vast store of information and parts. Upgrading to a magnetic (with preamp) might be possible, but depending on the capabilities of the changer, tracking at as low a force that you'd like might not work. Changers generally take more tracking force than manual turntables because they are dragging around all of that mechanical baggage to operate the changing mechanism.

http://www.canadianastatic.com/

Errr... wha?

I thought the tracking force was the amount of pressure the tone arm has on the LP.

What has that to do with the force of the motor driving the mechanics? (We have a nice Dual w/ Shure mag pickup in the main setup, and it has a changer spindle too).

Let me go get some detailed snaps and post them...

Edit: Styli are TC8G and TC8RS... Apart from some dust, they still look to be in good shape (pics coming...)

Sorry if I confused with motor power: what I was getting at has nothing to do with that. The tone arm in a changer does not have the complete freedom of lateral movement like a fully manual turntable. There are mechanical connections under the changer base from the arm to various parts of the mechanism to trigger the various change functions. The result is the arm has more work to do than just track and play the groove and there's more resistance to lateral movement of the arm. The only force that moves the arm to the center of the record is provided by the needle being held in the groove. The resistance to lateral movement has to be overcome by more tracking force to hold the needle in the groove. Too little a force and the needle jumps out and won't track. The better changers (like your Dual) have more refined mechanisms and can go lower in tracking force. Do you know the tracking force of your Dual? I would suspect the changer in your Fleetwood would require a couple or three grams more to track successfully. Hope this didn't go on too long!! :boring:

Ah,that makes sense... I was thinking up/down and not left/right. I don't know the tracking force of the dual, but it is probably somewhere around 1-2 g, and crystals are ~6-8g.

I'll end up seeing if it works just for the heck of it... if not off to ceramicville :)
Can one test the cart using a DMM (or AMM) set to mV, or is the signal too unsteady?

Edit: Pics posted. #s 46-58. (Reminder: Here (http://vintagepc.co.nr/radio/))

I think they test cartridges using a standard record with a steady tone, maybe 400 cps. Music would be all over the place. The best test is to hook one up and "see if it works."

From the pictures, the changer could use being taken apart and all the old grease and dirt cleaned out and white lithium grease and light oil used sparingly, keeping any oil off the rubber idler wheel. The wheel and every part it bears on can be cleaned with alcohol for better traction.

Yep... working on that :)

I've already gone through the control tower and greased the sensing arm and linkages for the on-off switch. You can see a few shots (1042-1044) from when I started cleaning the control switch "plates"- they return to a light ivory white, and were nearly brown at first.

Someone did maintenance on it not too long ago. Many parts are still well-lubed and working smoothly (or the old grease hasn't dried out).

Next chance I get I'm going to pop off the motor and check that the bearings are still well oiled- if so, then I should be able to hook it up to something and get a signal (well, if the cart is still good). I also need to lube the speed selector mechanism; it feels a little chunky. The table itself glides smoothly, and I Li-greased up the changer gear under it to keep it quiet.

Does someone have _definite_ specs on the cartridge? It is a TC8S, with (as mentioned, TC8G and TC8RS styli). Some sites say stereo, some say TC8 was mono, etc. etc...

It seems to be wired for stereo, with one of the three pickup wires being a common ground (bridged at the terminal block under the turntable), with the other two going to the center pin of the phono plugs. Yet another site suggests that there was one wire for each needle... Very confusing.

Also: there's an adjustment screw at the top of the changer tower, under the tone arm (in the block that holds it to the shaft). What is this screw for (visible in lower left of image 1039- perhaps auto-return trip point adjustment)? I _will_ need to remove that spring assembly from the shaft at some point, how critical is it to get that back to that exact position?

With regards to the rest of the set: Once I finish the turntable, I'm going to re-stuff the electrolytic multi-cap. do I still need to do the others, because they seem to be plastic/metal sealed (and not wax/paper). There's a better chassis shot in the last bunch of photos.

I'll also be checking the resistors and replacing any that are out of spec so I can get them in with my order of caps.

Sorry for all the questions ;) I'm not experienced in this area at all, but I'm fascinated by this stuff and can't learn enough- there's something awe-inspiring about watching the intricacies of such mechanisms at work.

What kind of audio wiring do you find in the changer assembly? There should be
two shielded cables with a common ground, with the inner conductors connected
to the each of the live terminals (Left and Right) of the cartridge. The third
terminal on the cartridge should be connected to the common ground (shield) of
the cables.

Regarding capacitor replacements, at least the three interstage capacitors
should be replaced. If they are leaky at all, they will allow a positive bias
on the first grids of the 6AU6 or 6AQ5 tubes, which may kill them and other
components in short order. Those capacitors are C10, C14 and C19.
The DC voltage on the grids of these tubes (pin 1 for the 6AU6 and pin
7 for the 6AQ5) should be zero at all times, as they are connected to the
ground through the potentiometers and no grid current is normally flowing.
If you choose to go with the existing capacitors, at least do hook up a
DC voltmeter and check each of these voltages. Also, do not operate
the amplifier without a load connected to the speaker outputs. A 2 watt,
8 or 10 ohm resistor connected between the 8 ohm tap and ground of each
transformer would be fine if you don't want to hook up the speakers.
Good luck!

P.S.: Another tip - do not do any restoration work yet (except replacing big
capacitors such as C5/C6/C7 if you wish) in the tuner area, it is too easy
to disturb things there.

Hmmmm... the wiring is indeed as you describe (sorry if I wasn't clear).

- I took undergrad physics, so let's see if I learned anything:
The load is needed so that the back-EMF from an open transformer doesn't fry the output tubes, right? (and I should check those for opens/shorts too)

Thanks for the info on the caps. I'll have to look and see what I have in my parts bin; if I have to order, then I may as well get them all to get the most out of the shipping costs.

Slow going for a bit (some other stuff on the go) but I'll start a detailed HTML page soon.

VintagePC

Good place for caps, in case you don't know, is Just Radios, Canadian, very helpful folks.

http://www.justradios.com/

My preferred source is DigiKey (excellent customer service) but they've recently changed their shipping setup on the web site... so if I have to pay $20 for shipping (used to be flat-rate $8.00 except for oversize/heavy), I'll definitely go with JR.

My preferred source is DigiKey (excellent customer service) but they've recently changed their shipping setup on the web site... so if I have to pay $20 for shipping (used to be flat-rate $8.00 except for oversize/heavy), I'll definitely go with JR.

Digi-Key is fine for the latest SMT components and the like, but for
the kind of parts used in old radios, a supplier like justradios is
definitely recommended. I have bought a general purpose kit
of capacitors from them and was fully satisfied. Also, do a web
search with the keywords hamfest and the name of the nearest
large city. A hamfest is a kind of flea market organized by and
for amateur radio operators (hams), and all kinds of goodies related
to the old radio hobby can be found there. But maybe you already
know that from your old computer hobby...

Bye for now!

Good news: I repaired the dial string and it looks to work: I cut some strong cotton thread to the same length as the original, coated it in candle wax, and strung it up. The tuning knob now works, so all I'll need to do is give the needle a nudge if it is in the wrong spot.

Here's where things get difficult: I've noticed some differences between my set and the schematic, such as cap and resistor values. Perhaps it is based off the 2053 but with some revisions?

There's also some bad news- one side of the coil marked L2 appears to be frayed. any suggestions as to what I can do?

Thanks,
VintagePC

Can you post a clear close-up of the coil? I just ran into such a situation. The fix depends on how the coil is made. If you can check continuity with your ohmmeter it may be OK, though.

Sending you a PM.

Ok... quick updates:

- I have snaps of the coil, but they'll have to wait until Tuesday; large photos aren't dial-up friendly :no:

- I've been de-rusting the chassis... a couple of spots that I want to take care of before they get bigger.

- First tests of the LP deck: motor works and runs smoothly. A bit of a hiccup with the auto- shutoff not catching, but some Li-grease and a spring adjustment later, and all is well. Can't test cartridge yet, as the tone-arm hinge was broken. The epoxy is now curing. There's not much stress at that point, so it should hold.

- Working on a restore log... watch for it soon :)

Okay... two birds with one stone.
Here's the build log so far. There is a picture of the frayed coil as the last item on the page; you can click any of the images for a larger version.

Enjoy!

http://vintagepc.co.nr/site/index.php/stuff/radio/

Also, feel free to leave comments as to what you think of the site's layout/design. I've put some time in to revamping it and I'm happy with the result- simple, clean and elegant.
Hope you like it too!

I like your website with the built-in links and all. That coil got lunched, didn't it? Hard to tell but if it was just the outer wires, I'd make a careful drawing of the orientation of the coil in the set and where all the wires go, unsolder it, take it out, and try to scope which broken wires go with which ones. But this coil "looks" like it's beyond that.

One thing you could try, then, would be to carefully unwind the broken turns of the coil, keeping the wire, until you get to just one wire coming out of the good part of the coil. Then carefully scrape to bright copper and solder that wire to the broken pieces one after the other and wind back on as neatly as possible. It's important to wind in the same direction as the coil was originally wound. You won't be able to wind like the machine but that's OK. Have a candle going nearby and drip wax on the coil as required to keep it together. Reassemble and it might work. It might require the tuning cap trimmers readjusted to get it to track.

Another fix would be an oscillator coil out of a junked plastic table radio. Someone on the forum might have a junker that he could send you the coil from: I don't have one at present or I would.

If not, AES sells replacement oscillator coils. I don't know which of these would work in your set, but they're cheap and one of them would: I'd get both and tack them in and try them. Search "oscillator coil:" see the first two $1.95 coils on the page.

http://www.tubesandmore.com/

I like your website with the built-in links and all. That coil got lunched, didn't it? Hard to tell but if it was just the outer wires, I'd make a careful drawing of the orientation of the coil in the set and where all the wires go, unsolder it, take it out, and try to scope which broken wires go with which ones. But this coil "looks" like it's beyond that.


Thanks- glad you like it!
I wonder if it was the mice, or whether it was something else; there aren't any bite marks in the wax, so it looks more like careless handling or a scrape against a sharp edge.

I'll give the repair a try and see what happens. I think it looks worse than it is because of all the fluff that is present. If not, I may have a spare coil from a junked stereo set I can use- I've amassed quite the pile of spares over a few years; all manner of toroids, transformers, and so forth. We'll see what happens- Thanks for the link to AES.

There are two coils on the same core there... I take it one is for the oscillator, and the other is a "hum-bucking" coil?

Regarding the trimmer adjustment, what would that entail? I don't have extensive sophisticated tools on hand.

The oscillator coil consists of the whole L2 assembly, the two windings together.
Adjusting the trimmer is explained in the instructions with the schematic, but it
all boils down to a simple thing: making sure the stations are at the correct
frequencies on the dial.

By the way, it might be time to give the amplifier a try, feeding it with the line
output of a CD player or mp3 player. Adapters with RCA plugs that fit the
phono input are quite easily found. Bye for now.

Not to worry, I have plenty of RCA-outputting hardware at my disposal, not to mention some R2Rs :)

I've been holding off on ordering the caps etc. because I'm going to be very busy for the next three weeks- no time for projects such as this. (Hence I started with something simple like the turntable). After that, I should have plenty of free time to get in to my own projects, and then this will take off :) Thus, the original caps are still in place, and it's not quite ready for a bench-test yet...

The epoxy should be cured (>24h) by tonight, so I'm going to grab a test (read: not particularly important) 78 and take it out for a spin.

As electroking noted, both the coils shown as L2 are on that assembly, and the two lower ("cold") ends of the coils are connected together and to system ground. If substituting a different coil, determine the common terminal and connect the same as before. If the set won't oscillate (as determined by the set tuning broadly, maybe one station all over the dial), reverse the connections of one of the coils.

Main tuning cap alignment: tune in a station of known frequency near 1400 Khz. The trimmer on the smaller section of the tuning cap will move the station up or down the dial until it reads correctly on the dial scale. Then tune to a weak station around 1400 and peak reception with the trimmer on the larger section of the tuning cap.

Hello again,

The reason I suggested trying out the amplifier was to help you find something
stimulating to pursue the project: the amplifier will work even if the radio section
is not fixed. As long as the function switch is set to phono or stereo, the radio
section is not powered (except for the tube heaters). If you have to set this
project aside for sometime, I would suggest that you do some reading on the
principles of superheterodyne receivers (that just means a receiver with a
local oscillator and demodulation at a fixed carrier frequency called the Intermediate
Frequency). Examples of useful books include any old edition of the ARRL handbook,
good old textbooks such as the one by Terman (Electronic and Radio Engineering),
etc. Bye for now.

P.S.: testing with the turntable and an old 78 is fine too!

Well... game over for now :tears: The TC8S is indeed quite dead... there was crystal dust everywhere.

Looks like I'm on the hunt for a new cartridge. Any recommendations for a drop-in ceramic replacement (TC12H?) or how much I can expect to spend? (and possibly a good supplier in NL?)

Thanks!

Canadian Astatic. Send them your set model number, and all the numbers on your cartridge. They will have one that will work.

http://www.canadianastatic.com/

I've sent them an email and am waiting for a reply.

While googling, I came across this:

http://www.angelfire.com/electronic2/radiosean/tv/Cartridge-rebuild.htm

Anyone tried it before? Or will that hack only work well in a mono cartridge?
I have several piezo buzzers I've salvaged... and it's not as though they are expensive. Perhaps I'll give it a shot.

I've sent them an email and am waiting for a reply.

While googling, I came across this:

http://www.angelfire.com/electronic2/radiosean/tv/Cartridge-rebuild.htm

Anyone tried it before? Or will that hack only work well in a mono cartridge?
I have several piezo buzzers I've salvaged... and it's not as though they are expensive. Perhaps I'll give it a shot.

I would say don't bother with that, a good replacement cartridge should not
be that hard to find, and it will come with brand new styli. By the way
I looked at your site (thanks for the credit to me regarding the schematic!)
and I wonder why you concluded that the oscillator coil was shot.
Maybe it's obvious to you, but did you trace the connections to the
rest of the circuit to confirm that something was wrong? Good luck.

I would say don't bother with that, a good replacement cartridge should not
be that hard to find, and it will come with brand new styli. By the way
I looked at your site (thanks for the credit to me regarding the schematic!)
and I wonder why you concluded that the oscillator coil was shot.
Maybe it's obvious to you, but did you trace the connections to the
rest of the circuit to confirm that something was wrong? Good luck.

You're welcome- when the writeup is finished, anyone here who's contributed significantly will be credited :yes:

I figured as much... I'll have a look around to see what I can find locally in addition to AES; chances are a specialty electronics shop may have something.

Re Coil: There are several broken wires coming off the side (click the picture for a larger version, easier to see) and there is no continuity if I test the lower coil with a DMM.

I'm going to give Reece's suggestion a try as soon as I can get back to the project- I think it may be fixable with some care... it looks worse than it is.

Okay... Just in time :)
I dropped by a specialty electronics store and I managed to get his last ceramic pick-up for a good price.

I never heard back from Canadian Astatic, and the cost was less than they asked anyway.

So now I have a Philips GP-815, and I just have to figure out a way to mount it (which shouldn't be difficult- it comes with a small metal plate to clamp it securely; If I drill and tap the plate then I should be able to use the original mounting screw in the BSR tone arm.

Does anyone have detailed specs? All I can find is this page, which offers little help (except confirming that it is ceramic):
http://www.topkaufmunich.de/plaintext/systeme/philips/gp815gp815gp815tonabnehmersystemphilips.php

I would assume the standard tracking weight of around 6g would apply.

(Though I've heard it's better to be on the higher end of the range- which would be ~8g. I know too light will damage the record as the stylus skates around, but what sort of problems would you get with too much tracking weight?)

Okay... Just in time :)
I dropped by a specialty electronics store and I managed to get his last ceramic pick-up for a good price.


ok i can't imagine where you scored a ceramic cartridge in our city...i don't do vinyl,but i'm thinking it might be useful to know what business around here even sorta carries stuff like that...best guess's? Hamblins?maybe Peak?

Sorry, it's not in Canada, actually :)
This is in Europe- I've found the newer American Philips (Magnavox?) products to be nothing but crap, whereas here it's still decent quality and a respected brand.

As an FYI, the store is Technica B.V. in Nijmegen, NL.
They would probably still have some tubes on a back shelf or know where to get them, but I didn't think to ask (and trying to transport them by plane is asking for it!)- This guy is basically your local electronics shop for the hobbyist, all kinds of components and supplies.

Edit: I'd wager a store like that would do really well for the tinkerer in Halifax.. but you might try RAE electronics in Burnside. I usually order all my other stuff from Digi-Key, but if you'd like, I can ask around as I know a few people who support older electronics and might know where to get the stuff locally.

Sorry, it's not in Canada, actually :)
This is in Europe- I've found the newer American Philips (Magnavox?) products to be nothing but crap, whereas here it's still decent quality and a respected brand.

As an FYI, the store is Technica B.V. in Nijmegen, NL.
They would probably still have some tubes on a back shelf or know where to get them, but I didn't think to ask (and trying to transport them by plane is asking for it!)- This guy is basically your local electronics shop for the hobbyist, all kinds of components and supplies.

Edit: I'd wager a store like that would do really well for the tinkerer in Halifax.. but you might try RAE electronics in Burnside. I usually order all my other stuff from Digi-Key, but if you'd like, I can ask around as I know a few people who support older electronics and might know where to get the stuff locally.

oh ok,you referred to me as "a fellow Haligonian" in another thread,so i assumed you were local to me,...but you're living away perhaps?...i figured if you had found a place here that actually stocked a ceramic cart...that was a place i should know about!!

i haven't been into RAE in several years,it was usually a wasted stop unfortunately.they always seemed to put more emphasis on commercial/industrial concerns..alltho welcome,they're not really there for the individual in need of a few bucks in parts was always my impression...Jentronics also in Burnside is my store of choice these days...never had a bad experience,friendly,happy to offer advice and usually have what i need,or will order it in if not...found out on my last trip in that the guy on the counter also had experience in restoring radios...very helpful

oh ok,you referred to me as "a fellow Haligonian" in another thread,so i assumed you were local to me

Ordinarily, yes, but I'm visiting family at the moment :thmbsp:

II've heard of Jentronics, and I'll have to give them a look sometime.

Another decent place is Princess Auto; while they have mostly tools and car parts, they have miscellaneous electronics in the surplus section... great place for AC adapters and cheap cables, fans, etc- While I doubt they carry pickups, it couldn't hurt to give them a call.

I wonder if Halifax is just too small to support such a store- the major problem being supply. It seems to me that this "old" technology is just much more alive in Europe than in the Americas. (e.g. the video about the man making his own triodes- he's in France)

Okay, I'm back at it :).

Just for kicks, I asked the guy if he also had any dial cord or tubes... Negative on both counts, but I did win that bet :D

Anyway, I was able to mount the new cartridge, wire it up and set the tracking weight using a jury-rigged balance and a loonie (which is exactly 6g!).

However, doing a dry run, (nothing connected to the turntable), I can actually hear the sound on the record. It's not loud, and somewhat tinny (kind of like someone standing next to you with their earbuds cranked.)

The needle isn't skating, it is well seated in the groove.

I don't want to damage anything, so I stopped right away... More newbie questions:

- Is that normal, or too much/little tracking force?

-If not, could it be the stylus angle (and should it be 90 bang on, or more/less)?

Finally, I still have the TC8G and TC8S styli... Both look in good shape. Anyone want to buy them to fund my restoration? :scratch2: "Super macro" pics on request.

Many ceramic cartridges produce an audible acoustic signal if you bring your
ear close enough, no need to worry. Good to hear of you again!

Well, in that case, the turntable now works!

Back to the chassis... The oscillator got lunched all right. It's well beyond repair.... Off to source a replacement :)

Would it be an idea to re-build the coil? I've calculated the length of damaged wire to be 5m, and I have the same fine stuff on hand.

Could it work, or would the new specs be different enough to require adjusting the set anyway? (what I'm hoping to avoid)

Would it be an idea to re-build the coil? I've calculated the length of damaged wire to be 5m, and I have the same fine stuff on hand.

Could it work, or would the new specs be different enough to require adjusting the set anyway? (what I'm hoping to avoid)

It will require alignment of the trimmer on the oscillator section of
the variable capacitor, but that's no big deal. IF
alignment (the slugs in the IF transformers) should not be affected.
Rebuilding the coil on its original cardboard core will probably
yield better results than trying to fit a 'universal' replacement coil.
By the way, the exact number of turns matters more than the length
of wire, so try to stay as close to original specs as you can. Also the
wire must be enameled (thin coat of varnish rather than bare wire
or wire with plastic insulation). This is often sold as 'magnet wire'.
Good luck!

Unfortunately the coil was so chewed up I couldn't reliably count the number of turns.

However, I did piece all the lengths together and I would assume that with the same total length of wire, wound in the same manner (or as close as possible) would result in the same number of turns.

I have numerous low voltage transformers that I'm never going to use for anything else- I'd thought to salvage the wire from one of those, provided it's not potted. I also have a huge copper coil (magnet wire) from a TV yoke, but I think that's too thick to use. Fortunately, the secondary coil was untouched, and so I have it for both a reference in wire size and winding pattern.

Looks like you did your best to gather all the available info. It's time to start
experimenting! As long as you get the correct phasing (relative polarity of
the two coils), it should oscillate. Personal message to follow within one day,
bye for now.

Yep... We'll see how it goes.

I'm waiting for a nice sunny (and insect-free) day so I can finish derusting the chassis and power transformer casing, and I hope to get in an order for some replacement capacitors once I've tested for out-of-spec resistors.

Thanks for all your help!

Just finished re-winding the coil (pic below) and I'm waiting for the wax to harden. The CRT yoke had perfectly salvageable wire (and more than enough on just one winding- I nearly filled an 800 yard thread spool!

I reinstalled the coil and looked at the circuit diagram- it seems that there are some differences- (or someone has already "serviced" the radio.

Particularly, C25 and C26 are 0.01 µF (vs .03) and one of the filter caps in the can is 100 µF as opposed to 40 on the schematic.

R5 and R31 are completely absent.

Regarding replacements, I take it aluminum caps are fine for the electrolytics, and ceramics to replace the plastic and paper ones?

Also, can someone confirm whether C12,22,16, and 17 are electrolytic? They have the same schematic symbol as the filter caps, but like kinda like the plastic jobbies. (or just leave them alone?)

>Particularly, C25 and C26 are 0.01 µF (vs .03) and one of the filter caps in
>the can is 100 µF as opposed to 40 on the schematic.

Those 2 capacitors bypass the power line to the chassis to filter out some
interference. They are sometimes called 'death caps', because while
they are useful for their stated purpose, they also increase the leakage
between the power line and chassis, and bring up some shock hazard.
The lower value is possibly a production change, you need not worry,
but make sure good capacitors are in those spots. The 100 µF can
is probably fine for C23, but at C24 it may overstress the rectifier tube.
Better limit this one to 40 or 50 µF.

>R5 and R31 are completely absent.

Maybe they were removed by someone who wanted to disable the
radio section; these resistors provide the proper voltage and current
to tubes 6BE6 and 6DC8. The node between R3 and C5 should
definitely not be connected directly to the function switch, or the
tubes may be overloaded. You could replace R5 and R31 by a single
10 kohm, 3 to 5 W resistor. (note added afterwards: maybe the
resistors were moved to the part of the supply line on the other
side of the switch, somewhere to the right of C11)

>Regarding replacements, I take it aluminum caps are fine for the
>electrolytics, and ceramics to replace the plastic and paper ones?

Well electrolytics and aluminum electrolytics are essentially the same
(although there are also tantalum electrolytics, not very often used
in tube gear). Ceramic capacitors don't usually come in large values
(0.1 microF) and reasonably high voltage ratings. But in this radio,
probably anything with correct voltage and capacitance rating will do.

>Also, can someone confirm whether C12,22,16, and 17 are electrolytic?
>They have the same schematic symbol as the filter caps, but like kinda like
>the plastic jobbies. (or just leave them alone?)

Those cathode bypass capacitors are definitely electrolytic, but they
are low voltage units, that is why they are smaller. 6- to 15- volt
units would be fine for C12/C22, and 25-V units for C16/C17. You
can read the cathode voltages on the schematic, respectively 1.1 and
12 volts. These should be replaced, as any leakage will screw up
the bias on the tubes. P.S.: modern plastic units for C12/C22 would
be fine if not too physically big; some audiophiles will even tell you they
will improve the sound!

Good night.

The 100 µF can is indeed C23, so I'll see what I can get and may change it for a 40 if circumstances require.

I'll also look in to good replacements for the death caps; chassis ground is also turntable ground, so it is a big issue.

It turns out that R31 and R5 are present after all; they are before the function switch and tucked away, so I did not see them until I searched thoroughly.

I'm placing an order with Digi-key for other electronics supplies, so I'll get as many of the caps as I can there... if all goes well, I may be able to do a preliminary test next week! *crosses fingers*

Not much other radio progress, but after an afternoon with some steel wool and rust remover, I think I've eliminated all the rust. The line cord has also been replaced (the prongs on the old one were bent up and corroded.)

Hello again,

Regarding the death caps and shock hazards, it might be a good idea to
install a polarized plug (maybe cannibalized from a dead TV) with the
neutral (wide blade) connected to the lower side of the power
transformer and the live (narrow blade) connected to the upper
side (the one with the power switch). This would ensure that the
resistive link to the chassis (R55) would remain on the neutral side
of the line. R55 is part of the filter along with the death caps.

I found the polarized line cord I had; and installed it.

I'm currently re-painting the transformer case and have removed the filter cap can (and gutted it) for re-stuffing.

Capacitors have been ordered and are on the way!

There's a bit of a lull in activity now, since I'm waiting for my caps to arrive. More photos have been posted and updates made to the restore log on my site.

http://vintagepc.co.nr/site/index.php/stuff/radio/

Hope it tides everyone over!

Still twiddling my thumbs. I'd hoped the caps would arrive today, but probably will on Monday (because of the holiday Thursday).

Can't do much else until I have those, but I did rig up an external RCA input using a dual-pole dual-throw switch and some RCA jacks, plugs, and shielded audio cable... so when the set is done, I'll be able to switch between the internal turntable and an external source at the push of a button!

The only issue I could see is with the set's floating ground- Would it cause an issue if I plugged in an audio source with a hard-wired ground?

Anyway, once I've recapped, what would be the best way to power up the set? I don't have a variac (alas) but I'd thought to pull all the tubes, check the transformer output voltages, and then put the tubes back in one by one, testing voltages (indicated on the schematic) as I go.

Still twiddling my thumbs.

...
The only issue I could see is with the set's floating ground- Would it cause an issue if I plugged in an audio source with a hard-wired ground?

Anyway, once I've recapped, what would be the best way to power up the set? I don't have a variac (alas) but I'd thought to pull all the tubes, check the transformer output voltages, and then put the tubes back in one by one, testing voltages (indicated on the schematic) as I go.


No problem with ground floating ground, it will just cease to be floating
when connected to a grounded source. This is not really a hot chassis,
the power transformer does provide isolation. You can ground the chassis
to earth if you make sure you have the correct power line polarity as
discussed before, end even with incorrect polarity, the leakage will
be small and tolerable as long as the line filter components (one
resistor and two capacitors) are OK.

Do not plug the tubes one by one! Instead, install all the tubes
except the rectifier. It would be best to start up with a variac
(do a bit of research with this word), or with an incandescent
bulb in series, but in a pinch the line fuse will do. With power
applied, tube heaters should light up (not very bright, but visible
in the dark). Let the set run (while watching) for maybe 30 minutes.
The power transformer should get mildly warm, but not any hotter.
Without rectifier, no DC will be generated, so no voltage measurements
to be done at this point.

You may use your old tubes for this test (hope you did not discard
them), many or all are likely to be good. Bad tubes would be
detected later by measurements and substitutions.

Now with power off, install the rectifier tube. The time for the
full test is approaching. Securely hook up your DC voltmeter to C23 and
ground. Turn on power, and watch the meter. The situation
is now the same as before, so no sparks are expected, but as
the rectifier warms up, the correct DC voltage (275) should appear.
If the value is substantially lower, it means you have a short somewhere
down the road from the rectifier, HIT THE POWER SWITCH. Otherwise,
listen for some hum in the speaker, etc. You may start doing the
voltage measurements you suggested.

This should get you going for a while. Good night.

Yes, I did keep the tubes that were in there :) I'm not tossing anything until I know for sure it's bad.

Regarding the variac... I might be able to borrow one from work... I'll have to ask. If not, then I should have enough stuff to make a dim-bulb tester.

Good news- I've sourced a variac that I can borrow.

With this, I've read that the procedure is to bring the set up in steps (typically 10v steps/30 min?) Can someone confirm or provide a link to a good guide for doing this? I've found a few, but those all discuss re-forming the original filter caps and precautions if you're bringing the set up with the original paper caps- I'll have replaced all of those by then, so I don't know if the process differs much.

There's also something about a point around 40-50V where things get near the minimum operating voltage to run, and that it should be left there for longer.

Thanks!

Re-forming applies to the power supply electrolytics. If they are new and
correctly wired, there should be no problem with those capacitors.

Without the rectifier, you can turn up the variac as slowly as you wish, but
when you do the test with the rectifier in place, dont run the unit under
say 80% of nominal voltage for more than a few minutes. If it seems
to be idling OK at 80%, you can get it up to 100%. This radio is much simpler
than a TV, where for instance lack of horizontal drive could fry the sweep tube.

Also, in addition to what I wrote to you last time, you should do the initial testing
with rectifier with the function switch in PHONO or STEREO, rather than
RADIO (or BC). This will keep the two radio tubes off the high voltage.
Of course, this test should be done with the speakers (or load resistors) connected.
After checking the high voltage at C23, the next measurements should be
the cathode voltage at the output tubes (pin 2 of each 6AQ5, 12 volts) and
at each of the driver tubes (pin 7 of each 6AU6, 1.1 volts). Correct values
at these four points will almost certainly guarantee that the tubes are correctly
biased.

Once you get the audio section working, we'll have a look at the radio part.
Good luck.

Thanks for the info- good thing I asked too- since sometimes being to cautious is just as dangerous as not.

My capacitors arrived today... So I'm going to have me a restuffing party!

Just spent an afternoon recapping... what an experience.

Nothing quite like trying to figure out how the leads are attached when they all run in to a giant glob of solder.

Anyway, pictures and more info posted in the build log.

I'm waiting to get that variac before I test it... that should be next Monday. :thmbsp:

I've also thought about refinishing the cabinet. There are some nice pieces of solid maple, but the rest seems to be made of hardboard. It's all coated with some horrid brown paint-on coating that is peeling like crazy.

I'd thought to strip it and put on maple veneer (and varnish it) instead. Can anyone with cabinet work experience advise on the best way to do this?

Okay... some good news, some bad. The good news is I've borrowed a variac. The bad news is that I borrowed it as-is, and unfortunately, it seems not to do anything.

Looks like I'll have to fix it before I can fire up the radio. I've already done the background research and have figured out that it's either going to be a simple fix, or not at all. Fingers crossed! :)

Some even better news... The variac just had a funky switch, and is working now!

I've done the preliminary non-rectifier tests, and all seems well so far- transformer didn't even get warm, all of the tubes lit up, and both the dial lights lit.

I kept the voltmeter across the filament line, and it's bang on at 6.3v AC.

(the occasional twitch to 6.4, but I expect that's because the wall voltage is 120V as opposed to 117 the set wants.)

I also checked the chassis to ground voltage, there's about 33v AC, so no major shock hazard.

I also probed the HV out from the transformer, that's at about 500V AC.
It seems a little on the high side, but I still live in a silicon world where rectifiers are that efficient :)

It's getting dark now, so I'll wait until tomorrow to put in the rectifier and do the secondary tests. Pictures of that warm tube glow coming soon!

Edit: Pics posted in the build log. Here's one to get you started...

The HV from the xfrmr. will drop when the rectifier is in and the tubes start drawing current.

That's true; I've seen it to some extent with low-voltage unregulated AC wall warts, but I didn't realize it was that extreme at higher voltages... but it makes sense if you think about it.

Cheers!

We have liftoff... REPEAT, WE HAVE LIFTOFF!

I get audio from the speakers using a test CD (has tracks for checking left-right separation, phasing, etc.) and player hooked up to the Phono input. Pots could do with a little cleaning, but that's not an issue unless you're moving them.

High voltage is okay (~280 V across C23 with variac at 95%).

However, I didn't run the set for very long- I checked the other test points and get 17V on the 6AQ5s, and about 0.8V DC on the 6AU6s.

That's well out of the 20% voltage tolerance, but I checked the two 470 ohm resistors on the AQ5s. one was a bit high- 500-something ohms-, and the other within 10%; so that's not the cause (both have 17V on them).

Thoughts?

Hello again, and congratulations for keeping the smoke where it belongs (that is
inside the components)!

The bias on the output tubes is determined by R33, R34 and R18 (as well as
the two cathode resistors of course). Once you have checked those five resistors
and made sure they are within tolerance (+/- 10 % I assume), the tubes should
work properly. You may also want to check the plate voltage at pin 5. Your
present results (cathode voltage higher than expected) mean that the cathode
current is a bit high. Also make sure your cathode bypass capacitors are correctly
wired (+ to cathode, - to ground). Good luck!

Yep... at least one of the 33K ones is on the high side. What wattage should the replacements be? I only have some smaller jobbies on hand (2mm dia. x 6mm long)... but I'm not done searching yet.

Edit: found some 1/2, possibly 1 watt ones...

1/2 W should be fine, screen voltage is close to plate voltage.

I've replaced the out of spec 33Ks, and one out of spec 470.

The 2.7 reads 2.6, so should be all right... but there's still 16V on the pins.

I did check pin 5 as you suggested, and it is 265v bang on.

Check the voltage on the first grid (pin 7). This should be ZERO. Any positive
reading here indicates some leakage from the plate of the previous stage (through
a defective capacitor C14 or C19). Another thing to check is to make sure that
the speakers are connected to the correct taps as found when you got the set.

The present conditions are giving you about 8.5 W plate dissipation, while the
tubes are rated for 12, so I would say that if sound through the speakers is
acceptable, you could leave things as they stand, and just go around the
four audio tubes and measure all the specified voltages. This will give us a
global picture of the operating conditions of the audio stages. You might
also try substituting the brand new tubes (6AQ5s first, then 6AU6s) and see
what this does to the voltages. Worn tubes can do funny things...

There's about 100mv on one pin 7, and 50 on the other.

The speakers are connected correctly- I made a diagram before I disconnected anything. (and I verified that they are indeed 8-ohm speakers)

Both C14 and C19 were originally replaced, and I doubt _both_ of them would be bad... but it's possible.

The only other voltages on the schematics is the 1.1 on the 6AU6s;
here I measure about 0.8 on one tube and 0.5 on the other. All of the HV seems to check out, so I'll try doing the tube roll. (any relation to the grid plate shuffle?... Sorry, couldn't resist.)

Also, PM to follow.

No difference with the tube changes... so I think that if we're within operating specs, I have myself a working set... I should note that there's some speaker hum when I measure the voltages on pin 7... I assume that's normal, since the meter is tying the pin to chassis ground.

Edit: I did find that changing the function switch to BC (as said on the schematic) lowers the voltage to about 14V... within the 20% tolerance.

However, I checked some of the other voltages. Pin 6 of the 6AQ5 should have 230V, but there is 265. Also, the 42V and 56V on the 6AU6s actually measure at about 10 and 20V. Wierd.

I doubt it's the cause, but I did note on the schematic that R35 (filter section of power in) masures only 228K as opposed to 270K.

Bingo!

Will look at your PM later, just found out something important (from what I just
read)! When in phono mode, the power supply does not feed the two radio tubes,
so current through R18 is lower, and so the screen voltage on the output tubes
does get higher, increasing cathode current. Also touching the control grid
does induce hum as your whole body, meter, etc. act as a coupling capacitor
to feed hum to the amplifier stage. Doing this to the grid of the previous
stage (6AU6) should induce even louder hum as you now have two tubes
amplifying.

The funny voltages on the 6AU6 tubes: do they remain funny when you set
the switch to radio? If the two channels have different readings, something
is wrong with components... Bye for now.

You mentioned that the voltage on pin 6 of the 6AQ5 tubes was 265 instead
of 230. Something might be open in the network formed by R21, R24 and
R13, which would explain the wrong voltages measured on the 6AU6 tubes.
Those parts are nearly 50 years old (just like me), don't forget, but
fortunately there are not too many of them. Good luck.

Recieved and understood :) I'll re-check the voltages with the switch in radio mode.

Well, I've ended up replacing just about every resistor in the set (save 5 or 6). The tube voltages around the 6AQ5 seem to be better now (at 12V in radio mode), but there's still some weird stuff going on around the 6AU6... I get about 30V on pin 5, and 20V on pin 6. This does change when I adkust the volume knob. However, the 1.1V line is now at about 0.9V, much better than originally.

Also, the tubes in the radio part are way out;
There's 89V on the 6BE6. (I think the schematic says 85) and there's well over 40 on the 6DC8. Could be okay if the schematic shows 56, but it looks more like a 36 to me. Haven't tried to tune anything.

There are also a multitude of disc caps and resistors attached to the volume knob, of which I can't find any trace on the schematic. I haven't checked those yet. A wild guess says they may be to filter interference, but I don't know. Pics available on request.

The set's probably been too damp, as these are carbon composite resistors.

I should also note that the replacements are all salvaged resistors, and while I've checked them to make sure they're within 10%, I have no idea how they behave under load.

I'm inclined to go and buy new ones and just replace all of them for this reason, and also because the leads on these are much shorter than what was in the set; so I've had to do some clipping and solder to the old leads... which doesn't look pretty, but it works in a pinch.

Reese- hope you have some advice (even if it's just to go buy new resistors) since Electroking is away for a few days :)

Last message before I get on my trip!

The voltages on 6BE6 and 6DC8 look fine to me: 89 is only 5% over 85, and
40 is only 11% over 36 (correct as I see it), so no big problems here. Salvaged
resistors are OK if they measure OK. I would suggest at this point that you
let it cook for a few hours, and come back and do some measurements. Just
have it play some background music from a CD player or similar source so you
know no catastrophe is happening. Back in a few days!

All right then... have a good one!

Ah, I see how you calculated the voltage %s... I was thinking 36+(20%x36)=43.2V max, as opposed to (40-36)/36=11%

I'll check the price for new resistors just for kicks; if it's not much I'll just replace them all; I know the sloppiness of the current job is going to nag at me, and some of the replacements get a tad warm for my liking...

Edit: 100th Post! YaY!

Also... resistor prices: I can get all of them for $7 (excl shipping.)... so I'll probably just toss them in in the next order (digi-key) This is for carbon film 1/2 watts, with the exception of the 2watt ones needed in some spots- these are metal oxide film.

Also, is there anything I need to worry about before running this set off wall voltage? right now, I have it on the variac at ~95%, but the set was designed for 117V...I've read talk of dropping resistors, but this is only when replacing a metal rectifier.

Ok... been running the set for a while with a CD player. Sound is good (even on the built-in speakers), but there are a few things:

1. Left channel is fainter than the right. Likely a dirty balance or volume pot.

2. There's a faint hum with no audio and the volume on max. This goes away at lower volumes, so it's not of major concern.

3. Power transformer gets hot- still touchable, but not comfortable, kind of like a fresh cup of coffee. Voltages are steady and looking good after ~2h of running.

4. Some sharp audio (e.g. guitar) had a bit of distortion to it- It went away when I fiddled with the tone pot, so I think it is again, a dirty pot.

What is the suggested approach? replace the pots or clean them?

I don't have any deOxit on hand, are there good substitutes? It already got much better just from working the controls for a bit with the set off.

Edit: Just re-probed the radio tube voltages. They start high and eventually come down and stabilize. The 6BE6 is indeed at about 88V, but the 6DC8 is at about 55... well outside a 20% tolerance, if the schematic indeed shows 35V. It's too fuzzy to make out; can someone see whether it is "36" or "56" V? on the 6DC8? This datasheet suggests the tube can handle it (http://tubedata.itchurch.org/sheets/020/e/EBF89.pdf) but it may indicate part of the reason the AM isn't tuning.

Also did a quick check on sweeping the dial, but no stations came in. Could be that there's nothing rolling in yet, but I should at least be able to find the local AM at 1450... but it's possible that rewinding the oscillator bumped it off the top edge of the range.

You'll get varying responses, but a few drops of WD-40 dripped in where the terminals come out of the pots, and working the pots back and forth many times, has worked for me lots of times.

Thanks, tried that and it has reduced the noise considerably.

I think I may also have located part of the balance problem... There's some weird stuff going on with the volume control that's not in the schematic. It may also be the result of differing resistors in each channel- while they are all within tolerance, one example is the 100K ones; one channel has a 100.6K, the other is about 107K... Should they be as closely matched as possible?

The pot has a 4th lug which appears to be some sort of center tap- resistance goes from 300K to 0 and back up again as the knob is turned.

The schematic just shows the wiper going straight to the 6AU6, but here, the wiper goes through a 220K to ground, as well as to the 6AU6. One channel is shielded, the other isn't, so that may well be the source of some hum.

In addition, the audio input from the function switch runs through a cap to the 4th lead of the pot, then to a 47K resistor, through another cap, and to ground. The same circuit exists on both channels.

Does anyone have an idea what purpose this might serve? The mounting for the volume pot is different than the others, so I wonder if someone changed it and added a hack to make it fit/convert a linear to a log pot? My meter doesn't go to 3 megs, but afaict, it is a 3 meg pot.

Does someone have an idea what this might be?

Greetings from FixitLand!

The pot has a 4th lug which appears to be some sort of center tap- resistance goes from 300K to 0 and back up again as the knob is turned.

The schematic just shows the wiper going straight to the 6AU6, but here, the wiper goes through a 220K to ground, as well as to the 6AU6. One channel is shielded, the other isn't, so that may well be the source of some hum.

In addition, the audio input from the function switch runs through a cap to the 4th lead of the pot, then to a 47K resistor, through another cap, and to ground. The same circuit exists on both channels.

Does anyone have an idea what purpose this might serve? The mounting for the volume pot is different than the others, so I wonder if someone changed it and added a hack to make it fit/convert a linear to a log pot? My meter doesn't go to 3 megs, but afaict, it is a 3 meg pot.

Does someone have an idea what this might be?

The fourth lug on the pot usually means it has a loudness tap. Components connect to it in such a manner that bass is accentuated at lower volume levels, making the sound (supposedly) more "full-bodied." Anyway, as you note, the schematic doesn't show this. No harm in leaving it as is, at least for the time being. It could've been a factory circuit change.

Having one channel shielded (I assume from the function switch to the 6AU6 grid) and the other not shielded is definitely a hum issue. Does the hum you hear come from the unshielded channel? Or both, equally? If the latter, we're talking a power-supply issue most likely.

From the volume-control wiper to the 6AU6 grid, you say you have a 220K resistor to ground as well. That's a good idea, actually; should the wiper go open-circuit, without that 220K resistor the grid would float and cause the tube to operate erratically at best (go into runaway at worst).

Take care,
--
J. E. Knox 'The Victor Freak'

Having one channel shielded (I assume from the function switch to the 6AU6 grid) and the other not shielded is definitely a hum issue. Does the hum you hear come from the unshielded channel? Or both, equally? If the latter, we're talking a power-supply issue most likely.

From the volume-control wiper to the 6AU6 grid, you say you have a 220K resistor to ground as well. That's a good idea, actually; should the wiper go open-circuit, without that 220K resistor the grid would float and cause the tube to operate erratically at best (go into runaway at worst).


Haven't checked for sure, but I do get the distinct impression that the hum is coming from one speaker, not both.

I've got plenty of shielded wire floating around in my parts box, so I'll replace it anyway. The hum is only noticable with the volume at or near max, so the power supply is doing a very nice job.

Regarding the volume control, the 220K does indeed serve to make the pot a log-pot instead of linear. Doing it this way is far cheaper, since log pots are more expensive. I'll have to replace them, since the readings at the same setting are different for each channel... and probably contributes to the balance issue. (and it's practically impossible to get an accurate reading of resistance with things in parallel and the uncertainty of a variable control!)

Edit: Yup, the 220s were out of spec. Replaced them and now the balance is equal on both sides.

You mentioned the loudness tap; this explains why at about 1/2 the control, the bass suddenly jumps up in volume... Suggestions to fix? The 47K resistors seem to be within spec.

I've had another thought cross my mind (stop groaning! :D )

The set gets nice and toasty just sitting on top of the cabinet; I don't know if I like the idea of enclosing it. I have plenty of PC fans in the parts bin; I thought to mount one just to get some air circulation over the tubes/power transformer.

I figure the best approach would be to tap the switched "phono motor" outlet with a small 12V wall wart to power the fan, and rig the fan to blow across the tubes and out the back (or vice versa- in the back and over the tubes).

Good idea?

Those sets were made to run without fans, as long as the back is ventilated, but there's nothing wrong adding one: heat is the enemy of all electronics.

you can also get similar small muffin fans that run straight off the AC line...with an ac rated one,you wouldn't need an adapter,you could just add a plug and connect it to the phono outlet...tho often these type of small fans tend to make more noise than they need too running full speed and can use some kind of speed control to slow them down and cut out some of the noise

Thanks for the advice.

This is a nice quiet one that came from a dead PC power supply.
I've got it on a variable wall wart (Set to about 10V) to keep the noise down.

I've also got a pass-thru power plug I can drop in between the brick and phono outlet, so all's good to go! (I'd otherwise use the TV chassis outlet, but this one is switched so the fan is only on when the marshmallow toasters are running...)

Basically, now all that's left to do is figure out the radio and why it's not working...

electroking will help you with the radio! But it will have to wait one more day,
I have a rush job to finish tonight. Bye for now.

Hooray! :banana: *party* :banana:

Seriously, welcome back, and take your time. It's been quiet without you... even though I've been enjoying CDs on my tube set (and contemplating roasting some marshmallows on it...). Really makes you realize how much some speakers/sets sound like you have your head in a tin can.

I'm pretty tempted to put a decal on the front of this set that says "electroking"... Much nicer model name than "stereo Hi-Fi", don't you think?

Edit:
Also, did a quick test at wall voltage; the HV goes up to 303V... 6% over 285, so that should be all right - this is with the radio tubes off the HV.

I've whipped up a spark-gap transmitter with an old relay and .1 uF cap, so we have something to test the oscillation with even if there isn't any AM rolling in- as is usual during the day (with the exception of a faint local one).

Edit: Some more news... both good and bad. The good news is the set oscillates; I can hear the buzz from the spark-xmitter when I bring it close to the antenna. The bad news is no stations... Anything that needs to be checked, or is it adjustment/alignment time?

Hello again,

Well, a spark gap gizmo will indeed produce noise that can be received across the
band, but it is a crude instrument at best...

I won't start writing an essay about the theory of superheterodyne receivers right
away (but I can do it if you tell me it would help). Instead, let's determine if
the oscillator is running. When tuned to the bottom of the band (550 kHz or so),
the oscillator should be running at 995 kHz, and at the other end of the band
(1600 kHz), it should run at 2055 kHz. These figures are just 455 kHz about the
desired carrier frequency.

If you have two working AM radios in the house, you should be able to do some
testing. Just one working radio is actually needed for the test, but two will help
demonstrate the procedure. If you set one of the radios at the bottom of the
AM band, its LO will run at about 995 kHz as stated above, and if you set the second
radio around the latter frequency, you should be able to find a spot where you're
just picking up the radiation from the first radio. You have to try it to hear the
effect. Now as you increase the tuning of the 'source' radio, you can track its
radiation by also increasing the tuning of the 'observing' radio.

The trick to check your receiver is to use the same 'observing' radio as above
(it will work fine if it is a small portable unit with a speaker), placing it near the
oscillator tube (6BE6) in your Fleetwood. You should be able to crudely
determine whether the oscillator is running.

Let me know what happens next. Good evening.

P.S.: the method described, using a small AM radio as a probe, will not work for LO
frequencies above the upper limit of the probe (1600 or 1700 kHz), corresponding
to carrier frequencies of about 1150 to 1250 kHz. There is no guarantee that an
oscillator that works at a lower frequency does not quit at some point in the
frequency range.

Thanks for the details; I had assumed the SG was very crude, but better than nothing; of course now I know better.

No need for the essay (unless you want to- I'd still read it out of interest); I've had a look at the wiki article, which does an interesting job of explaining how it works.

I've got a couple of AM sets around here; I'll try the test and we'll see what happens. It'll have to be tomorrow though; it's getting late and I have part-time work tomorrow morning. ( earning some spare dosh to fund such projects as this, of course... *grin*)

Okay, the results are in...

I practiced for a bit on my bookshelf stereo using an old walkman. It picks it up quite well, and I was able to locate the noise (Kind of like a pulsing hum, for lack of better description) and track it up and down the dial.
(Also found that the bookshelf system makes a LOT of noise.. I could even locate the frequency of the VFT display; it would pulse whenever a new segment lit up or went out.)

However, on the tube set, no luck. (took the shield off the 6BE6 for this test). I tried sweeping the frequencies on both the tube set and the walkman. I picked up some noise, but nothing that changed on adjusting the set dial.

Hello,

Removing the shield on the pentagrid converter was definitely a good idea to
enhance oscillator radiation. You now have to see why it's not oscillating.

Check the continuity of the IF transformer primary (1st IF transformer) that
feeds the plate of the 6BE6. Then, under power, measure the plate and
gride voltages on the tube and compare with schematic. Testing with the new
tube might also be a good idea. There is also the possibiliy that the coil was
not installed correctly after you rewound it. Oscillation depends on feedback
from grid (pin 1) to cathode through the circuit formed by C4, coil and C2+C2A.

Also, as I told you before, the oscillator is more likely to work at a lower frequency
if something is marginal in the circuit, so just leave the tuning at the low end
of the band while searching for oscillations with the test receiver. You may also
want to disconnect the coil from the variable capacitor and make sure the
capacitor itself is not shorted (bent plate). You have to disconnect the coil
to do this, otherwise you would be just checking the continuity of the coil.

The article on 'pentagrid converter' in wikipedia might make good reading if
you haven't already looked up. Bye for now.

Hey,

I re-soldered the coil's ground connection since I wasn't happy with it; but it didn't seem to make a difference.
I re-checked the installation with my original photos and drawing, and I think I got it right.

Voltages are also within tolerance (~90V, <10% over 85) and the primary IF is not open-circuit.

Tried the other tube, and I got some static out of the speakers, but couldn't locate the frequency either. I should also note that with this tube, the IF voltage dropped down to about 69v... Odd?

C2/C2A are not shorted.

Are you sure that you rewound the coil in the same direction as the old one was and that the coil ends were connected to the terminals same as originally? Oscillation depends on the two coils being in the correct phase WRT each other. A test (and possible correction) would be to reverse the connections to ONE of the coils and see if it oscillates. It may be way off but should tune in something on the dial or make a squawk somewhere in the broadcast band on another radio.

Also, the new tube caused a drop in plate voltage, indicating that it was drawing
more current than the old one. I would stick with the new tube, assuming that
the old one was tired. The exact plate voltages on the schematic may be
based on reception of a station, which would cause a certain level of AVC (negative
voltage across R7, providing a gain reduction of the two tubes by biasing their
control grids). Good luck, correct operation may not be far off!

...would be to reverse the connections to ONE of the coils and see if it oscillates.

:banana:D'oh! WE HAVE A WINNER!:banana:

Swapped the coil leads, and almost immediately found the sweet spot using the handheld. Followed it up and down the dial for a bit, then tried to find a station (plenty of squeaks and noise at this time...).

Found one, but it required cranking the volume about 1/2way and shoving the 'ANT' spade connector in to a 10 foot USB cable (which is currently masquerading as a radio antenna).

This was with the old tube, mind you; I did another check on the voltages while it's on a station, and it's now sitting at 106V... so as you suggest, the tube could indeed be weak. Will pop the other one in after it cools down to see if there's a noticeable difference. (Edit: Doesn't sound like a major difference to me... and the voltage on the new tube also reads 100 now)

I would have been willing to bet that I'd rewound the coil properly; I remember putting it on the end of a pen and pulling the broken wire off so that it unwound in an overhand fashion... and the current one is wired in the same way. (it will only go on the pen one way b/c of the lugs on one end.). Next step is to figure out if we match up with the dial; that'll have to wait until sundown when more AM starts coming in (and until I pop the chassis back in the case).

A night of BC band DX is in sight! Just have some fun, a poorly aligned radio is
much better than no radio at all...

Try for Radio-Canada in French from Toronto (860 kHz). Easy to identify
from the language, and should be a fairly solid signal. Bye for now.

Indeed. I played around with the set at about 10PM; there's a lot of AM DX coming in, especially in the higher frequencies.

I've run in to a spanish station, a station from NY, and ironically enough, one of the first I hit was an "oldies" station playing some '60s music... Felt like a time warp for a moment.

Wasn't able to find 860, but I'll try again tomorrow; I have 2x 50' pieces of unused CAT5 that will make for a nice antenna :)

I've set the dial indicator to run from the edge to edge of the dial, and some adjusting will probably be necessary; I found 1010 at ~90, but not entirely sure since some stations fade in and out.

The trick to get the stations in the right spots is to adjust the oscillator trimmer
(C2A) and the coil slug. This is described in the last two items of the alignment
instructions (numbers 5 and 6). They suggest using a signal generator tuned
at either end of the band, adjusting the coil at the bottom and the capacitor
at the top. As mentioned (item 7), these two steps will somewhat
interact and it is best to repeat them two or three times, until both ends
of the band are tuned with correct dial readings. You can identify two stations
that are near the edges of the band, and use them to do the adjustments.
You can finally perform item 8 (adjusting the trimmer on the other part of
the variable capacitor, C1) using a station that is near 1400 kHz. The last adjustment
does not affect the oscillator, and thus does not move the spot on the dial
where the station is received, but it peaks the resonance of the input circuit
to maximize the received signal strength.

I see you are getting about 110 kHz error near the middle of the dial, so you probably
did not goof in estimating the number of turns of the coil. Adjustment should
be possible.

Ideally, you would also have to do the IF alignment as described in items 1-3, but
that can be done without if you don't have the instruments. Good night.

P.S. You need plastic tools to adjust both the coil and the trimmer capacitor.
Usually, the coil slug needs a hex-shaped tool (Allen Key), you may be able to
carve a useable one from a soft plastic rod. The capacitor just needs a flat
screwdriver, again easily improvised.

Should be able to find WBZ Boston at 1030, they're a powerhouse. Other strong NY stations are WABC 770, WCBS 880. Of course, I don't know if their transmitting patterns shoot up your way. They are all pretty much news all the time and so identify quite frequently.

A stupid question perhaps, but where do I find the oscillator tuning slug? Is that in IF can #1? (if so, top or bottom?)

The alignment page refer to the "broadcast oscillator (L2) tuning slug, but there's nothing on L2 for adjustment.

I did run across WBZ, I think- FOX news?

Edit: Also, two questions:
1. Do the resistors have a major effect on tuning/alignment? I want to order replacements for all of them so I can do a decent job of the point to point wiring instead of the hack-job it currently is with clipped and soldered leads.
2. The set can run at wall voltage, versus the 117 it was designed for... However, will this unduly stress the tubes? If so, what sort of dropping resistor would I need? (so I can add it to this parts order)

Wall voltage should be fine. Tube heaters do increase in resistance when the
voltage goes up, so the added dissipation is less than could be deduced from
a simple calculation.

The coil tuning slug should be inside the cardboard form. Did you reuse the
original form or did you make one yourself? It may be lost due to the damage
you observed on the coil. Maybe you could find something compatible in your
junk box. You might also find a useable slug inside a discarded IF transformer.
The slugs in your IF transformers should not be disturbed.

I don't thinkg replacing good resistors is a great idea if the soldering is half-decent,
even though it may not look that good. Some of the parts in there (coil, IF
transformers, etc.) are too easy to break.

Pending the fix on the coil, you may start adjusting the oscillator trimmer capacitor
just a bit at a time, and seing how you have to readjust the tuning knob to get
back on the station. That will tell you which way to turn to move the oscillator
in the desired direction. Good luck!

Ok, I'll leave the resistors alone (but for $6, I'm still ordering a spare set just in case...)

There was nothing in the original cardboard form (which I re-used). You can see it in 1040.jpg ( http://vintagepc.co.nr/radio/IMG_1040.JPG - not posted in the build log b/c of fuzziness). That picture was taken as soon as the chassis came out of the set and the mouse fluff removed.

You can also see the inside of the coil is shiny; I would assume the slug was threaded for positioning; it looks like there may never have been one... (also note the schematic doesn't show the "adjustable" symbol on L2 like it does for the IF cans)

I should have something in the parts box; I know for sure that I have the core from an old antenna (that can be cut to size), but that's too long. Roughly what size am I looking for?

If there is no slug, then the oscillator would be adjusted with the trimmer capacitor screw on the small section of the tuning capacitor. Find a station at the high end of the dial that you know the frequency of. If you tighten the screw 1/8 of a turn, this will move the station up the dial. Turn the dial higher and find it. If you turn the screw out 1/8 of a turn, the station will move down the dial. Continue "walking" the station either up or down the dial, whichever applies in your case, 1/8 turn at a time, until the dial pointer is at the correct frequency.

Each little trimmer cap is in parallel electrically with its tuning capacitor plate section. Together they act as one capacitor. When you tighten a trimmer, its capacity goes up so to keep the same frequency the large cap plates have to open up more, and vice versa.

After you get the stations at the high end of the dial where you want them WRT to the dial markings using the trimmer, then on a weak station around 1400 or so (can be WAY down in the mud weak) peak it for max volume using the trimmer on the other, larger section of the tuning cap, which is the antenna section.

Holy mackerel, it just dawned on me that you rewound an oscillator coil, and made a pretty one per the picture at that. Ain't a whole lot of newbies to tube radios that have done (or would even try) that! That's the fun of this stuff to me: making something out of nothing!

Emmm.... you sure that's right? In my case, the smaller one is the one ID'ed as C1A, which is in the antenna circuit.

The larger one (more plates) is C2A, which is in parallel with the oscillator.

The alignment instructions also contradict you; they say to adjust C2A first (bigger) and C1A last (smaller) (then again, they also say to adjust L2, for which there is no evidence of adjustments ever having been possible).

Holy mackerel, it just dawned on me that you rewound an oscillator coil, and made a pretty one per the picture at that. Ain't a whole lot of newbies to tube radios that have done (or would even try) that! That's the fun of this stuff to me: making something out of nothing!

Awesome feeling, isn't it? Excuse me while I laugh maniacally while I power up the set, the lights dim, and lightning flashes in the background.... "IT'S ALLLLIIIIIIIIIVEEEEEEEEEEE!" :D

The instructions we have (see the second figure in post number 20) do call for
adjusting the oscillator at two points with both the trimmer cap and the coil.
The manufacturer may have dropped the adjustable coil in production, in which
case the oscillator would be aligned only at the high end of the band, and
some error would have to be tolerated at the low end.

Typically, you will find a hole in the chassis above the coil so the tuning tool
can be inserted from the top. Do you see the hole?

Note regarding the alignment instructions: I don't see any contradictions.
Items 1 to 3 refer to the IF alignment (which can be left out). Items 4, 5 and 6
are the steps for aligning the oscillator to get the stations on the right
spots, with 7 telling you to repeat 5 and 6. Finally item 8 is the peaking of
the input circuit resonator, using the trimmer on the RF section of the variable
capacitor, that is the section that is NOT part of the oscillator circuit. Regards.

P.P.S.: the variable capacitor section for the oscillator may be bigger or smaller
than the RF section, depending on the coil used. Tracing the leads to the proper
circuit (and also checking the labels C1/C2 on the alignment drawing) is the
best way to determine which section is which.

I've never seen a two-gang tuning cap where the oscillator section was larger than the antenna section. Doesn't mean it couldn't be. On some very older sets they were the same size.

You can easily find out: tune in a station at the high end and tweak the screw on the smaller gang of plates. The station should move either up or down the dial.

The schematic may not exactly match your set. Does this set have FM? Those would be the really small gangs with just a few plates. For AM I'm talking about the plates that look about like this: scroll down to the picture of the dual gang air variable, with trimmer screws on the side. I couldn't quickly find a picture of a typical cap with the oscillator section smaller than the antenna section, but they used to be the "standard" in most radios.

http://www.midnightscience.com/catalog5.html

Apart from # of plates, that's exactly what I have. Take a look at http://vintagepc.site50.net/site/images/photos/large/IMG_1025.JPG

You can see it there; it turns out you're right and there's an error on the tube layout diagram; the tuning caps are mislabeled there, which is what threw me off.

I now see this is not true; the yellow wire runs to the lug of the coil (thus smaller section) and the green wire is bridged by the antenna (2-wire flat cable you see)

Thus, BIG=antenna, SMALL=coil, and therefore REECE=correct.

There is indeed NO hole in the chassis above the coil; the only one is a fold-out pin to which the ground lug of the coil is soldered. (and it does not extend over the center of the coil).

Did you look for a tuning slug accessible from below? It may be hard to reach,
but alignment is a bench job rather than an 'in-cabinet' job. If you find no tuning slug,
you will have to do with a single adjustment point as discussed above.

You're right of course regarding the mislabeling on the instructions. The antenna
lead (flat cable) is connected to the rear section (C1 on the schematic but marked
C2 on the figure). Good luck!

Did you look for a tuning slug accessible from below? It may be hard to reach,
but alignment is a bench job rather than an 'in-cabinet' job. If you find no tuning slug,
you will have to do with a single adjustment point as discussed above.

Nada. I don't see any possible way to adjust the coil.

This may well be intentional because the alignment on the set has to be in-cabinet; the dial face is mounted to that as opposed to the actual chassis itself - if it's out on the bench, you can't see where you're supposed to be!

In addition, we've already found a few differences on the schematic and the actual set, such as the line (filter) caps/resistor values and loudness taps/caps on the volume control.

Taking a pot-shot, I'd say the 4068 model is based off the 2053 and is either a later run or intentional design change, resulting from component supply issues or so (but it was either short-lived or so similar they did not want the added cost of making new schematics/layout diagrams). I'd be interested to see whether the tuning caps are also mislabeled on a "true" 2053. (note they're also mislabeled on the sheet stapled to the inside of the cabinet).

I will re-draw the schematics with the additions and upload them to the build log when I make the next update. There's really not much new going on that's picture-worthy at this point, hence the long delay in updates.

Also noticed that there's some rust on the magnets at the back of the speakers... worth worrying about, or no? It just looks like a small surface coat, not like the whole magnet is disintegrating.

All right, so you just locate a station near the top, ascertain the frequency, and
then adjust the oscillator trimmer to bring it to the correct spot. A simple comment,
alignment can be done on the bench with a signal generator, just jamming the needle
at either end of the range, and using the two frequencies specified (530 and 1620),
or in fact just the higher one since the coil is non-adjustable.

I don't think you need to worry about a bit of surface rust. I think your electrical
restoration is nearly complete. Congratulations, I look forward to the update in
your site. And I believe I already got all the credit due to me, which is not that
much, after all you did all the manipulations! This thread possibly contains more
posts over its lifetime than all the rest of videokarma, and I believe this means
something...

All right... Hope to have the set fully adjusted by tonight...

A simple comment,
alignment can be done on the bench with a signal generator, just jamming the needle
at either end of the range, and using the two frequencies specified (530 and 1620),
or in fact just the higher one since the coil is non-adjustable.


Dangit... Now I'll have to build a signal generator... (just kidding.)

I think your electrical
restoration is nearly complete. Congratulations, I look forward to the update in
your site. And I believe I already got all the credit due to me, which is not that
much, after all you did all the manipulations!
True, but it wouldn't have been possible without everyone's help! Next step is cabinet restoration and detail work... I've mentioned it before that I want to put some decent veneer over the hardboard crap, and strip/varnish the maple frame.


This thread possibly contains more
posts over its lifetime than all the rest of videokarma, and I believe this means something...

...and it shall be preserved in eternal glory when I'm done. (Going to mirror it on my site)

WoHoo! was tuning the set and I noticed my 6AQ5s have a faint blue glow to them... looks exactly like the "flourescence" described here:
http://www.jacmusic.com/html/articles/blueglow/blueglow.htm

Only noticeable in near-blackness. Looks pretty cool, and sounds great... hope to get some pics if I can; the dial lights give off a lot of light, so I'll have to block them with some cardstock or so.

Still waiting for some fainter stations to come in so I can adjust the antenna trimmer :) I did, however, bump up the stations to where they belong.

Whoops... double post, but I just _had_ to upload this (click for full resolution, ~900KB)... Enjoy! (this is a 10 second exposure, BTW, will try for a better one when there's less ambient light.


http://vintagepc.site50.net/site/images/photos/small/IMG_1265.JPG
(http://vintagepc.co.nr/site/images/photos/large/IMG_1265.JPG)

Edit: and another, for good measure (15 second exposure, near full darkness):

http://vintagepc.site50.net/site/images/photos/small/IMG_1268.JPG
(http://vintagepc.co.nr/site/images/photos/large/IMG_1268.JPG)

Also, physical restoration question for you guys; how do you clean the grille cloths on these sets? I can't remove this one without completely dismantling the cabinet.

Grille cloth: see if you can find a dry cleaning spray can called K2R. It's dry cleaning solution with chalk in it. Shake it up, spray it on, let it dry thoroughly for half an hour. The solution dissolves the dirt and the chalk soaks up the dirty stuff. Then you brush or vacuum the chalk off. Remove speakers first. If you can't find that you could try a spray foam upholstery cleaner. Before I used anything I'd try it on a little spot to make sure it wouldn't hurt anything.

Thinking about winding coils I remembered this video a guy made using a coil winder. The winder is really neat but what's neater is the trouble he went to making the video, coordinating the music right down to the scissors snip etc. I wrote and told him so a long time ago.

http://www.youtube.com/watch?v=FIOocMoRsYQ

My goodness, that was incredible... and all hand built by the looks of it!

Perhaps I should dig up my Lego Mindstorms kit and build something similar :)

Edit: Seems we can't get K2R here in Canada... I tried some PowerOut upholstry foam on a small spot, and it seems to be all right.

All right... Just an update for those following/interested. I've emptied the cabinet, and I'm currently working on that. I've spent the afternoon with a heat gun and various scrapers getting the multiple layers of paint off. Most is done, just a side panel and the legs to go. (Edit: and the record player "box" as well)

Hope to varathane those tomorrow, we'll see how far I get.

Reece: I've seen you re-veneer some stuff in other threads, what type of glue do you use/recommend? the substrate here is hardboard. (I'm not going to cover up the maple frame).

Use any wood glue, like Elmer's or Titebond or any other brand. The process of sticking the veneer depends on the type you get. What I used was "raw" veneer, very thin (and cheap) with no backing, process described in my Firestone restoration thread down the page. Other kinds are self-stick or with a paper backing, follow mfr's. directions.

"Will this thread never die?" you ask.

Small update to the build log, and layout change to the site... After being shocked at veneer prices (this cabinet needs a LOT), I'm going to go with some oak I already have on hand...

I don't get any commission from these people, but I found this pretty cheap; it's what I used.

http://www.rockler.com/product.cfm?page=2214&filter=veneer

Yeah, I had a look at their site... the prices are much more reasonable than here (something like $19 per square meter vs $29 in store here)

Two problems though; the first is that shipping to Canada tacks on another $15 bucks, and the second is that the area I need to veneer is a bit more than is in 3 packs, so I'd have to get 4 (this is 10").

The second is that I'd like to avoid seams if I can, which 10" won't let me do... I'd need at least 24" which I already have on hand (as oak) and I'd rather use it than let it go to pot (It was wrapped in a newspaper from 1980!!)

I've been experimenting with some scrap pieces to get a feel for how it behaves with the glue (bought plenty!)

(My spare resistors also arrived today) ...so almost there!

Quick status update... Started veneering; what I found works best here (espcially because there are a lot of splits; I need something a little less "instant") is to glue it to the hardboard, and weight it down (45 kg of cat litter works well!)... Then after the glue has dried for a few hours, break out the iron and smooth out the bumps (if any).

Great tip, Reece- I never thought to re-activate the glue with heat; I knew it could be done with hide/fish glues, but not with plain 'ol PVA glue.

Hi everyone,

Unfortunately, all work on the radio is now on hold. Over the weekend, my father fell off a ladder while preparing a second-story window for painting. He suffered a major head injury, and the doctors say that the damage is so severe that there is no chance of recovery. We've spent the last two days nearby in the ICU.

I'd rather everyone knew than to leave you in the dark; we have incredibly supportive family and friends, and wish to thank them, and everyone else for their support.

I do intend to finish the radio (in his memory) as soon as I am able; he was very skilled with woodworking, and veneering the cabinet was the last thing he helped me with before the event. The radio is only about a decade younger than he was, but he took joy in my progress on the project, and I think it only fitting to do this.

I would ask that if you wish to communicate or express condolences that you do so via PM; he wouldn't have seen any sense in cluttering this thread or going off-topic.

Thank you again to everyone for their support; I only wish I could have given you all better news.

Back to work...

My father passed away peacefully last night, and at no point did he suffer.

Things are slowly getting back on track, and I find the cabinet work is rather relaxing.

I just finished putting on the last large pieces of veneer. The next step is to deal with any cracks and splits that are too large.

Yet another off the wall question:

This set (now) has external RCA input. Would it sound significantly different if I piped in a regular FM tuner versus a tube-based FM tuner? I've got a Pioneer F-50 AM/FM tuner (no amp, just RCA-out) which sounds nice thru my PC speakers. (Logitech X-530)

So sorry about your father, a tragedy. We never know what may happen to us.

You should be OK with your Pioneer tuner. What I would do first is plug the AC of both of them in and turn them on without connecting the audio jacks yet. See if you get any significant voltage (low AC volts range on meter) between the outer shell of the plug from the tuner to the outer shell of the jack on the Fleetwood. Try turning one AC plug over and recheck, ditto on the other AC plug. Choose the combination that gives the least voltage (if any.) Should only be just a handful of volts.

If it happened to be more than that, I might consider putting a .1 mfd cap in the shield line between the units.

I've only got to do half that, at most... the console has a polarized line cord on it per electroking's suggestion :)

I hadn't thought about the AC isolation, but good suggestion!

Edit: Just started varnishing the veneer. It looks incredible... Part of it is that well-aged wood doesn't need stain to get a deep natural colour... and this veneer has been exposed to air for _at least_ 30 years, and likely more.

Heh.. I ended up doing a "why knot" resistor replacement... There were a few left to replace that were iffy and I didn't have spares for... but then I had their solder knots untangled and figured "why not?" and replaced all of the other ones in that knot... leading to more knots... and so on.

A'right... Welcome to 3+ posts of me talking to myself :)

Anyhoo... just finishing up the underside of the cabinet lid. There were some large gaps in the veneer... Used an old trick I learned from my dad- take fine sawdust, mix with wood glue to make a fairly dry paste and _really_ _work_ it in to the splits. If you use sawdust from the same wood you're filling, then it matches the colour when you varnish it... just need to be careful to get rid of all excess or you'll have glue spots under the varnish.

Another question- Is it normal for the resistors to the radio tubes to get hot? I've got 2W jobbies in there now, (as on the schematic) and they get pretty warm... you can touch it for a few seconds but any more starts getting pretty uncomfortable.

Finally- did an adjustment on the trimmer for maximum reception-How long are those screws? it feels like it's about to fall out, so I backed it off a turn and left it at that.

A'right... Welcome to 3+ posts of me talking to myself :)

Anyhoo... just finishing up the underside of the cabinet lid. There were some large gaps in the veneer... Used an old trick I learned from my dad- take fine sawdust, mix with wood glue to make a fairly dry paste and _really_ _work_ it in to the splits. If you use sawdust from the same wood you're filling, then it matches the colour when you varnish it... just need to be careful to get rid of all excess or you'll have glue spots under the varnish.

Another question- Is it normal for the resistors to the radio tubes to get hot? I've got 2W jobbies in there now, (as on the schematic) and they get pretty warm... you can touch it for a few seconds but any more starts getting pretty uncomfortable.

Finally- did an adjustment on the trimmer for maximum reception-How long are those screws? it feels like it's about to fall out, so I backed it off a turn and left it at that.

The screws are not very long, maybe just 1/8-inch (about 3 mm) or so.
They just work by changing the curvature of a spring blade forming one
plate of the small variable capacitor. As for the 2-W resistors, just make
sure the voltage on them is within spec, and keep them suspended is free
air (even though it's inside the chassis) not pressed against some insulator
that will impede convection cooling. The usual rule of thumb regarding
resistors is to keep the actual dissipation below half the nominal
power rating. Good night.

I saw a guy sanding a floor do that once: after sanding, he gathered up some of the sanding dust and mixed it in a tray with shellac. Then he had an applicator sort of like a cloth "swiffer" that he mopped this all over the floor, filled the cracks. Being shellac, it dried fast. In half an hour he was ready to fine sand and varnish.

Doesn't sound right that you would have to back a trimmer out to the point of falling out. Normally they'd be somewhere in the tight to midrange of their travel. If this is C1A on the schematic on the first page of this post it ought to peak on a weak station at the high end of the band. The weaker the better, to avoid AVC action.

We're looking at about 38VAC with a fully grounded input (3-prong cord)... and about 6V with the tuner. I've put the (orange drop) cap in anyway.

Of course, I've got everything back in the cabinet, and this is the moment that the balance issue (nothing on the right channel) chooses to resurface. DAMMIT.

Time to hunt that down... I think it may be wiring... I hope we haven't lost a tube.

So sorry about your father, a tragedy. We never know what may happen to us.

You should be OK with your Pioneer tuner. What I would do first is plug the AC of both of them in and turn them on without connecting the audio jacks yet. See if you get any significant voltage (low AC volts range on meter) between the outer shell of the plug from the tuner to the outer shell of the jack on the Fleetwood. Try turning one AC plug over and recheck, ditto on the other AC plug. Choose the combination that gives the least voltage (if any.) Should only be just a handful of volts.

If it happened to be more than that, I might consider putting a .1 mfd cap in the shield line between the units.

Edit:
D'oh.. feel like an idiot. Nearly pulled the chassis (somewhat of a pain in this set b/c you have to hold it or it falls out when you take out the last screw... putting it back in is also a one-handed jobbie) before it occurred to me to double check the speaker wiring.

On the back of the set there's a terminal strip which has RCA outputs for external speakers (and hardware to sense their connection).

Each terminal strip has 2 connections. However, only ONE of these connections is actually connected to the amp output... the other is not connected. You can infer what happened when I re-wired the speakers. :bash: :withstpd:

Anyhoo... all is well now. Got 'er playing and it sounds great.

:beerchug: :guitar: :rockon:

Yes, I know that
:worthless:

so stay tuned. Pics coming tonight!

Update: Pictures uploading as I post.

After 11 pages, 155 posts, and 2470 views... WE'RE DONE!

a BIG thank you to everyone who helped bring this to fruition.

Hopefully I'll find another tube set and be back for more :)

If you've got questions or comments about anything, drop 'em below... I'll field them as I can.

Thanks again!

:yippy::beerchug::beer: