View Full Version : Silvertone 7140


miniman82
02-22-2016, 05:46 PM
Here's a Silvertone roundie I saved recently. Gotta be a rare one, I've never heard of it before. Chassis seems CTC-4ish to me, with the giant hockey puck doorknob cap and HV shorting plug. All original Silvertone brand tubes which test good, so it can't have had a lot of hours on it. Cabinet is beat to hell and back, gonna be another veneer job just like the CTC-7 Ed now owns. That means this one has to wait for at least a year while I catch up on house payments, all my money goes there till further notice. Unless of course someone has a 15GP22 to sell... :D

http://miniman82.4t.com/images/Silvertone/front.JPG
http://miniman82.4t.com/images/Silvertone/chassis1.JPG
http://miniman82.4t.com/images/Silvertone/chassis2.JPG
http://miniman82.4t.com/images/Silvertone/chassis3.JPG
http://miniman82.4t.com/images/Silvertone/chassis4.JPG

miniman82
02-22-2016, 05:50 PM
Here's the Sams on it, Steve was nice enough to put it up on the ETF site.

http://earlytelevision.org/pdf/Silvertone-7140-sams-388-1.pdf

SwizzyMan
02-22-2016, 05:57 PM
Reminds me a lot of a 19CT1 with that bezel.

roundscreen
02-22-2016, 09:27 PM
That is one cool set. The metal shield over the front of the yoke, Looks like the ctc5 yoke. Is there a ground wire attached to it? What are you going to do with the grill cloth?

jr_tech
02-22-2016, 09:45 PM
528 is Warwick ?

jr

Tom9589
02-22-2016, 10:00 PM
Yep, 528 is Warwick.

Tom9589
02-22-2016, 10:02 PM
Is it missing an HV cage or did they just have all those tubes and the flyback out in the open?

old_tv_nut
02-22-2016, 10:45 PM
How's the CRT?
That looks like a unique mount / insulator boot / edge magnet setup.

ChrisW6ATV
02-22-2016, 11:14 PM
Very nice find!

Electronic M
02-23-2016, 01:50 AM
Wow, what an unusual design. Definately not a direct clone of a CTC-4. I wonder if any more examples of that chassis still exist.

Phil Nelson
02-23-2016, 02:30 AM
Definately not a direct clone of a CTC-4.Yes, it uses a different color demodulation method, for one. Not to mention the different physical layout. And what's with that vertical centering control -- a dual pot with a 500-mfd non-polarized electrolytic. This set should make a very interesting restoration story.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

miniman82
02-23-2016, 07:44 AM
Is it missing the HV cage, or did they just have all those tubes and the flyback out in the open?


It's missing, we searched the whole house looking for it but no luck. It's just a perforated steel box that covers the fly and horizontal related tubes, you can see it clearly in the full Sams. I only scanned the schematic info for ETF to upload, my computer can't handle large files for some reason. Probably time for an upgrade.


How's the CRT? That looks like a unique mount/insulator boot/edge magnet setup.


Wayne, the CRT tests very good but the base has seen better days. Probably going to have to load it up with sensor safe sillycone to shore it up, I'm too nervous to attempt surgury on a good AXP. The insulators around the tube are actually pretty close to what the Admiral Ambassador has, and I swear Anchor Co. had a monopoly on HV insulators back in the day- they made every single boot for every AXP set I have! lol

Wow, what an unusual design. Definately not a direct clone of a CTC-4. I wonder if any more examples of that chassis still exist.

This is the only one known according to ETF, but that doesn't mean there aren't more out there. Never seen a color set this early with the chassis around the tube like this, but seen it a lot with B&W stuff. It's about the same size/weight as the Admiral Ambassador that came from Canada, just with the circuits around the CRT instead of on a flat chassis.

Yes, it uses a different color demodulation method, for one. Not to mention the different physical layout. And what's with that vertical centering control -- a dual pot with a 500-mfd non-polarized electrolytic. This set should make a very interesting restoration story.


Right, I guess I just meant that it has the same doorknob and HV shorting plug so it has to have some borrowed parts at least.

Steve McVoy
02-23-2016, 08:32 AM
The 1954-55 Motorola color sets had a vertical color chassis, but not really around the CRT.

http://www.earlytelevision.org/motorola_19ck2.html

DavGoodlin
02-23-2016, 08:57 AM
Very interesting indeed! No PC boards either.
This will be fun to follow when you post the play by play.

benman94
02-23-2016, 01:22 PM
The circuit is very similar to the licensee circuit Hoffman used. Should be a pretty decent performer when it's all buttoned up! Very nice set :)

Hagstar
02-23-2016, 05:20 PM
Totes jelly! (totally jealous) I love Sears for this kind of bizarre old and new engineering mix. I collect their radios and a typical thing is a modern front end with octal tubes mated to a bank of completely outdated tubes like type 45s in a late 30s set. I just love the wrapped chassis- it must also make the set much more balanced. My CTC-4 Seville is hideously unbalanced- heavy in front and chassis-side of course.

John H.

Username1
02-23-2016, 08:08 PM
Totes jelly! (totally jealous) I love Sears for this kind of bizarre old and new engineering mix. I collect their radios and a typical thing is a modern front end with octal tubes mated to a bank of completely outdated tubes like type 45s in a late 30s set. I just love the wrapped chassis- it must also make the set much more balanced. My CTC-4 Seville is hideously unbalanced- heavy in front and chassis-side of course.

John H.

Very happy for you ! I have a Sears B&W set I got a few weeks ago, 17" tube
based portable, and all the tunes are original also. Also a Wells ID numbered
tv. My set is like two our family had when I was a kid. We also had never had
to replace any of the tubes..... Maybe WG designed sets more under the tubes
max current - and they lived a lot longer..... For this set just look at the
H and V outputs..... from the pdf posted...... I'm getting more respect for
WG when I look at the insides of my set, and this color set.

Looking forward to seeing this one come back to life.....

Nice find, hope there are more out there.....

I wish there were more out there about the companies design criteria, and
in this case about the circuit design, if it was licensed from someone else,
etc.....

.

dieseljeep
02-23-2016, 08:44 PM
Very happy for you ! I have a Sears B&W set I got a few weeks ago, 17" tube
based portable, and all the tunes are original also. Also a Wells ID numbered
tv. My set is like two our family had when I was a kid. We also had never had
to replace any of the tubes..... Maybe WG designed sets more under the tubes
max current - and they lived a lot longer..... For this set just look at the
H and V outputs..... from the pdf posted...... I'm getting more respect for
WG when I look at the insides of my set, and this color set.

Looking forward to seeing this one come back to life.....

Nice find, hope there are more out there.....

I wish there were more out there about the companies design criteria, and
in this case about the circuit design, if it was licensed from someone else,
etc.....

.
The set shown is a Warwick product, Sears source # 528.
Wells Gardner was never interested in building products for Sears. Most firms claimed that the Sears buyers were too cut-throat and there was little room for a decent profit margin. Sears had an interest in Warwick from the mid-50's.

Username1
02-23-2016, 08:55 PM
The set shown is a Warwick product, Sears source # 528.
Wells Gardner was never interested in building products for Sears. Most firms claimed that the Sears buyers were too cut-throat and there was little room for a decent profit margin. Sears had an interest in Warwick from the mid-50's.

I know, Sears was as bad as Walmart from what I have read ! But unwritten
is ~ Did Sears expect Wells to stand behind the design as far as excessive
warranty work on all their sets....? Did Wells have to carefully balance their
profit with whatever Sears may have tried to stick them with if the set
were to have a chronic problem leading from a design goof....?

I think it was 60 minutes that did a story on Rubbermaid and their dealings
with Walmart when they got into WM. Sounded to me like Sears buying up
companies they starved while working on exclusive deals.....

OOPS I think I got my Wells, and Warwick mixed up.... At any rate, read as
"The company Sears Sourced for the tv..." Sorry....

.

Hagstar
02-23-2016, 09:15 PM
The set shown is a Warwick product, Sears source # 528.
Wells Gardner was never interested in building products for Sears. Most firms claimed that the Sears buyers were too cut-throat and there was little room for a decent profit margin. Sears had an interest in Warwick from the mid-50's.

Instead Wells Gardner built a huge amount of sets for Montgomery Wards- all the "62" preface sets.

John H.

SwizzyMan
02-23-2016, 09:18 PM
Didn't know warwick would even be capable of its own color set this early. Also it seems by '58 no one would even use the 21ax anymore. Wasn't the 21cy introduced by then?

Kevin Kuehn
02-23-2016, 09:44 PM
Maybe Warwick got a deal on a truckload of obsolete 21ax's. It's a very interesting chassis layout. I'm really not too crazy about the styling of the cabinet, but it'd still fun to have such a rare set. Looking forward to seeing this one restored.

jr_tech
02-23-2016, 09:47 PM
Didn't know warwick would even be capable of its own color set this early. Also it seems by '58 no one would even use the 21ax anymore. Wasn't the 21cy introduced by then?

Yes... according to Keller " The Cathode Ray Tube" page 180, 1957 was the first year for the 21CYP22... I am surprised to see a 21AXP22 in a 1958 set... perhaps Warwick got a deal on remaining AXPs? :scratch2:

jr

SwizzyMan
02-23-2016, 10:11 PM
Either that or they just wanted to use up possible remaining stocks.

Username1
02-23-2016, 11:52 PM
I think it was no different on the commercial end as the retail end..... While new tv's
came out that were all solid state, you could get a few year old tube design for
$10. - $20. less....

I'm sure they were still cranking out 21AX's somewhere....

What ya got for a date code on that tube miniman82 ????

.

Steve D.
02-24-2016, 01:03 AM
The SAMS folder for this Silvertone is dated Feb. 1958. SAMS was always published months after the release date of the TV it depicted. The Silvertone was produced some time earlier in 1957. No reason to believe there was a shortage of available 21AX tubes in 1957. Wondering if this set showed up in the Christmas 1957 Sears Catalog?

-Steve D.

miniman82
02-24-2016, 10:27 AM
What ya got for a date code on that tube miniman?

No idea, the base is mangled. The pins are all there, but the chunk that should have the date on it is missing.

BigDavesTV
02-24-2016, 12:26 PM
An excellent and rare find/save, in my opinion, congratulations, miniman82! I especially love to see pictures of sets that I have never seen, much less even knew existed, and this is certainly one of those, for me!

zenithfan1
03-11-2016, 04:13 PM
That is one awesome set!

miniman82
04-23-2016, 10:44 PM
Finally mostly nearly almost done unpacking the TV related stuff, that means it's time for an update! :D


Got some time this weekend to pull the chassis back out of the cabinet (no CRT's died in the back of the U-Haul truck on the way here thank GOD!), so I put it on the bench and brought it up with the variac. First I removed the horizontal and vertical deflection tubes, so I could reform the power supply caps. That went well and nothing got hot, so next I scoped the horizontal oscillator to make sure a waveform was there to drive the HO tube (it was), so I put all the tubes back in and brought it up...


Nothing.

It was absolutely dead.

Started digging, and there's voltage to the vertical oscillator. Strange it should be running, wonder if there's bad caps in it. Twiddled the LIN and height controls because sometimes after sitting there's high resistance in the elements that can keep it from working and with a BANG and a SNAP, the vertical oscillator started running. This was a smokers set unfortunately and it's very dirty and dusty, yet another chassis I'll end up pulling all the pots out of for a scrab and deoxit. Dammit. Well for now I had vertical sweep, which on this set is powered by B+ not boost, so I moved on.

Still no horizontal, though I can hear it sort of trying to spool up- at least when the dirty HO tube's socket doesn't decide to not power the filaments. Note to self, schedule socket cleaning...grrr...

Looked at the HV wiring on the 3B2 and 1X2 focus rectifier, and it's toasty. All cracked and mangled. Possibly horizontal is getting dragged down by HV leakage? Took me 3 hours to get the HV cup apart on this because like a CTC-4, there's a giant doorknob built into the bottom of it. The tin can lid of it has to come off the bottom first, and it was soldered together. Took a torch to get that apart. Finally get to the guts of it only to discover that the rectifier socket had been replaced with a ceramic one at some point in its history, and it's way too big for the little metal plate it's mounted to. Now it's all deformed, and I gotta pound it back into shape.

Get the old socket removed and the pie plate straightened out, but I don't have any octal sockets that fit in the smaller than normal hole. Piss, this just ain't my day. Thankfully I had won an Ebay auction for a replacement one not long ago, so I stuck that in with some new Belden 40kv anode wire. Let's try this again: only 5kv...

OK, not good. Either the flyback is bad, or I got some kinda serious unknown drain on HV somewhere. I already knew the CRT tested good from when I picked it up, so I knew that wasn't the problem.

Oh BTW, I discovered at some point that the selenium LV rectifiers were past their prime, so B+ was seriously sagging as soon as the tubes started drawing current from the power supply. Those got replaced with silicon along with some new electrolytic caps, I'll add series resistance to it later.

Only other thing that can drag down HV is the shunt tube, a 6BK4. So I disconnected the CRT anode lead and the plate cap of the 6BK4 and try one more time before assuming the worst- Bingo, 29kv shows up on my meter! OK cool the 6BK4 grid is probably too high, so I put a meter on it. Sure enough, it's at 210 when it should be around 135 VDC. HV pot doesn't do anything either, so I trace it out.

The 6BK4's grid receives its marching orders from a HV bleeder string that starts on the focus rectifier, goes through some very high megohm resistors, then the HV pot gets a chance to shunt some of that voltage to ground, then there's a 1-meg to the 6BK4 grid. So logically if the pot does nothing and the tube is stuck fully on, there's gotta be an open somewhere either on the pot or the 1-meg going to the grid. Read through the pot and it actually came back nice and smooth with the correct resistance, so I look at the 1-meg going to the grid- it's drifted up to 14 meg! :sigh:

After replacing the 1-meg grid resistor on the 6BK4 I now had a full bright raster with controllable HV, so I set the pot to around 23kv and called it good. Now all the major parts have been verified as working, so I can sit down after the ETF meet and start ordering all the caps this thing is going to need to be reliable.

Also need to build a new HV cage for it, we searched the house it was in but didn't locate it.

That being the case, I pulled the CRT and took a shot of the backside of the chassis. CRT is a Sylvania made tube according to the EIA code (if that's what the 312 on the label is anyway), and has the original Silvertone brand label on the bell. First color set I've ever owned to still have all of it's original tubes in it, gotta be some kinda miracle. Enjoy the pics. :thmbsp:

http://miniman82.4t.com/images/Silvertone/chassis5.JPG

Here's a link to a high-res shot of the chassis: http://miniman82.4t.com/images/Silvertone/image1.JPG

The CRT:

http://miniman82.4t.com/images/Silvertone/CRT.JPG

ohohyodafarted
04-24-2016, 12:13 AM
Congrats on getting it going Nick. The chassis reminds me a lot of MOTO chassis, a gobbldygook hodgepodge nightmare. Not nice and orderly like a RCA. God knows why they work at all, but they do.

snelson903
04-24-2016, 06:10 AM
that is a awesome set, look's all original to .

dieseljeep
04-24-2016, 01:55 PM
According to the code-date stamp on the label, the CRT is from 1960. Sears Silvertone replacement CRT's were always sourced by Sylvania.
The original CRT was probably an RCA.
The original owner might've had a maintenance agreement from Sears. That would explain all the Silvertone branded tubes. :scratch2:

miniman82
04-24-2016, 02:05 PM
Thanks Bob, it is a mess isn't it? lol

Dave, I assume you're looking at the numbers '016' on the label? I guess that means 16th week of 1960, so it probably is a replacement. What makes you think the original was an RCA? The other Sears set I got from the same house is just like this one, all original and untouched (CRT replacement aside). The owner was very proud of his Sears brand items, and probably had service agreements on all of it.

Next task will be carefully replacing the CRT base with a new one, don't suppose anyone has a spare Silvetone base for me? That's gotta be a rare item, if it even exists. Probably just put a generic one on there, anyone got one with no markings that could be donated to the cause? I'll look for a brightener at the museum, but don't know if they have one.

MRX37
04-24-2016, 02:39 PM
Ya know, well this might not be available in your case but with 3D printers and laser scanners, it's possible to replicate things like bases and other parts for these TV's.

Wouldn't it be neat to download a file with the 3D information for, say a knob that you're missing, then pay a few bucks for a 3D printer to make one?

Eric H
04-24-2016, 02:56 PM
I do have a Silvertone base I saved from a junk tube, however it's a 1961 date code and has an RCA 274 EIA code.
It's yours if you want it.

miniman82
04-24-2016, 05:10 PM
Man, vk comes through again! I'll take it, how much you need to change vet shipping and whatnot to 20634?

Thanks Eric!

Eric H
04-24-2016, 05:36 PM
P.M. sent.

miniman82
04-24-2016, 05:47 PM
Thanks Eric, I love this place!

dieseljeep
04-25-2016, 10:04 AM
According to the code-date stamp on the label, the CRT is from 1960. Sears Silvertone replacement CRT's were always sourced by Sylvania.
The original CRT was probably an RCA.
The original owner might've had a maintenance agreement from Sears. That would explain all the Silvertone branded tubes. :scratch2:

It seems, RCA made all the 21AX CRT's. Sylvania might've just regunned them or if it was a new tube, Sylvania bought it from RCA and relabeled it.

miniman82
04-25-2016, 10:27 AM
To add to the mystery, this tube has no neck weld which would tend to indicate it was rebuilt. But the base did have a 274 EIA code on it which is RCA.

dieseljeep
04-25-2016, 12:16 PM
To add to the mystery, this tube has no neck weld which would tend to indicate it was rebuilt. But the base did have a 274 EIA code on it which is RCA.

Every early color set that I've seen, that used a 21AX CRT, that CRT had a EIA 274 on it. That was a GE, Hoffman, Motorola and an Admiral. It had the OEM brand name on it, with a 274 EIA.
IIRC, Sylvania was the main supplier to Sears for their replacement tubes. The OEM tubes were made by several different Mfg's. :yes:

miniman82
06-03-2016, 05:40 PM
Chassis is now moved to the designated resto bench in the garage, where recapping can take place. I've already stuffed the can 'lytics and replaced a few wax tubulars, but there are many more discrete 'lytics and other assorted caps that need to be rooted out before I fire it up again. I also need to figure out how exactly to connect the horizontal deflection coils to the test jig: the chassis has a center tapped setup where the center tap is cap coupled back to the flyback, while the test jig doesn't have a center tap at all. I can probably do one of two things, either leave the CT out or add one to the jig's yoke and see what happens. If I can't get it going, I'll just have to wait till cap replacement is done then put the CRT back in.

Eric: the replacement base worked flawlessly, thank you very much. I was even able to use a brass wire wheel to remove the 21FJP22 mark on it, it disappeared leaving shiny black plastic behind and you can't even tell it was ever replaced. :thmbsp:

Here's where I'm currently at:


http://miniman82.4t.com/images/Silvertone/image7.JPG

miniman82
06-03-2016, 05:45 PM
Here's the new base on the CRT.

http://miniman82.4t.com/images/Silvertone/image8.JPG

Eric H
06-03-2016, 05:59 PM
Here's the new base on the CRT.



It looks great, glad it worked out well. :thmbsp::thmbsp:

BigDavesTV
06-24-2016, 12:07 PM
Tube socket replacement looks great, anxious to see pic's of the set running someday!

miniman82
06-24-2016, 01:13 PM
Chassis resto got interrupted by some paid work, I had to repair a trio of CTC-15 clones for a guy up in NJ. Those are done now, but I took a minute to tool around with a Packard Bell roundie chassis someone gave me for free. Once that's fixed, which is just an AGC fault after recap, the Silvertone goes back on the bench to get completed.

Steve D.
06-27-2016, 12:46 AM
From the Chicago Tribune April 15, 1956. Blowup from ad shows Sears Model 7140 in Mahogany.

-Steve D.

miniman82
06-27-2016, 02:41 AM
Nice! PB chassis is done now, back to work on this thing!

zenithfan1
06-29-2016, 12:04 AM
:lurk:

truetone36
07-10-2016, 04:12 PM
Just curious- how did a Packard-Bell end up in your neck of the woods?

miniman82
07-11-2016, 11:34 AM
I think it was actually in NC, but drug up to Fredricsburg where I got it. Guy that had it used the cabinet for something else, yeah he's one of those guys...

truetone36
07-11-2016, 08:59 PM
I've seen what those guys do. I have a bookcase that was made using a Philco TV-123 cabinet. When I asked about the guts I was told they went to the dump:sigh:.

matt99
07-11-2016, 11:07 PM
I've seen what those guys do. I have a bookcase that was made using a Philco TV-123 cabinet. When I asked about the guts I was told they went to the dump:sigh:.

How much of the cabinet do you have? Shame about the original guts, but it could be a fun project to fit a later roundie chassis in the tv123 cabinet.

Electronic M
07-11-2016, 11:57 PM
I've seen what those guys do. I have a bookcase that was made using a Philco TV-123 cabinet. When I asked about the guts I was told they went to the dump:sigh:.

Bob Galanter (ohohyodafarted) has one with a terrible cabinet...He may want to buy yours.

miniman82
07-12-2016, 08:06 AM
One of mine (the large 123 console) is pretty nasty too, looks like it sat in a basement most of its life. Bottom plywood board is going to need replacement, it's missing the back (have a template to make one), and the finish is shot. The table model set isn't as bad, but will still need going through to be up to snuff.

Speaking of cabinets, I took the Silvertone to a local place to have it gone through. Place looks like it will be able to take care of me, and I gave them the lowdown on how to deal with bad photofinish. They are going to install new ribbon mahogany for me, replace the broken speaker board, and put new grill cloth on it from AES. AES had a cloth that was very close to the original, I got lucky. Price was a little more than I wanted to pay, but I'd really rather not do it again myself because it was such a pain.

Here's the place I took it to: http://www.schoenbauer.com/

truetone36
07-12-2016, 10:40 PM
I have the complete cabinet, but it's rough. It has veneer issues and some of the glued joints are a bit loose. It had been sitting in a shed for several years by the time I found it.

miniman82
07-13-2016, 07:56 AM
Got any spare knobs?

truetone36
07-13-2016, 09:18 PM
Knobs for what set?

miniman82
07-17-2016, 08:41 PM
The TV-123! I think I'm only short one or maybe two of the small ones, but that set is gonna wait around for a long time till I get to it anyway. The table model 123 takes precedence before that one, once this here Silvertone is done of course.


Update: I think I finally have all the capacitors replaced on the Silvertone chassis, it was a real pain in the butt since everything is really crammed in there. Also seems like this thing was built on a Friday near shift change if you know what I mean, lots of excessive solder on joints, components not routed in what I would call an intelligent manner, and even a capacitor goof from the factory. It seems whoever built this got confused about which cap to put where, because a non-polar horizontal centering cap got installed where a normal 'lytic should have been and the polarized 'lytic wound up in the horizontal centering spot. The caps in question were C13 (10uf polar in the horizontal oscillator) and C12 on the H-cent wiper to ground.



http://miniman82.4t.com/images/Silvertone/image9.JPG

http://miniman82.4t.com/images/Silvertone/image10.JPG


Next issue I'm going to have is, the H-yoke connections in this chassis are center tapped and my test jig is not. Anyone see an issue leaving the center tap off for testing, or would it not deflect properly? Schematic is below, wire in question comes off tap #2 on the flyback.

http://www.earlytelevision.org/pdf/silvertone_7138_sams_388-1.pdf


Reason it would be nice to be able to use the jig is the CRT on this thing completely obscures the chassis components, so if there's an issue after recap and I stick the tube back in it has to come right back out and that's a PITA on this thing. Would be nice to be able to debug it, then put the jug back in.

miniman82
07-23-2016, 10:20 PM
In the end I made an extension cable for the original yoke and put it in the jig. That wasn't easy, since the original yoke has this odd plug that looks octal but has 9 pins. Fortunately I had such a plug in my box of test jig cables, so I was able to bring it up that way. Raster came up but I had no video, so I went through all the tubes in the chassis. Found a dead 6BR8 in the tuner and a dead 6AH6 which is the 4th IF tube. New ones are on their way, hopefully once those are in we will see some color bars.

miniman82
07-28-2016, 04:54 PM
Lookie what we got here, cabinet guys came through today in fine style. I think I'll use them for all my future restorations, they did a very good job on this. Here's the website, in case anyone in the area was wondering: http://schoenbauer.com/

Ignore the wires puking out the top of the speaker mounting board, I already fixed that. The speakers are both shot anyhow, I need a 6x9 and a little tweeter as well (4" I assume). Grill cloth was sourced from AES, they had something very similar to the original stuff.

http://miniman82.4t.com/images/Silvertone/image11.JPG


I think the tubes for the chassis came in the mail today as well, which means that by the weekend I should be able to dive back into the chassis and figure out why I'm not getting a signal through the front end. Wish me luck! :thmbsp:

Steve D.
07-28-2016, 08:42 PM
Fantastic job on the cabinet & the grill cloth. Looking forward to your progress reports.

-Steve D.

Electronic M
07-28-2016, 11:57 PM
Ooh, dat's purdy!

zenithfan1
08-01-2016, 04:58 AM
That looks pretty sweet!

miniman82
08-02-2016, 02:29 PM
Yet more late RCA chassis to deal with before I get back to this thing, and a random Maggie that has contrast issues. Never ends, I tell ya!

Kevin Kuehn
08-02-2016, 02:56 PM
I need a 6x9 and a little tweeter as well (4" I assume).


Think these might work? The 6x9 measures 3.5 ohms dc, the tweeter 12 ohms. I think the 6x9 actually came out of an RCA set, as it has the crossover cap still on it. There's a couple of little "oops" holes around the rim of the 6x9.

http://i452.photobucket.com/albums/qq245/Kuehn/VK%20Pictures/TV20speakers20001_zpstcu8hdpi.jpg?t=1470077519

http://i452.photobucket.com/albums/qq245/Kuehn/VK%20Pictures/TV20speakers20003_zpsp7jfbj9u.jpg?t=1470077624

miniman82
08-03-2016, 08:02 PM
Sure, I'll PM my address if you want to donate them to the cause. Just measured the voice coil on the high frequency speaker here, and it's 12 ohms as well.

MRX37
08-03-2016, 10:45 PM
a 6x9 that measures around 3.5 ohms? If originality didn't matter, then, like you have about a billion car speakers to choose from many of which might even sound better.

Hagstar
08-04-2016, 04:40 PM
They did a nice job on that cabinet. Pay whatever they ask and bring a sixpack. Give them more time than they suggest. They don't make shops like that anymore.

John H.

Dave A
08-04-2016, 09:42 PM
I have had great luck with Liquid Tape as a patch for minor tears in speakers as long as the ends touch. It stays flexible forever. And in my misguided youth, I have been know to treat a cone with some oily spray I had on hand to remoisturize it. Use at your own risk.

Phil Nelson
08-05-2016, 01:12 AM
You can also repair speaker tears with tea bag paper and flexible glue (such as fabric glue).

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

miniman82
08-05-2016, 03:18 PM
I've always used single ply toilet tissue and nail polish, but the lacquer can get old and brittle so it's not the best long term solution.

Looks like they didn't completely spray a portion of the safety glass sill, think I can make up for it with some toning lacquer?

miniman82
02-19-2017, 06:15 PM
Finally found some time to monkey with this some more, been a long time coming! Special thanks to Cliff Benham, for locating a nice set of NOS speakers to replace the ones that were not salvageable. The high frequency one in particular was an oddball, some odd fraction between a 4 and 5" speaker.

As you may recall, before I was able to get a raster on screen but not much else. I decided I wasn't getting anywhere trying to mess with it having HV and everything else running since it's quite hazardous poking around the chassis with wires going everywhere, so I took the test rig back apart and set it up to receive OTA signals while observing the cathode wave forms with a scope- sans vertical and horizontal sections.

I didn't get anything but noise at first, then I remembered that's normal with the horizontal section off because there's no AGC. So I dragged the alignment rig over so I could use the negative supply that's built into it, and set it for -4.5v like the schematic says. Still nothing. At this point I took a break, because there's no use fighting yourself when you're at an impasse. Is the tuner dead? Sure hope not, I hate tuners!

When I came back a few jack and cokes calmer, I fired it up again and verified there was still nothing. Double checked the connections to make sure I hadn't missed anything, and I hadn't. Time to verify voltages in the IF pin to pin, to see if they match the schematic. First IF and second IF tubes were good, but the third had high plate and screen voltages- bingo, it's not drawing any current!

Took the 6DC6 third IF tube out and tested it, and it was fine on the tube checker. So I put it back in and still had nothing, but that's when I noticed the shield that goes around it was still stone cold despite being on for more than 10 minutes. A ha! Must be the filament supply going to that socket... no, there's voltage there as well. Dirty socket? Yep, worked the tube back and forth and eventually it lit up and a staircase appeared on the scope!

I should have guessed that was the problem, since the horizontal output tube won't light unless you futz with it either. So this chassis still needs a really good socket cleaning before it's done, I'll make a mental note. I decided to go for broke at this point and see if something would show up on screen, but I didn't want to mess with the test jig anymore. What to do? Well I didn't want to risk the original CRT either, so I shoved a glass tube into the chassis, made all the connections and hit the switch: at last, a luma staircase appeared on screen!

:banana:

The picture wasn't locked vertically or horizontally so I had to adjust the horizontal slug, but then a nice staircase was up and stable. At this point I think it's time to spritz some deoxit into all the controls and work them, reassemble the chassis and CRT combo and see what happens. Hopefully I'll be able to post something resembling a proper picture next time!

BigDavesTV
02-20-2017, 12:34 PM
Good progress! Looking forward to more and hopefully soon, screen shots!

miniman82
04-22-2017, 04:32 PM
Had to take a business trip out west, but before I left I got the cabinet most of the way reassembled. I was going to just swap out the glass for one of the repop ones I had made because it was really nasty and I didn't feel like cleaning it, but it wound up being a slightly different size than what RCA used so I was forced to bust out the simple green and Windex. Also shined up the sliver parts, came out pretty good.

http://miniman82.4t.com/images/Silvertone/cabassembled.JPG



Here's the speaker board, they sound pretty good! High frequency driver is a more modern type, unsure if the exposed magnet will affect the screen purity. If so, I'll make a shield for it out of thin steel.

http://miniman82.4t.com/images/Silvertone/speakers.JPG


No time for anything else prior to the convention, I'll finish the chassis evaluation and clean up the knobs when I get back.


Side note: this chassis doesn't have an H-lin coil in it, the damper just goes to B+. Any harm in trying to put one in there? Schematic calls for 215ma on the output tube, I read 232ma on my meter with line voltage at 117 and B+ reading exactly what it should. I'd like to get closer to, if not under, 200ma to be on the safe side.

SpaceAge
04-22-2017, 08:25 PM
Looks great. Rotated ur pic ;)
http://imgur.com/y8q3f7E.jpg