OK guys, now that I'm done with the Silvertone Combo unit it's time to start a new project. After wrestling that 24" tube and chassis I thought I'd go completely in the opposite direction.
I got this TV from the famous online auction site with a local pick up instead of shipping. It was part of an estate the auction house was taking care of. The pictures in the auction showed a clean and everything was there TV. When I went to pick it up, sure enough it was in very good condition, at least the cabinet was.
When I got home I slowly applied 6.3V to the CRT. We have glow. Whew! I know the CRT could still produce a lousy picture but that hurdle has been crossed. It sat waiting for me for most of the year.
As you can see, someone decided to mark up the chassis first with pencil and then with a Sharpie! Knucklehead. That what tape is used for. There is a corrosive something going on. Perhaps an electrolytic spewed out its guts. It seems to affect the steel parts only.
BTW, the serial number of this chassis is 208806. I didn't take any pictures of the cabinet yet. I'll get to that later.

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I have an original copy of Sams 62-16 along with the Riders info as a backup. I removed the CRT and put it away in a safe place. Then I removed the speaker assembly and covered the cone with cardboard. It was also put in a safe place.

As my usual customary procedure, I labeled all the resistors, capacitors, inductors, pots, etc according the Sams.

I then pulled each tube to be sure it was in the correct spot, cleaned it, tested it, and wrapped it in a paper towel and put away till needed. All the tubes tested good. Most were either Raytheon or RCA. The 35B5 audio output tube was a Ken-Rad. The 4 12SN7GT tube were all Raytheon with a date code of 9-18. Could be 9-13 though. The 25L6GT H.V. osc. tube had a date code of 8-48, and the 1B3GT H.V. rect. tube had a date of 8-52.

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I have the HV caps on order and will go to Mouser tomorrow to pick up the electrolytics. Then the fun begins.

Outstanding! Clean as a whistle. This is a classic.

The later '49 version, which that one is, had the shield under the speaker transformer. The '48's didn't and they got cooked by the heat of the tubes.
It's looking good! Those are a total classic. Not only really unusual looking, but historic, and they play very well to boot! I read that these were the first collectors item TV sets, that's why so many exists today.
Remember to always do a soft power-up with these. Unfortunately the scarce CRT takes jolt when they're turned-on the normal way, much like a pilot bulb in an old radio. I've used a Variac on mine since I first got it.

Couple of notes.

ARF has a thread where a TVS diode (basically a w way sense) is wired in parallel with the CRT heater and limits the voltage across the heater to it's designed value (more common cheap signal tubes take the hit instead). I'd highly recommend that option.

Second I've found that goof off or rubbing alcohol will take sharpie off of chassis metal.

Third enjoy your restoration.

Interesting way that you tune the channels. Much like a radio. Obviously there was no detent for the channels. Would this be a split sound design for the sound and video IF?

It is a 1949 TV-37U model.

When I got my electrolytic caps I picked up some TVS diodes too.

I don't think it is a split design. The sound pickoff comes at the Video amp tube. I forget what the proper name of that design is. Intercarrier?

I started on replacing the electrolytic caps tonight.

I decided not to re-stuff C1 and C3. Because it was easy to add a terminal strip for C1 and C3 was just wired in directly.

C1 is a double cap that has a 100uf and a 40uf cap both at 150 volts. I used a 100uf and a 47uf both at 250 volts and 10,000 hour 105C caps. I used a terminal strip to mount these.

C3 is a single 40uf 150 volt cap. I used a 47uf 250 volt cap like the one above.

I replace a 2 position terminal strip with a 3 position terminal strip and used that to mount C6. It was a 5uf 50 volt cap and was replaced with a 5.6uf 250 volt cap . The reason I used a 250 volt cap was that the 250 volt cap is more robust and less chance of getting damaged.

I cleaned, lubed, and polished R2 the Brightness pot.

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These things are just SO KEWL ! Mine has the green CRT, but it appears to be pretty strong & in decent shape... Would like to have the blue CRT, but I can live w/the Green one Dunno which one freaks people out more-The little Pilot, or my 10" Zenith Porthole... LOTSA fun to screw w/ Arrogant, know-it-all Millennial twits w/either one.. "There was TeeVee back then? Why ain't it Color ?!?"

Does anybody know if anyone has used a chassis mounted resistor to drop the mains from 124Vac to 117Vac? I have a nice 12 ohm 25W chassis mount resistor that would serve that purpose nicely. What do you think?

These things are just SO KEWL ! Mine has the green CRT, but it appears to be pretty strong & in decent shape... Would like to have the blue CRT, but I can live w/the Green one Dunno which one freaks people out more-The little Pilot, or my 10" Zenith Porthole... LOTSA fun to screw w/ Arrogant, know-it-all Millennial twits w/either one.. "There was TeeVee back then? Why ain't it Color ?!?"

You ought to play a loop of a radar screen showing a newkleer attack on the green one and a close up of of the window of a front load washer on the Zenith....Now THAT would really mess with people. :D

" Why ain't it color?"... Look here son this one is Green and green is a color!...you go out n find me a red one and some dichloric mirrors and we can make those sets show us all the color(s). :D

Hmmmmmm... Ain't thought of that 'un, Tom...

Beautiful set, I can't wait to see how it comes out. I've seen a few of these sets in my life, just never a working model.

Some progress over the last few days. I must say that I'm not impressed with the workmanship of the original factory build.

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I decided to redo the tuner and with the corrosion on the tuner I removed that section. I cleaned and lubed the tuners and did a recap. All ready to go back in at a later date.

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I finished the IF strip today. My HV caps should be in tomorrow so I can finish up the chassis without waiting on any orders.

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Oh, BTW, I have changed out 45 resistors so far. Only 9 have been in tolerance. 80% out-of tolerance, 20% in-tolerance.

I had the same experience with the resistors in the 2 sets that I have done. Worst by far of any set I have restored. One way that Pilot got to their $99.00 price point was by using the cheapest (worst quality) resistors their purchasing department could locate. They had a rough finish on them, so unlike the Allen-Bradley smooth finish.

Almost done. Need some .047 630V caps and to reinstall the tuner and change the 2 caps in the HV cage.

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OK Today I turned it on and I have a problem I'm hoping we can get it solved.

As you can see in the picture, it looks like severe vertical fold over. The Vertical height works and as shown is maxed out, and all the other controls work properly. While I wait for suggestions, I'm going over the Vertical circuit to see if I messed up a component or put it in the wrong place.

I'm using a 3RP1 right now. The CRT that came with the TV looks to be gassy and doesn't display a raster.

Thanks guys.

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Found the problem. I inserted a 4.7K instead of a 4.7M resistor. R96 in the Sams. On to alignment.

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Congratulations on getting it going!

Most excellent.

Watching this and decided to do the TVS diode mod. Got some and installed it as I read the post between the filaments of the 25Z6. Pins 2 and 7. Easy install. It flat lined the vertical output. No joy. Removing it brought the sweep back with no damage. What did I do wrong?

Sounds as if you limited the 25 volt heater of the 25Z6 to a little over 6 volts (or whatever the diode is designed for) likely killing B+ to the vertical circuit.
The diode needs to be installed accross the heater pins of the crt, not the rectifier. Pins 1,11 of v21, not pins 2,7 of v20.

jr

I posted a mistake and deleted it.

Jr. Makes sense. I used the other post instructions for the 25Z6 and will give the CRT version a try. Now back to our regularly scheduled post.

I'm going to add a retrace line blanking circuit to my TV-37. I see elsewhere of adding a 220K resistor inline with the CRT grid wire and then adding a 820pf 1KV cap at the resistor/CRT junction to pin #5 (plate) of the V. output tube. Connected to pin 5 of that tube is a .005 6Kv cap. Do I install the 820pf cap on the side of pin 5 of that 6kv cap?

Directly to pin 5.

jr

what crt pin are you putting the 220 k, then attaching a 820pf cap to the resistor then to pin 5 of the vert output tube, I ask because I have a pilot without the blanking circuit and I may do the same.

what crt pin are you putting the 220 k, then attaching a 820pf cap to the resistor then to pin 5 of the vert output tube, I ask because I have a pilot without the blanking circuit and I may do the same.
Pin 2 the G1 grid.

Thanks

May I ask how you came up with 820pf, would 1000pf work ?

http://www.videokarma.org/showthread.php?t=268971&highlight=pilot+tv+retrace

Wow, my big bad, lol, yes I already done it I looked back on my notes for when I restored it. It was such a small change other then the restoration it self so yes it's done and no lines ever since, lol. :scratch2:

Wow, my big bad, lol, yes I already done it I looked back on my notes for when I restored it. It was such a small change other then the restoration it self so yes it's done and no lines ever since, lol. :scratch2:

I thought you were loosing it! LOL!

Nice score Crist !
The Pilot has been at the top of my list of tv's to get for years now. Such a interesting set. Your work looks excellent, good job.

Nice score Crist !
The Pilot has been at the top of my list of tv's to get for years now. Such a interesting set. Your work looks excellent, good job.

Thank you.

Well, I just lost HV! The picture went dark over about 2 to 3 seconds. I changed out the 25L6 and the 1B3GT tubes but no joy. I ohmed out the coil and that's good. No signs of anything being burnt either.
Any suggestions?

Well, I just lost HV! The picture went dark over about 2 to 3 seconds. I changed out the 25L6 and the 1B3GT tubes but no joy. I ohmed out the coil and that's good. No signs of anything being burnt either.
Any suggestions?

First thing I'd do is check voltages on the HV osc and compare to the schematic. That should find something to point you in the right direction.

Well, I just lost HV! The picture went dark over about 2 to 3 seconds. I changed out the 25L6 and the 1B3GT tubes but no joy. I ohmed out the coil and that's good. No signs of anything being burnt either.
Any suggestions?

I noticed with these pilots that if you turn it on then off for whatever reason and turn it back on within a few seconds the hv won't come up . Wait 25 seconds and it will likely come back on. There is a mica pot on the side of the hv cage check that. Hv adjust . And yes I thought for a moment I was losing it too....

I noticed with these pilots that if you turn it on then off for whatever reason and turn it back on within a few seconds the hv won't come up . Wait 25 seconds and it will likely come back on. There is a mica pot on the side of the hv cage check that. Hv adjust . And yes I thought for a moment I was losing it too....

Tis the season for people to have too much on their minds and do things that make others think they are loosing it... I've already had a such a moment today.

Found it. It was the 35W4 tube went bad. Whew!

Did that 35w4 burn a hole threw the side of the plate.

Can anybody point me to solutions to the Vertical Linearity problems. Seems like I read somewhere to use a pot of 1M? instead of trying different resistors.

BTW, Sams says to switch out R59A to solve the problem. Mine never had a R59!

Thanks.

Use .02 uF film or 6 kV ceramic caps for vertical deflection coupling,
or .05 uf 3kV ceramic ones. These, of course, will bite you much worse than
0.005 uF ones.

If you have the Rider's vertical circuit with the two 1500 pF bridged feedback caps, switch to the Sams circuit.

That fixed mine.

If you adjust the picture to about 1/2 the vertical height, is it still non-linear?

jr

Wow, my big bad, lol, yes I already done it I looked back on my notes for when I restored it. It was such a small change other then the restoration it self so yes it's done and no lines ever since, lol. :scratch2:

I tired this and I ended up with more retrace lines! Any suggestions?

I'm going to stick with retrace line removal then concentrate on the V. linearity problem.

I'm going to stick with retrace line removal then concentrate on the V. linearity problem.

If the vertical sweep is distorted, the blanking pulse derived from it may also be distorted. If it were my set, I would concentrate on getting the vertical correct first. :scratch2:
Just a thought, I did not need retrace blanking added to my set, so I don’t have first hand knowledge.

jr

Ok. I have another TV-37 here and it is wired like the Sams. so I rewired this TV37 to be like the other set and Sams.
Still no joy.

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I agree fix whatever may be wrong with verticle first then do the retrace mod. My pilot had lines all over the screen but every one is gone after doing the mod.

OK. I'll work on the Vertical Linearity problem first.

OK. I'll work on the Vertical Linearity problem first.

Excellent, good move! I suspect that you may find it quickly.

Well I tried switching tube positions and still no joy. I used my other CRT and tired it away from the speaker and that didn't help either.

Do you have the hv cover on while trying it, because if you don't then you will have a lot of distorted lines from hv leaking to the crt.

Do you have the hv cover on while trying it, because if you don't then you will have a lot of distorted lines from hv leaking to the crt.

Yes, the HV cover is on and screwed to the chassis.

I brightened up your linearity picture so I could see it well.

Its really bad. Mine started out bad, but not anywhere near that bad.

Something is seriously wrong with the generation of the signals.

First make sure that the HV for the CRT is up to snuff with a reliable HV probe.

Next make sure that the HV voltage divider resistors are correct and not partially
shorting to ground. Note that the linearity is dependant on what is somewhat like
a current source from the HV chain. Be sure that that 0.002 uf cap on the focus
center wiper is OK. You might add another one from the top of the focus pot to
ground. That picture looks a bit out of focus ... that's an important symptom!


Then get out the oscilloscope with a 10 meg
probe and start snooping around. The waveforms at the plates of the two
video output sections should be reasonably linear and also important,
approximately equal size. If not, make sure that the B+ and B- voltages are
reasonably what the table says and that the voltage divider for the second stage
grid is right. Try different tubes. Wholesale parts replacement may be in order.

But first, get the HV and focus chain exactly right!

With my pilot I had small issues because of low B+ so I added a diode to the rectifier tube and that fixed the low voltage along with the other problems. Is your hv at least 2-2.5 kv ?

I was working on my Pilot yesterday to see why it always showed hum in the picture
and the horizontal sync broke up if the contrast was too high. It has always done this.
It turned out to be my mistake .. a 6BA6 with a very mild case of heater-cathode leakage
was in the last IF amp socket and a good 6AU6 was in the video amp socket. That's
backwards. Moving the 6AU6 and a new 6BA6 almost fixed that. The remaining hum
is probably capacitave from the series heater string.

I also needed to tweek the audio IF trap so I looked under the chassis.
My set, which has good linearity, is using two .02 uF 6 kV ceramic caps in parallel
for each vertical deflection plate coupling.

Fixed it. Ready for this. I adjusted the H. Hold and the severe bending at the top of the picture was gone.

However, the picture was still very dim. You see, I recapped my second TV-37 and that one had a lot brighter picture. Then I remembered that L17 has a 1N34 video diode that I never replaced. I pulled L17 and changed out the diode with a 1N34A, 2 resistors, and a 250pf mica cap. Reinstalled L17 and the picture was a lot brighter. I put my crosshatch generator on it and adjusted the vertical size, horizontal size and linearity, and picture centering. All is well.

Thanks to all for your suggestions.

Here are some pictures of the before and after L17.

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That's very interesting. Those old germanium diodes seem to develop internal resistance over time and apparently yours was leaking some DC offset onto the video amp grid, messing with sync and brightness. Anyhow good fix. :thmbsp:

Do I see a third resistor changed? To the left of the mica on pix 4 and 8 from the top.

Interesting way that you tune the channels. Much like a radio. Obviously there was no detent for the channels. Would this be a split sound design for the sound and video IF?

DuMont made a console TV in the early 1950s with the same type of tuner this set has. These tuners would receive all 13 VHF TV channels at the time (including now obsolete channel 1), and also the FM broadcast band between channels 6 and 7.

Do I see a third resistor changed? To the left of the mica on pix 4 and 8 from the top.

Just saw this. Yes on the third resistor.

DuMont made a console TV in the early 1950s with the same type of tuner this set has. These tuners would receive all 13 VHF TV channels at the time (including now obsolete channel 1), and also the FM broadcast band between channels 6 and 7.

Maybe a Mallory Inductuner? My Andrea has one and it works perfectly with zero attention paid to it.

John

Yes, Dumont, Stromberg Carlson, Andrea and others used a Mallory Inductuner in the late 40s. They phased them out in the early 1950s.

This set uses less complex and expensive variable capacitor.

Some SC sets and Crosleys were actually Dumonts in cabinets made to the spec of the badge being slapped on.