Pilot TV-37 Restoration
 

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?

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.

Pin 2 the G1 grid.

Thanks

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

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.

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?

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.