1939 RCA TRK12 scored

[Electronic M]

So a long time collecting goal of mine has been reached...I finally own a pre-war TV and it's exactly the model I had been shooting for. The TRK-12 is IMO a good "I only need to have one pre-war TV" set. It's most common of the pre-war US sets so it's most affordable/attainable and has the largest CRT of any of the ones with good production numbers and stylish ontop of that. So it's easy to see why I wanted it.

I was tipped off to this set (and Estes Auctions switching platforms) by a thread on ARF, and ended up winning it for $850. https://antiqueradios.com/forums/vie...p?f=3&t=427003

The following weekend (back on Saturday) me and my Dad drove out to pick it up. I got about 4 hours of sleep the night before partially from excitement partially from having to leave quite early to be there early enough to meet the auctioners schedule. By pure coincidence on the way the town we stopped for lunch at had a huge car show that I got a look at while eating. After dismantling the loose radio mask, CRT and TV PS chassis from the cabinet for transport I went over to a local friends place to buy a fully chrome cabinet Zenith CCII, drove for a couple of hours grabbed dinner and tagged teamed Dad into the drivers seat so I could check the CRT on the highway...The tube had bad base pin solder so I had to worry about an open heater until Sunday. Idid sort of expect a solder issue, but you never feel good about such an educated guess until you truly know.





Looking the set over it appears to be fairly complete. The left top prop is missing as are some of the pushbuttons for the radio. The ones I have are VERY shrunk as somewhat is the radio bezel.... Otherwise it's very complete. The cabinet is in interesting condition. The lacquer is still in really nice shape (ignoring a few scratches) to the point that it would be a Howard's job if it hadn't been stored by previous owners in a way that moisture has turned it into a glue and veneer job...The bottom chassis shelf has delaminated and warped to the point that I need to make a new one (seems doable), the top back board that the lid hinge connects to is popped out of it's joints with the sides, and just about all the front veneer on the left side of the grille has delaminated and is partially missing (this will be interesting to fix).

For those who have never seen a picture of a GE forecaster and a RCA TRK12 in the same room before.










On Sunday I managed to restore heater continuity by soldering the socket pins and achieved a poorly executed test. The 12AP4 is an unusual tube with a 2.5A 2.5V heater, and it's not in the setup chart of my B&K 466...That wasn't a big deal as 98% of CRTs are tested the same as a 10BP4 (ignoring heater settings) by the 466. What was a big deal is that my B&K has had an intermittent in its own heater circuit and those caused enough resistance to give me a high bad range emissions reading.... Enough to make me relieved it wasn't dead, but not to make me completely happy... However my sketchy beater DMM was telling me that the heater voltage was low, and on Monday I came back with my trusted fluke, flipped it to the base heater pins and adjusted the heater rheostat of the B&K to get exactly 2.5V at the CRT base (instead of the 1.8V my beater DMM earlier indicated). The results are NOS levels of emission. Part of me is skeptical (and worried about ion burn) because of the darkened G1 cup, but I'm just going to be happy until I can get the chassis working to know more accurately what it'll do.


I need to spruce up and off load some other sets first, but my priority will be to get the cabinet shored up and presentable, though I have half a mind to try the variac on the radio and if it goes well maybe the TV and that might happen first if I do it at all.

[Yamamaya42]

Ohh fun! one of those early sets with the lethal HV circuit!

[TV-collector]

Hi Tom!
Congrats to your big deal!
You are a big-shot that you were able to win this set for a bargain price,
away from all the collectors who had the cash to knock you out.

I had a few years ago the same kind of luck, as I won a 10" Sparton mirror-in-lid console.
Because I am in Germany without internet at home, I had to left a high bid
at central european daytime and had to hope, that nobody bid me out.
Yes, I had this luck, I won it for small money (seen with the eyes of a european
collector), because that auction house is not well-known like ebay.
What I have seen in the next morning in my office.

When this picture tube will work under typical voltages, the emission will rise.
I just powered up an early 70s TV set, which was places for decades inside a massy home.
It was so dirty, that I decided to part it out, just because its low value and
bad condition.
In the beginning the screen was closeby dark. After about 10 minutes the picture (snow) became brighter and brighter.

Great that your set "lives" now among all your other TV sets.

BUT, question:
I see your National-Panasonic VCR. I have the same as a european version,
bought that new back in summer 1981. Price was back then about 2200,- Deutsch Marks! Awful lot of money!

I would like to buy an american RF-converter (Ch: 3/4) of it.
Just this model!
If you or any other reader has one, or know how to find one, please let me know!

Good luck with the resto, keep us updated! I love to follow your reports

Regards,
TV-collector

[Electronic M]

Originally Posted by Yamamaya42

Ohh fun! one of those early sets with the lethal HV circuit!

Yeah, I'm going to be extra careful around that (plan is to avoid touching underchassis or the HV wiring while powered)... Especially given in the last two months while working on my Dumont RA-103 I forgot it had the audio out transformer on the speaker that was left in the cabinet and after successfully accidentally running it as an OTL amp with a modern speaker for a while accidentally completed the output tubes plate path across my chest reconnecting a speaker lead...It didn't injure me (theoretically it should have killed me) but definitely reminded me that some things should be minded better.

Originally Posted by TV-collector

Hi Tom!
Congrats to your big deal!
You are a big-shot that you were able to win this set for a bargain price,
away from all the collectors who had the cash to knock you out.

I had a few years ago the same kind of luck, as I won a 10" Sparton mirror-in-lid console.
Because I am in Germany without internet at home, I had to left a high bid
at central european daytime and had to hope, that nobody bid me out.
Yes, I had this luck, I won it for small money (seen with the eyes of a european
collector), because that auction house is not well-known like ebay.
What I have seen in the next morning in my office.

When this picture tube will work under typical voltages, the emission will rise.
I just powered up an early 70s TV set, which was places for decades inside a massy home.
It was so dirty, that I decided to part it out, just because its low value and
bad condition.
In the beginning the screen was closeby dark. After about 10 minutes the picture (snow) became brighter and brighter.

Great that your set "lives" now among all your other TV sets.

BUT, question:
I see your National-Panasonic VCR. I have the same as a european version,
bought that new back in summer 1981. Price was back then about 2200,- Deutsch Marks! Awful lot of money!

I would like to buy an american RF-converter (Ch: 3/4) of it.
Just this model!
If you or any other reader has one, or know how to find one, please let me know!

Good luck with the resto, keep us updated! I love to follow your reports

Regards,
TV-collector

Thanks for the kind words.

With regards to the VCR I bought that on the trip last weekend too. I've been searching for a knob tuned VHS top loader for years and don't plan on selling any part of it...Sorry.
Now that I have that Panasonic made Magnavox I can say I have every VHS deck I need in my collection and stop actively looking for more.

[Yamamaya42]

http://suzaku.live-evil.org/servi2.jpg

my left index finger is STILL healing from where i caught it on the sharp wire wrap point for 390v A for vertical linearity/height.

[Electronic M]

Originally Posted by Yamamaya42

http://suzaku.live-evil.org/servi2.jpg

my left index finger is STILL healing from where i caught it on the sharp wire wrap point for 390v A for vertical linearity/height.

Ouch! Sort of reminds me of RF burns from horizontal output tubes...If you ever get one you'll have a small blackened crater in your skin as a souvenir until it heals....Ask me how I know.

[dtvmcdonald]

Replace the HV wire on the TRK12. It may look OK but its isn't ... I got bit right through it, a half-inch away. Luckily the inertia of my arm broke the arc. I thought I was being careful.

Good luck with the radio ... that tuning mechanism is a disaster just waiting 80 years to happen. Its a good radio though.

[old_coot88]

Originally Posted by Electronic M

Ouch! Sort of reminds me of RF burns from horizontal output tubes...If you ever get one you'll have a small blackened crater in your skin as a souvenir until it heals....Ask me how I know.

Nothin' like an RF burn from a transmission line. You never know it's happening till you smell the hide burning.

[Electronic M]

Originally Posted by dtvmcdonald

Replace the HV wire on the TRK12. It may look OK but its isn't ... I got bit right through it, a half-inch away. Luckily the inertia of my arm broke the arc. I thought I was being careful.

Good luck with the radio ... that tuning mechanism is a disaster just waiting 80 years to happen. Its a good radio though.

Interesting.
I'll have to see if I can get shoelace spaghetti to fit over a modern 40KV HV wire, or maybe use modern reproduction cloth covered automotive spark plug wire...When it comes to rare sets like this I kind of have to have inside the back look like it's all original to be happy.

Now I'm more interested in the radio than I was.

Originally Posted by old_coot88

Nothin' like an RF burn from a transmission line. You never know it's happening till you smell the hide burning.

Interesting.... Horizontal Output Plate caps have enough DC on them that you immediately you're being bit on top of the burn. I guess I'm lucky I haven't RF burned myself on other sources.

[dieseljeep]

Originally Posted by Yamamaya42

Ohh fun! one of those early sets with the lethal HV circuit!

I was looking at the specs for the 2V3G, HV rectifier! It has a 5 amp filament @2.5 volts. It must run really hot!
I have an old Allied catalogue from 1952 and the tube was still available!
Tom: What socket did you use to test the 12AP4 CRT?
The cabinet is going to take a lot a restoration, but not impossible!

[Electronic M]

Originally Posted by dieseljeep

I was looking at the specs for the 2V3G, HV rectifier! It has a 5 amp filament @2.5 volts. It must run really hot!
I have an old Allied catalogue from 1952 and the tube was still available!
Tom: What socket did you use to test the 12AP4 CRT?
The cabinet is going to take a lot a restoration, but not impossible!

Wow, that rect tube is an oddball.
These sets could be adjusted to run on post war NTSC, and some owners even installed 13CH tuners so I'm not surprised people used them into the 50s.
If I wanted to test the CRT regularly I would use a 6-pin socket such as what a type 41 audio output uses as a CRT test socket since that style base is what the 12AP4 uses.... However since I wasn't sure until I saw it, and I had already made my own universal adapter I just used my universal adapter.
My universal adapter is basically a base from a dud 10BP4 with labeled color coded alligator clip leads soldered to the heater, K, G1 and G2 pins... I've used that adapter to check 15GP22s, a 12AP4 and other tubes when I don't have the right adapter but can find the datasheet to figure out pinout connection.

The sad part is a cabinet in good shape with a postwar TV hacked in went for $100 at the ETF...If I hadn't stopped bidding as I didn't want to waste space on something without it's original chassis I'd have been able to quickly make 1 nice set out of 2...

[dieseljeep]

Originally Posted by Electronic M

Wow, that rect tube is an oddball.
These sets could be adjusted to run on post war NTSC, and some owners even installed 13CH tuners so I'm not surprised people used them into the 50s.
If I wanted to test the CRT regularly I would use a 6-pin socket such as what a type 41 audio output uses as a CRT test socket since that style base is what the 12AP4 uses.... However since I wasn't sure until I saw it, and I had already made my own universal adapter I just used my universal adapter.
My universal adapter is basically a base from a dud 10BP4 with labeled color coded alligator clip leads soldered to the heater, K, G1 and G2 pins... I've used that adapter to check 15GP22s, a 12AP4 and other tubes when I don't have the right adapter but can find the datasheet to figure out pinout connection.

The sad part is a cabinet in good shape with a postwar TV hacked in went for $100 at the ETF...If I hadn't stopped bidding as I didn't want to waste space on something without it's original chassis I'd have been able to quickly make 1 nice set out of 2...

Maybe, you can contact the buyer of that set and make him an offer he can't refuse! It depends on how bad the cabinet has been altered and the overall condition!

[Tube TV]

Wow that's the nicest score I've heard of in a long time.

[Chris K]

Just gorgeous. OMG what an incredible find! Respect it and cherish it!

[dieseljeep]

Originally Posted by Electronic M

Wow, that rect tube is an oddball.
These sets could be adjusted to run on post war NTSC, and some owners even installed 13CH tuners so I'm not surprised people used them into the 50s.
If I wanted to test the CRT regularly I would use a 6-pin socket such as what a type 41 audio output uses as a CRT test socket since that style base is what the 12AP4 uses.... However since I wasn't sure until I saw it, and I had already made my own universal adapter I just used my universal adapter.
My universal adapter is basically a base from a dud 10BP4 with labeled color coded alligator clip leads soldered to the heater, K, G1 and G2 pins... I've used that adapter to check 15GP22s, a 12AP4 and other tubes when I don't have the right adapter but can find the datasheet to figure out pinout connection.

The sad part is a cabinet in good shape with a postwar TV hacked in went for $100 at the ETF...If I hadn't stopped bidding as I didn't want to waste space on something without it's original chassis I'd have been able to quickly make 1 nice set out of 2...

I seen a better picture of the CRT on the other website. It looks like a real skinny neck. As noted before, the CRT looks like a post-war replacement.