1939 RCA TRK12 scored

[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!

[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.

[Electronic M]

Originally Posted by Tube TV

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

Originally Posted by Chris K

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

Thanks. I feel really honored and lucky to have it.
It's been driving me nuts holding off on working on it. The last 2 weeks I've had to focus on my daily driver OTL tube amp (regular use stuff is top priority) that I designed and built back in college. After 9 years of service the power switch failed and when I opened it up to fix that I found it needed a bunch of other stuff redone. Basically where that amp has to live due to space constraints in my AV closet it bakes it's self into malfunction every few years. All the output heater wiring (a fair portion is buried behind transformers), and many of the caps were baked... I finally got it to a state where I could test it last night. I'm hoping I can get the output bias supply voltage issues sorted (may have a failed regulator) and get it back into service tonight, then get back to my regularly scheduled TV shenanigans tomorrow night.

Originally Posted by dieseljeep

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!

I tried that before picking up the TRK12 since the guy who got the other one is in that direction. He wants $1K for a cabinet that I'd have to replace the radio and TV control face plates boards on...That would involve removing the lid and the back top board that the lid hinge connects to...At that point the only difference in work making my cabinet as nice is making a new bottom chassis shelf (some drill and jigsaw action, glue, screw and paint) and some veneer patches. I just can't justify 1K that ought to go into the "buy a house already fund" on a cabinet that also needs work. I can probably make my cabinet nice myself for under a hundred dollars of materials, and a weekend worth of labor.

Originally Posted by dieseljeep

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.

Hopefully there were some good advances in the technology in the post war ones.

[dieseljeep]

Originally Posted by Electronic M

Thanks. I feel really honored and lucky to have it.
It's been driving me nuts holding off on working on it. The last 2 weeks I've had to focus on my daily driver OTL tube amp (regular use stuff is top priority) that I designed and built back in college. After 9 years of service the power switch failed and when I opened it up to fix that I found it needed a bunch of other stuff redone. Basically where that amp has to live due to space constraints in my AV closet it bakes it's self into malfunction every few years. All the output heater wiring (a fair portion is buried behind transformers), and many of the caps were baked... I finally got it to a state where I could test it last night. I'm hoping I can get the output bias supply voltage issues sorted (may have a failed regulator) and get it back into service tonight, then get back to my regularly scheduled TV shenanigans tomorrow night.



I tried that before picking up the TRK12 since the guy who got the other one is in that direction. He wants $1K for a cabinet that I'd have to replace the radio and TV control face plates boards on...That would involve removing the lid and the back top board that the lid hinge connects to...At that point the only difference in work making my cabinet as nice is making a new bottom chassis shelf (some drill and jigsaw action, glue, screw and paint) and some veneer patches. I just can't justify 1K that ought to go into the "buy a house already fund" on a cabinet that also needs work. I can probably make my cabinet nice myself for under a hundred dollars of materials, and a weekend worth of labor.



Hopefully there were some good advances in the technology in the post war ones.

I was looking through the old Allied catalogs and the CRT was available till 1950!