Hallicrafters T-54 Restoration

[Jon F]

This set I bought on eBay about a month ago, I'm getting to start working on it. Metal cabinet needs to be re-finished, but I am putting that off until the end.

The 7JP4 tested good, and all of the tubes are also tested good. I also did about half of the recap job so far, I have a decent raster, but no sound(other than hum) or image at all.

I also replaced the selenium rect. with a 1N4007. I did not add an additional resistor in series, since for some reason there was already an additional 28ohm resistor in series before the selenium(in addition to the 18ohm stock part on the schematic) Maybe someone replaced the selenium in the past with a different part # or they were trying to bring the B+ down? Where is the best place to measure the B+ on this set?

[Jon F]

And here's where it stands now:

[ChrisW6ATV]

It is nice to see a raster on that set. Good luck with the rest of the project.

[Jon F]

Attached to pin #6 of the socket for the 6H6(pin 6 not used on 6H6 tube) one of the wires is disconnected from its destination. The schematic is giving me a headache, mainly because this pin is being used as a junction instead of being easily trackable if it was an active pin on the tube.

Can someone with a T-54 chassis look at the picture attached and let me know what, if anything, this insulated wire should be attached to? I am pretty sure it was detached when I got the set, as this image is from before I recapped the set.

[John Folsom]

While I don't have a T54 handy, you should be able to unambiguously identify the other end of your dangling wire, and also the other wire or component tied to pin 6 of the 6H6. Then you will know with certainty where the wire goes.

BTW, I would use the Riders schematic posted on the Early Television website, as these have fewer errors than the Sams schematics. Good luck!

[prkohlwey]

I took a pic with the red alligator clips on where the wire is going on mine. I hope this helps. there is also 2 caps coming off of pin 6.

[Jon F]

Originally Posted by prkohlwey

I took a pic with the red alligator clips on where the wire is going on mine. I hope this helps. there is also 2 caps coming off of pin 6.

Thanks! The wire you pointed out with the alligator clips I already have connected on my set. This is an additional insulated wire. I only have 1 cap coming off pin 6, .05uF. I also have a cap off pin 7, .1uF.

There are 4 wires connected to pin 6:

-.05uF cap to GND
-insulated wire going to terminal strip(shown by alligator clips in your pic)
-560kohm resistor going to another terminal strip adjacent to 6H6
-insulated wire disconnected that I can't figure out.

[BigDavesTV]

I have the wood cabinet version of that set IIRC, model 506? Someday I've gotta try to finish that one, I once had it working with a raster and halfway decent picture, but I put it aside, that was about 20 years ago! I imagine I'd probably have to re-cap it again, somewhat, and bring AC up very slowly on my variac. I haven't had to buy any HV Caps (the 6Kv Caps for the Electrostat Deflection Circuit), in so long, I wonder where to get them, now! Back when I first got this set going, the caps weren't too hard to find then. I also have an old 7" Motorola that needs restoration, well maybe someday!

[Jon F]

I got the .047 6000V caps from allied electronics, the rest from justradios.

http://www.alliedelec.com/search/pro...x?SKU=70006915

[pearsonk]

Jon, I'm doing a T54 now and was wondering if your replacement .047@6000
was used to replace the .03@6000, [shown on Sam's, Vert. sweep to crt pins # 10 & 11].
Sam's is for the 6au6 IF and I think Riders schematic is for the octal IF layout. My T54, with 6au6's in IF strip, uses .03@6000.
Your pics appear to show 6au6's in the IF.
My question is: Does it matter if I use .047@6000 instead of .03@6000?

Mine is actually the 505 [T54 in the wood cabinet], 9-48 date.

[Jon F]

Duplicate post

[Jon F]

Originally Posted by pearsonk

Jon, I'm doing a T54 now and was wondering if your replacement .047@6000
was used to replace the .03@6000, [shown on Sam's, Vert. sweep to crt pins # 10 & 11].
Sam's is for the 6au6 IF and I think Riders schematic is for the octal IF layout. My T54, with 6au6's in IF strip, uses .03@6000.
Your pics appear to show 6au6's in the IF.
My question is: Does it matter if I use .047@6000 instead of .03@6000?

Mine is actually the 505 [T54 in the wood cabinet], 9-48 date.

Sorry I never replied, my set originally had .047 mfd @ 6000V caps so that's what I used for replacement. My set uses 6au6 but the rest of the chassis matches closer to the octal set per the sams. (I have both SAMs sets for comparison )

[pearsonk]

Thanks for the reply Jon. Seems there was a change of values, even with
the 6au6 IF. Still wondering if the change was to: .03 -or- to: .047.
My date stamp was 9-49 [on bottom of cabinet]. If you have a date stamp, that would give us a clue. Probably does not matter, but sometimes values
were changed to improve performance, sometimes just because.
Mine did have .03, and that is what I have on order.

[Sandy G]

Awrite !! The "Raymond Loewy" Hallicrafters ! Great to see another one brought back to life !

[marty59]

There's a reason why all the pots mount on insulators! They can have some potential voltages on them so it's good to keep the knobs on them too.

And, there can be an issue with the HV transformer when it gets warm the set may lose high voltage. Use some screen mesh material for the cage top and you can mount a small fan to it if needed.