RCA in INDIANA

[7"estatdef]

What if you used a seprate filament trans for the crt and used the center tap for the cathode connection?
Terry

[edison64]

Hmmmmm, didntr think of that I'll try that.

[edison64]

Ok, I am sure I am not doing something right. Could you please describe how to connect the transformer???? Also, all the crt pins are resoldered with no change.

[jeyurkon]

The transformer would be useful if there was a heater to cathode short. I believe edison64 said that the cathode is open, in which case the transformer doesn't help.

Checking the solder connection at the base would be the first step.

If that's not the problem and there is absolutely no emission even with raised heater voltage, then it could be an open cathode. Then it might be worth trying to weld the cathode. Some CRT testers such as the Sencore CR31A can be used to attempt to re-weld the cathode.

John

[Tubejunke]

The chassis on the old RCA's of that era are more or less the same whether a 10", or a12" crt is installed. Just a different mounting configuration, and I'm sure some electrical differences as far as HV and deflection go. NOW, I have never seen a 16" set with a metal/glass crt, however, I would say that even those sets are similar. The big difference that comes to my mind is the way the second anode connects to a metal/glass crt. Even that could be reconfigured. I guess it's all in how bad you want something to work. A 10BP4 will not fill that viewing area. That might actually be your biggest hurdle. Perhaps make a new border out of wood........

[edison64]

Ok great news! broke out the "big BK" and noticed that it had a test for a 17gp4 the tube still showed open k, after thumbing through the manual, found a way to weld the cath. tried the first step, nothing.. went to the strongest setting, tapped the neck and... spark spark sizzzzzzzz the weld took!! Now the tube tested nearly dead, about 50 out of a 1000, let it cook over night, now reads about 100, with nothing to lose, i cooked it at 8.3 v 4 hrs, now reads about 200. according to bk, the tube needed to be re activated, because of the welding process, used the reactivate feature and now the tube actualy reads 975. still no raster, but shows a splotch when you first turn it on, suspect hv problem, now at least i can start recapping. will keep you posted.

[John Marinello]

If your HV is low, turning DOWN the brightness may get you a picture.

[zenithfan1]

Good job on that tube. That can be a real bummer when the crt is shot. It's fun when you think it's shot then bring it back to life. I hope that one holds for 'ya.

[edison64]

Update: after checking the tubes found about half questionable or bad, replaced them and then went into the hv cage... WOW the cap came right off the 6gb6, replaced that and then the lead broke or was burnt off, fixed that... Now here is the kicker... the 1b3 had a huge crack!!! the elements and wires inside this tube are rusted and corroded!!!!! replaced that, now I am thinking how long ago did this happen. put the cage back and noticed the anode wire was loose and the end was clipped to the plastic mask!!!!! resoldered that and made sure there was connection to crt bell. And now the smoke test, after about 20 seconds I was rewarded with a nice btight horiz line with about 3/4 in deflection.... yeah!! yeah!! I will post pix when it's done but I still need to recap,Does anyone know where I can find a Sams, I cant find one anywhere the # is suposed to be 109-11

[bgadow]

I'll check for the Sams tonight-got lots of duplicates so chances are good I have it.

[bgadow]

Yep, I have it. I try to get $5 (includes postage) and if that sounds okay, just send me your address and off it goes.