need info on 1960 RCA kcs132k chassis

[robert1]

Hi All
a friend of mine recently gave me a RCA 21 inch console that was in near new condition. it was his fathers set & it was stored in a dry basement since the mid-seventies. his dad said that the set quit working just before he moved it to the basement. now, it is over here & i am working on it. what i found when i pulled the back was the H.O tube has gone to air & that there was a crack in the glass just above the base. i replaced the tube with a N.O.S 6DQ6, checked the 6CG7 horizontal osc tube to make sure that it was ok, and powered it up. i have no high voltage, the horizontal frequency is too low (i can hear the high frequency), & the horizontal hold control does not change the frequency at all.
however, after five miniutes of leaving it on, the H.O. tube does not show any signs of redplating & it does not get too hot too fast.
i pulled the chassis, gave a visual look at all of the components around the horizontal output & damper tube & did not find any burned resistors. i took my V.T.V.M & checked the resistors in the grid drive circuit of the 6DQ6 & found them to be ok. i did a power-up & checked the voltage on the control grid of the 6DQ6 & it was running at negative 15vdc.
i removed the plate cap off of the 6DQ6 & checked the B+ voltage, which was running at 235 VDC.

i do not have a schematic for this chassis & i was wondering if someone here might tell me at least what the proper voltages are if they have the service information.

today, i did some more voltage checking & here is what i found.
i removed the plate cap off of the H.O. tube & checked the B+ off the 5U4 rectifier & got a reading of 260 VDC. i could also hear the vertical output transformer working.

with the plate cap on, when i first apply power to the chassis, the B+ voltage taken off the 5U4 drops down from 260 v to 215 volts (after the tubes warm up) and then rises to 225 when the "ringing" starts from the H.O. transformer.
i also notice that the 5U4 puts off substantially more heat with the plate cap on then with it off. thats when powered up for 5 mins. to me, that's an indication of the H.O. circuit drawing too much current.
also, i taken a voltage reading off of the cathode of the 6AU4 damper & only got a reading of 200 volts.
i guess there is no B+ Boost.

everything seem to point to a bad flyback transformer, however, the flyback appears to be in very good condition. there is no wax drippage & the tire is not warped or distorted. there is no apparent sign of damage.
same as the yoke, there is no sign of corrosion or any other problem.

what i am asking is if someone here in VideoKarma may have any service literature & possibly even a spare H.O.transformer for this set. it is too nice to junk out.

[bgadow]

Robert,
Wished I'd read this in the other thread...there is a good chance I have the schematic, I'll look tonight and let you know.

Have you replaced any capacitors? As I recall, they were still using "black beauties" at that time-notorious for going bad. They were probably okay when this set was stored in the 70s but are mostly shot now. If it were mine I would replace them all and then see where things stood. If they have already been replaced, that will mean some more indepth troubleshooting.

[robert1]

Originally Posted by bgadow

Robert,
Wished I'd read this in the other thread...there is a good chance I have the schematic, I'll look tonight and let you know.

i appreciate that if you would do that for me.

Originally Posted by bgadow

Have you replaced any capacitors? As I recall, they were still using "black beauties" at that time-notorious for going bad. They were probably okay when this set was stored in the 70s but are mostly shot now. If it were mine I would replace them all and then see where things stood. If they have already been replaced, that will mean some more indepth troubleshooting.

the first thing i did when i pulled this chassis out of the set was take my V.T.V.M & checked all of the resistors & capacitors associated with that circuit for any that were out of spec.
all of the resistors checked out fine as they did not drift out of spec.
i was surprised because i was expecting to see those Black beauty capacitors, but what i found were Sprague Orange drops, Mallory PVC & ceramic disk capacitors, which none of them were shorted or leaking.

[bgadow]

I think '60 was about the time they changed over to the newer style caps. I've had orange drops go bad but not very often. Sounds like you are on the right track.

I do have a spare copy of that Sams Photofact. If you send me a PM with your address I'll get it in the mail. I only ask that you cover my postage, if you don't mind.

[robert1]

i sent you a pm.

last night, i was digging through my junk that was buried under my bench & stumbled across a Eico 944 Flyback-yoke tester. i am currently working on it & i will use it to verify if the flyback is bad when i finish working on it.