|
need info on 1960 RCA kcs132k chassis
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.
|