drh4683
03-16-2008, 10:26 PM
ITs a rare occurance for a yoke to fail. Im looking for a deflection yoke for a 1970 Zenith 12A12C52 chassis p/n 95-2780 which crosses to a thordarson Y-137. This yoke is only used on these chassis and not too many of them exist today:
12A12C52
12A13C52
12B13C52
12B14C52
Some corrosion accumulated on the windings which lead to arcing between various windings and now its burnt and I lost HV because of it.
Any help is greatly appriciated. I'll really be surprized if Moyer has it. Yokes are rare and moyer generally doesnt have zenith parts available. I contacted them though. Just looking for other possibilitys out there to get this set going.
kx250rider
03-17-2008, 12:21 PM
NOT rare at all for that yoke to fail! I replaced many yokes on that chassis series. Is it keystoned? Sorry no longer have any yokes on hand, and I don't have any source for any of those yokes. I always used to save them when junking any of those particular sets since they were often needed. I bet somebody else did the same, and has one :)
Charles
Chad Hauris
03-17-2008, 07:35 PM
I put an admiral 25" set deflection yoke on an RCA CTC53 that had a burned yoke and it worked really well...if you are at a last ditch effort with no exact replacement you might be surprised how well a similar type yoke would work.
drh4683
03-17-2008, 07:45 PM
I got very lucky. The good news came back from Moyer and they actually have a thordarson Y-137.
Its interesting to note as to how this yoke failed. You are all probably familiar with the goop that accumulates around the HV anode cup on the CRT on Zeniths that use the translucent yellow HV cup. It breaks down and becomes sticky residue and it leaks down the CRT. This set got so bad that the oil went down the neck of the CRT and onto the windings. It broke down the resin coating on the copper and corroaded. This eventually caused HV to arc and then carbon built up and snowballed into a nice large burn though of this particular section of the windings.
I got this set from carmine and talked to him about the problem. We discussed what the problem was that could have caused it and he suggested this possibility. Upon inspection, that was definitly it. The yoke apparently was up against the CRT which lead to this oil getting on the windings causing the failure. So watch out for those oily looking CRT's and check the yokes!
I didnt know yokes were this common on Zeniths of this type. Anything in particular as to why else they were known for failure?