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CTC197 typical FBT symptom but FB rings ok

M

Michael

Jan 1, 1970
0
RCA F35676MB, CTC197CD, ser 649560677, mfr Dec 1996.

Have you had one of the CTC197 FBT failures where a ring test shows good but
the flyback is shorting or arcing internally only under full power?

This set has the "four strikes you're out" symptoms of a bad FBT reported in
this group in the past.

Power supply seems okay - in standby have 144 V, plus the lower voltages and
regulation appears good. When the power is turned on, the 144 drops to
about 100 V each time the set trys to fire up, then returns to 144 or so
back at standby.

In previous postings this symptom has been diagnosed as a faulty flyback and
most reported that changing the transformer fixed the problem. However,
this flyback rings good, and the yoke winding also show no apparent fault.
The HOT is okay.

I'm wondering if the CTC197 problems with the FBTs that were repaired by
replacement in the past were confirmed with a ring tester, or if the
failures showed up only when the HV comes up, as it might be in this case.
 
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