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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Degauss relay clicks 3 times when power is turned on. No stand-by
voltages. Raw B+ at 170 volts. Removed H.O.T , stand- by voltages come back., but regulated B+ at Cr106 160 volts. Raw B+ still 170 volts. Disconnected reg. B+ at pin 3 of flyback transformer ,no difference. Could it be IC14101, oscillator for Q101? Voltages on IC seem to be normal. |
#2
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Is the HOT shorted? How big is it? Some 32/36" RCA
with "three strikes, your'e out", could be flyback. Ctc197 flyback is 237506. Look here. Sky. http://www.freelists.org/archives/te.../msg01741.html |
#3
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HOT tested same as new with diode test. 36" RCa.
Skype_man wrote: Is the HOT shorted? How big is it? Some 32/36" RCA with "three strikes, your'e out", could be flyback. Ctc197 flyback is 237506. Look here. Sky. http://www.freelists.org/archives/te.../msg01741.html |
#4
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Scope the collector of the HOT when you attempt a start. A badly
distorted waveform will indicate a shorted flyback John |
#5
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CTC197 notorious for bad flyback. I put a meter on the collector of the
horiz output. Read AC voltage at turn on, then put a HV probe on the anode wire and read the HV at turn on. A good working set has about 300vac rms on the output, 30kv on the anode. Of course you need a good meter with min/max setting to really do this. The flyback if bad will load down AC on the collector, but the basic readings will still be usable. For example if you read 150vac at turn on, but only 2kv on your anode, you know the flyback is bad or the yoke is bad or the CRT has no vacuum or you have a shorted diode ect, off the flyback. Check the diodes, unplug the yoke and the CRT board and see if HV increases. If not, bad flyback. CTC197 not one of the better sets RCA has made. Flyback probably on factory back order, always is. |
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