[TechAssist] RCA-CTC169AM,chass-f31221wn-32''

From: <hartstv@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Date: Thu, 24 Jul 2003 18:56:51 -0300

This direct view 32'' unit has me baffeled.Orginally came in with the HOT 
shorted.Replaced with an OEM 2SD1885.Everything else was ok so fired it up.The 
HV was 38.5KV,too hi,so took the chass out to bench test.Turned it on without a 
yoke plugged in & I think that's when my problems started.Q4802 smoked in the 
pin cct.Replaced it & plugged a yoke to the set.Now my smps won't start.Pin 16 
reads 8.5vdc then slowly goes up to 10.5vdc & then starts going back down to 
8.5v.So changed all the normal parts for this smps,ie,the 
U4101,C4102,4,8,Q4101.Did not help.Replaced the infamous CR4118.Checked or 
replaced both LM311 in the vert & pin cct;also C4403,CR4401,CR4402.Again no 
go.Checked or replaced all trans in the PWM cct,Q4405,6,7,8,9.Same results;the 
regulator is trying to start but keeps going up/down from 8.5v to 10.5v.Raw B+ 
is solid at 165vdc,no ripple.All these tests were done with HOT collector 
lifted.I have checked all my tips for this unit,& I know there's a ton of them 
but can't find the problem.I have changed so many parts too numereous to 
mention,ie caps,diodes,transistors but I'm stumped.Any assistance would be 
greatly appreciated or if someone would be so kind to email a pdf for this 
brute.The only print I have is a profax for the 27'' set.BTY i also checked all 
transistors in the Q4300 & Q4700 series.........TIA............
Don of HARTS-TVCR-ASC
9 Robert St,Oromocto,NB,Canada,E2V3N2
Tel-506-357-9785,Fax-506-357-6010
hartstv@xxxxxxxxxxx



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Follow-Ups:
- [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32''
  - From: Larry E.

[TechAssist] RCA-CTC169AM,chass-f31221wn-32''

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