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Re[5]: JVC av-27920
Eric Posted Jan 16, 2006, in response to:Robert
Robert, I sent you the Data Sheet for the LA7832. Don't like the low voltage on the Pump Up Pin 7. I know you checked and replaced any suspect caps. Did you actually replace C424 (100uF 35V)? If not I would do it. IMO something is loading down Pin 7. I assume you're working from Sams 4080. Notice that Pin 7 also feeds to Base of Q702 feeding to Micro. Maybe Q702 has a problem? Did you scope the input and output of the Vertical Out IC? If you don't have a scope use a good quality DVM. If you do use a scope of course use an isolation transformer.
How about C402 feeding vertical ramp signal back to IC201 pin 24. Also notice Yoke Return feeds to Micro Pin 3. I don't remember your original post. Have you replaced the Vertical Out IC? Hang in there. Take your time and be patient. If you need the Sams, let me know.
Good Luck,
Eric
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1 comment
Hello
Yup checked that those to.Q702 4.78 volts,.1. At pin 2 4.5v. R708 both sides shows 4.78v. Pin 24 shows 2.12v. I have replaced two vertical ics
LA7832 just incase one was bad.Replaced c424 twice incase.From Q702 to pin 7
on la7832 .1.I agree with you the problem seems to be pin 7 of the vertical ic,
I do not have the 1.6v I should have but where to go from here I think is a little above my head.Just to make sure I am reading the schematics correctly,
the 1.6v is to come out of pin 7.If that is the case there is something wrong there.If the 1.6v is to come to pin 7 there may be a problem in the line that my meter is not capable of detecting.I will wait to hear from you,and thanks again. Rob
Comment 1, Last comment
by Robert Jan 17, 2006
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