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Re[4]: JVC av-27920
Robert Posted Jan 16, 2006, in response to:Eric
Hello Eric
I do thankyou for the help,But I am going to have to give up soon,
as the board may have a problem with it that is above repairing.I have
checked the vertical ic on the pins and 1 is ground,2 is 13.2 should be 13.7
close enough,3 is 24.2 should be 25.6,4 is .8 right on the money,5 should be
.7 but have 1.3,6 which is the vcc you talked about is 25.0 right on the money,
7 should be 1.6v is .10.I have excellent sound,picture in the middle of the screen in the inch and a half is there.I have gone over the resistors and caps
again,even replaced any that might be questionalable.Zener was replaced.
Any suggestions would be appreciated,before I call it quits with this tv.
Thanks Rob
Reply
2 comments
Robert I apologize. I see the entire post now, didn't before. You have the Sams and have already replaced the Vertical Out IC.
Eric
Comment 1, Last comment
by Eric Jan 24, 2006
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
Comment 1, Last comment
by Robert Jan 17, 2006
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