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JVC TV too hot,....vertical.

D

Dani

Jan 1, 1970
0
AV-27850, dead, repair vertical: LA 7832, 100 uf 35 volt cap,
75 volt zener, R 542 fusible resistor. Other caps check ok
with cap checker. Set runs fine, but LA 7832 gets quite hot.
Did I miss something?
 
M

Mark D. Zacharias

Jan 1, 1970
0
Dani said:
AV-27850, dead, repair vertical: LA 7832, 100 uf 35 volt cap,
75 volt zener, R 542 fusible resistor. Other caps check ok
with cap checker. Set runs fine, but LA 7832 gets quite hot.
Did I miss something?

Are you sure you changed the correct (boost) capacitor? I agree 100 uF at 35
volts is a typical boost cap value - but this sure seems like a boost cap
problem. Could the B+ be too high?

Mark Z.
 
B

Bill S.

Jan 1, 1970
0
AV-27850, dead, repair vertical: LA 7832, 100 uf 35 volt cap,
75 volt zener, R 542 fusible resistor. Other caps check ok
with cap checker. Set runs fine, but LA 7832 gets quite hot.
Did I miss something?

These do tend to run hot, and I wonder if the no-fins steel heat
sink was adequate to start with. But having said that, check the
vertical supply cap also. If the flyback capacitor doesn't have
a good stiff supply to charge against, you won't get enough boost
voltage for the IC to work efficiently. I recently had the same
model bounce on me, replaced everything the second time around,
even the caps that checked good, played it several days to make
sure, crossed my fingers and shipped it. So far so good...
 
J

Jason D.

Jan 1, 1970
0
Yes, ditto to tiny heatsink (either steel or aluminum in other JVC
models. Literally "blistering hot" running.

Cheers, Wizard
 
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