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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Mike Scarcella
 
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Default Mitsubishi cs-32509 no power

The set will not turn on now after it died with a loud pop. So far I have
not found the problem after replacing the flyback transformer, HOT,
avalanche diode D961 and the caps on either side of it, and also replaced
the regulator IC951. All diodes in the power supply circuit check ok and
both fuses are ok. I have also resoldered most of the board too.
I have 18v standby when plugged in and when the power on button is pushed I
see voltage on the power on line comming from the opto isolator PC951. The
regulator sounds like it is trying to start and only shows 5v or so on it's
output pin 1, I'm guessing b+ here should be around 130v.
What else can I try on this tv?

thanks for any help, Mike



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Mike Scarcella
 
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Default Mitsubishi cs-32509 no power

I measure 330v at the input to regulator pin 3 and nothing at pin 1 output
when the power on button is pushed. I may have blown the regulator again.
I will try isolating the other voltages from the primary power supply but
they don't seem to be related to the b+ supply in the 32' tv.

"T o d d P a t t i s t" wrote in message
...
I just went through a long Mits CS3535R repair, and have no
idea if the circuits are similar, but on mine, pressing the
power on button fired a relay on a side PC board, which
supplied 120V to a full wave bridge rectifier on the main
deflection board. Pulling the 120V feed connector confirmed
I was getting power to the main board. Then I checked input
voltage to the regulator IC.

Is your input voltage to the switching regulator IC OK?
There were several bad caps in this area that I replaced.

My IC input voltage was getting dragged down by the bad
regulator chip. All this was done with current limiting as
I was in danger of smoking components (again). After
replacing the regulator IC on the primary side, of the main
transformer I was still having problems on the secondary
side where there were four output voltages. Removing the
rectifying diodes one by one for each of the four single
wave rectifying supplies let me track down which PS voltage
supply circuit had problems.


"Mike Scarcella" wrote:

The set will not turn on now after it died with a loud pop. So far I

have
not found the problem after replacing the flyback transformer, HOT,
avalanche diode D961 and the caps on either side of it, and also replaced
the regulator IC951. All diodes in the power supply circuit check ok and
both fuses are ok. I have also resoldered most of the board too.
I have 18v standby when plugged in and when the power on button is pushed

I
see voltage on the power on line comming from the opto isolator PC951.

The
regulator sounds like it is trying to start and only shows 5v or so on

it's
output pin 1, I'm guessing b+ here should be around 130v.
What else can I try on this tv?

thanks for any help, Mike





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