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Proscan PSVR80 power supply

Looking for the schematic for just this section if possible. I am
pretty sure I have a flaky supply on one pin. The VCR would work for
a while then display would blank out. Working time got shorter and
shorter.
 
A

AJ

Jan 1, 1970
0
Does the vcr function but just the display craps out? May be specific to the
supplies to the display area. Or is the whole vcr intermittant?
 
Does the vcr function but just the display craps out? May be specific to the

Hi - At this point it's pretty much dead, no display or motor
function. When in it's death throes, I could press a button on the
control panel, it would begin the function (eject, FF, RW etc) the
display would blink out WHILE it was operating, then when the
operation completed, it wouldn't respond to any key presses any more.
If I pulled the plug for a while, then plugged back in and left it
alone, the display would work for a random amount of time before
blinking out.

I took out the power supply section and was probing the pins that fed
everything - I came across a pin that was fluctuating between 6 and 8
volts. I followed the traces on the PCB to a patch of poorly cleaned
flux and thought maybe it was allowing voltage to leak. I cleaned the
flux and tested the pin again - it was hovering steady at 0.2 volts.
I hooked it back into the VCR - still dead. My conclusion is that
there is supposed to be voltage on that pin, but I need schematics to
be sure. I guess eventually I will break down and buy a Sams copy but
at this point the cost is not worth it, so I thought I would through
out the question and see what happens.
 
M

Mark D. Zacharias

Jan 1, 1970
0
Hi - At this point it's pretty much dead, no display or motor
function. When in it's death throes, I could press a button on the
control panel, it would begin the function (eject, FF, RW etc) the
display would blink out WHILE it was operating, then when the
operation completed, it wouldn't respond to any key presses any more.
If I pulled the plug for a while, then plugged back in and left it
alone, the display would work for a random amount of time before
blinking out.

I took out the power supply section and was probing the pins that fed
everything - I came across a pin that was fluctuating between 6 and 8
volts. I followed the traces on the PCB to a patch of poorly cleaned
flux and thought maybe it was allowing voltage to leak. I cleaned the
flux and tested the pin again - it was hovering steady at 0.2 volts.
I hooked it back into the VCR - still dead. My conclusion is that
there is supposed to be voltage on that pin, but I need schematics to
be sure. I guess eventually I will break down and buy a Sams copy but
at this point the cost is not worth it, so I thought I would through
out the question and see what happens.

The most likely culprit, generically speaking, is bad electrolytic caps in
the power supply. Mainly but not limited to the secondary circuit. Anywhere
from 10 to 1000 uF or so, there could be up to about ten of them. They
should be replaced with low impedance 105 degree types - lesser quality ones
may run for a while, then blow the thing up - learned that one the hard way.
Switchmode type supplies are pretty critical about that sort of thing.

Mark Z.
 
The most likely culprit, generically speaking, is bad electrolytic caps in
the power supply. Mainly but not limited to the secondary circuit. Anywhere
from 10 to 1000 uF or so, there could be up to about ten of them. They
should be replaced with low impedance 105 degree types - lesser quality ones
may run for a while, then blow the thing up - learned that one the hard way.
Switchmode type supplies are pretty critical about that sort of thing.

Mark Z.

Thanks for the reply, I'll give that a look. Here's when I wish I had
an ESR tester...

Scott
 
A

AJ

Jan 1, 1970
0
Bob Parker devices are still available at a very reasonable price. Google
for them.
 
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