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.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3
Default 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.
  #2   Report Post  
Posted to sci.electronics.repair
AJ AJ is offline
external usenet poster
 
Posts: 107
Default Proscan PSVR80 power supply

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?
wrote in message
...
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.


  #3   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3
Default Proscan PSVR80 power supply

On Dec 15, 9:42 am, "AJ" wrote:
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 wrote in message

...

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.


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.
  #4   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 211
Default Proscan PSVR80 power supply


wrote in message
...
On Dec 15, 9:42 am, "AJ" wrote:
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
wrote in message

...

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.


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.


  #5   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3
Default Proscan PSVR80 power supply

On Dec 16, 5:02 am, "Mark D. Zacharias"
wrote:
wrote in message

...



On Dec 15, 9:42 am, "AJ" wrote:
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
wrote in message


...


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.


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.


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

Scott


  #6   Report Post  
Posted to sci.electronics.repair
AJ AJ is offline
external usenet poster
 
Posts: 107
Default Proscan PSVR80 power supply

Bob Parker devices are still available at a very reasonable price. Google
for them.
wrote in message
...
On Dec 16, 5:02 am, "Mark D. Zacharias"
wrote:
wrote in message

...



On Dec 15, 9:42 am, "AJ" wrote:
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
wrote in message


...


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.


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.


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

Scott


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
HP/Agilent E3632A programmable power supply has power up failure (solution) JW Electronics Repair 0 September 20th 07 12:54 PM
power supply heating problem [2/6] "HIGH POWER 2uS tb.jpg" (1/1) No Name Electronic Schematics 0 April 15th 07 11:13 PM
power supply heating problem [3/6] "HIGH POWER 5uS tb.jpg" (1/1) No Name Electronic Schematics 0 April 15th 07 11:13 PM
ATX power supply to bench supply conversion Kingcosmos Electronics Repair 5 April 4th 07 05:24 PM
X-Box power surge - blew out switching power supply [email protected] Electronics Repair 0 December 25th 04 03:33 PM


All times are GMT +1. The time now is 11:05 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"