Ok both of these are my parents and they had a brown out. Both then
refused to work and when taken apart the fuses were blown. After the
second replacement fuse blew I knew something else was wrong. I could
really use the schematics if anyone has them. I can't seem to find
them.

Aside from that I have figured out that the power supplies are
Swithing Mode Power Supplies. Both the boards are virtually identical
in power layout. I did some searching and found out that for these
power supplies when they won't power on and keep blowing fuses you
should test the main transister on there. I pulled them both off to
test them properly and they both game me different readings but I
think they are both shot based on the readings I got. I managed to
find replacements at MCM electronics and ordered them. Any ideas or
help would be appreciated. If this doesn't work should I check the
bridge rectifiers? How do you test those?

Thanks!

"Brendan" wrote in message
om...
Ok both of these are my parents and they had a brown out. Both then
refused to work and when taken apart the fuses were blown. After the
second replacement fuse blew I knew something else was wrong. I could
really use the schematics if anyone has them. I can't seem to find
them.

Aside from that I have figured out that the power supplies are
Swithing Mode Power Supplies. Both the boards are virtually identical
in power layout. I did some searching and found out that for these
power supplies when they won't power on and keep blowing fuses you
should test the main transister on there. I pulled them both off to
test them properly and they both game me different readings but I
think they are both shot based on the readings I got. I managed to
find replacements at MCM electronics and ordered them. Any ideas or
help would be appreciated. If this doesn't work should I check the
bridge rectifiers? How do you test those?

Thanks!

With respect, vcr and tv/vcr switchmode supplies are no place for newbies.
Besides, at this point, even if the switcher transistors are bad, there's
likely other parts bad a well. I strongly recommend professional service or
replacement. If you throw them away cut the cords off first.

Mark Z.

Sounds like you may be a bit in over your head, it may be best to have a
service estimate done.
"Brendan" wrote in message
om...
Ok both of these are my parents and they had a brown out. Both then
refused to work and when taken apart the fuses were blown. After the
second replacement fuse blew I knew something else was wrong. I could
really use the schematics if anyone has them. I can't seem to find
them.

Aside from that I have figured out that the power supplies are
Swithing Mode Power Supplies. Both the boards are virtually identical
in power layout. I did some searching and found out that for these
power supplies when they won't power on and keep blowing fuses you
should test the main transister on there. I pulled them both off to
test them properly and they both game me different readings but I
think they are both shot based on the readings I got. I managed to
find replacements at MCM electronics and ordered them. Any ideas or
help would be appreciated. If this doesn't work should I check the
bridge rectifiers? How do you test those?

Thanks!

See the SMPS Repair FAQ at the site below. You are correct about the
switchmode transistors being blown but it's possible they took out some
other parts which will cause the new ones to blow immediately. If the
VCRs are more than say 10 years old, the electrolytical capacitors in the
power supplies may also need replacing.

There are also power supply rebuild kits available for a modest cost.
This may be the best route as they will have all the parts that are
likely to be bad.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the Feedback Form in the FAQs.


"Art" writes:

Sounds like you may be a bit in over your head, it may be best to have a
service estimate done.
"Brendan" wrote in message
om...
Ok both of these are my parents and they had a brown out. Both then
refused to work and when taken apart the fuses were blown. After the
second replacement fuse blew I knew something else was wrong. I could
really use the schematics if anyone has them. I can't seem to find
them.

Aside from that I have figured out that the power supplies are
Swithing Mode Power Supplies. Both the boards are virtually identical
in power layout. I did some searching and found out that for these
power supplies when they won't power on and keep blowing fuses you
should test the main transister on there. I pulled them both off to
test them properly and they both game me different readings but I
think they are both shot based on the readings I got. I managed to
find replacements at MCM electronics and ordered them. Any ideas or
help would be appreciated. If this doesn't work should I check the
bridge rectifiers? How do you test those?