Mark D. Zacharias wrote in message
...

"ICESoft" wrote in message
.. .
Been working on this unit off and on for a while. It will power on for
about 1/2 second then power right back off. History on this unit is
that
for a while it started to power off on its own with no rhyme or reason,
it
progressively got worse to the point that it wouldn't power up.
Display
just barely appears before the unit turns back off.

I've checked the output transistors, they tested ok, also checked supply
voltages, they appear good as well. I also resoldered any suspect
solder
joints I could find, still no dice. I don't have a full manual to work
by, just some schematics for it.

Looking for a kick in the right direction...

Thanks,
Benjamin Jennings








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Loop the main (polarized!) power cord back into one of the switched
outlets
at the rear. Run a double - ended polarized cord from the other switched
outlet to your variac or switched power strip. In this way you can bring
up
all the internal voltages without regard to protection status.

A few Yamaha models had problems with the backup cap leaking near the
microprocessor and causing problems like this - but I'm thinking your
model
is NOT one of these. Worth keeping in mind, though. If it comes to
troubleshooting the protection function of the micro I can probably help.
Post back here or you can e-mail me direct at:



and revers the domain name to read sbcglobal.net


Mark Z.



Important safety note:
A mains cable with an unshrouded plug on either end is very dangerous
practise, especially in the UK. If you must have such a cable lying around ,
add some sort of springloaded shroud on one end. eg cable tie around the
cable, to take one end of a spring and a small plastic bottle , cap end
touching the other end of the spring. The bottle large enough to take the
plug but deep enough when retracted to be reasonably enclosed.


ps could anyone explain to me why my newsreader has failed to pick up the
jackhammer posting, no cross-posting AFAICS, checking on Google grouips,
which does have that posting. About once a week it occurs in a thread I'm
following.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/