"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
Many of the Yammies use some 4 pin regulator ICs. They are common failures.
Usually the +5v ones, type PQ05RD11, and their output will drop typically to
about 2v or so. When they go faulty, they tend to give just the symptoms
that you describe. There are usually type PQ3RD13 around too. These are
+3.3v. I'm not certain if that model uses them, but have a look in your
schematics, and if yes, have a careful check on their outputs with your DVM.
Arfa