17 Apr
2013
17 Apr
'13
4:37 p.m.
Symptom: A QX-10 keeps shutting down, but at random and in an erratic way.
By erratic it will sometimes shutdown--Start---Shutdown--start---within a
1/2 second of each sequence.
It sounds like there is a short somewhere or at least some component
failing. But where? Its hard to diagnose because (1) It's intermittent
and (2) I don't want to run the machine when it's flip flopping on and off.
That's definitely not good for the components.
Wehn it does the on-off cycle, what is the power-on lED doing? IIRC
that's conenctesd to the +5V line. If that's blinking o nand off too,
it's most likey to eb a PSU issue. It could be the mainboard drawing to
omuch current, but I think that's a lot less likely.
I've determined that it's either the PSU or mainboard at fault. Both are
for sale on e-Bay. However, I don't whant to buy both when only one is the
problem.
Schematics are avaialble of all the bits of the QX10, including the PSU.
It should be possible to fix it.
Any ideas how I might determine which? The PSU
doesn't not fire at all if
there is no load on it.
Have you tried giving it a dummy load? At least a 6V bulb (about 6W to
12W) betwe nthe 5V output pin and the ground (0V) pin with the PSU
disconencted from the rest of the machine.
-tony