"Eeyore" wrote in
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robb wrote:

Thanks Tom,
i really appreciate any comments and help

i unsoldered one of the L298 and it has no shorts so now the
next
then i will do a trace of the 5V lines until i can learn
something usefull about the interconnections.

i hate working blind and re-tracing things when i could just
look
on a schemat.

I suggest you remove the 5V voltage regulator.. That'll remove
the connection
from the power supply to the digital section and NOW check for
a short across
the 5V and ground.

The regulator chip may have an internal short you see and it is
at least easy to
remove from the pcb.

Graham



ah ha the L387, i only know this because i looked through the
datasheets i downloaded for all the ICs until i crossed the L387
(5v regulator)

well that just makes too much sense ... start with 5v related ICs
first, i tried to trace the transformer output but had not made
it that far yet

situated next to the L298s (hmm big surprise) i guess i should
have surmised this since all the power regulation for stepper
motors and such is bolted to that heat sink.

i will report results when done, hopefully find some joy

thanks,
robb



that will be next Graham.