On Nov 6, 9:14 am, "robb" wrote:
i have a micro-controller board with 3 big 40DIP ICs, 10 or so 16
DIP support ICs. with 32v/8v/5v transformer supply that connects
to two bridge rectifiers {32v, 8v}a fuse links sit between
transformer and rectifiers, no schematic.

i believe the 32v shorted with 5V line and it blew one fuse
link. the fuse link was replaced with same and when powered all
three fuses blown.

So....where does one start to diagnose such a *big* problem ?

.
Only thing working is transformer outputs and it seems like i get
continuity hits everywhere i check
the board was built about 1985 (no SMT) it is about 14" x 5" has
3 x 40 DIP ICs and 10 or so 16 DIP support ICs, handful of
transistors many resistors,diodes etc,

ideas and help would be greatly appreciated
robb


First thing you should do is check for shorts across the various power
rails. If a short is found, using a sufficient resolution low-ohms
meter might let you located the offending component. Sometimes the
bypass caps can go short on order gear like this, replace them all if
needed.

Dave.