"Joerg" wrote in message
t...
legg wrote:
On Tue, 6 Nov 2007 07:25:01 -0500, "robb"
wrote:

this is the board where the 32 V line shorted with 5V line
at the
green ribbon connector near transformer and only blew center
busman fuse . i get continuity between 5v and 0V ref and now
i
need some advice where to start looking for problems or some
methodology on what to do (pull ICs, etc)

and of course no schematic, i am trying to map the power
section
now


Pull connectors. Repeat 5-0V z test at both ends.

On the end with zero ohms:
- Is there anything that looks like a zener or crowbar across
the 5V
rail? Not likely, but check anyways. Disconnect them and
repeat z
test.

- Identify the 5V regulator, if present. Remove and repeat z
test.

- Apply 5V current-limited to 100-1000mA. Check mV appearing
on 5V
tracking, looking for lowest values and finger components (
IC and
caps ) for temperature rise.

Yep, that's how it's done. If you have access to an infrared
imager or
camera that can greatly speed up the search.

There is always hope ;-)

Thans Joerg,

The only thermal imager i had was a cheapie and inaccurate
**finger** but i had 8 of those in case any lost sensitivity and
two backup *thumbs* in case the fingers blew a sensor

forgot to thanks you earlier , thnaks for help,
robb