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.


You are losing the patient.


There is always hope ;-)

--
Regards, Joerg

http://www.analogconsultants.com/