On 01/05/2014 08:22, N_Cook wrote:
On 30/04/2014 23:52, Jon Elson wrote:
Tim Schwartz wrote:

On 4/29/2014 12:33 PM, Apple_Tester wrote:
IBM PS/2 85 server PSU, API manufactured

Diode #ZD1

It's a Zener for sure, since it's labelede ZD1.

Hello all,

I came across this link:

http://john.ccac.rwth-aachen.de:8000/alf/ps2_85/

While it does not give a schematic, it does talk about the power
supply, and from what I see there is no 18V supply. (See the "Details
about main board" section)
Well, it could be a "suicide diode", if the power supply regulation
fails, the diode quickly fails to short and either the PS goes
into overcurrent limit or blows up as it isn't limiting anymore.
Many cheap Chinese PS modules now use these suicide diodes
instead of a more traditional SCR crowbar circuit.

They actually have a special diode made for this purpose.

Jon


Would "suicide diode" be a valid term for searching within a supplier
site?. I've come across guaranteed VTS/diode failure to short and never
open, before , but not able to nail it down. Would you know of any
VTS/diode type number that is definitely made for this purpose?

TVS not VTS. I just tried an assorted set of search terms and yet again
have not found a datasheet for a named TVS, guaranteed (even if only to
some probability) to fail short circuit