Info needed on HP 2161A power supply.

From: Bob Shannon <bshannon_at_tiac.net>
Date: Sun Jul 15 09:29:20 2001

Hello list readers..

Does anyone have schematics for a Hewlett Packard 2161A power supply?

This is the power supply for the HP 2115 computers, and I beleive that it was
also used for older HP I/O extenders as well.

I'm having a problem with one of these power supplies, it simply will not turn
on.

All internal fuses have been checked, and a single bad fuse was found.
Replacing
this fuse had no effect and the replacement fuse does not blow.

The back of this power supply has a connector that suggests it may have some
sort
of power-control function (like for I/O expander applications where it is
turned on
by an external signal).

But the 2115 computer simply has 2 massive power cables, and nothing to connect

to this additional smaller connector.

A casual inspection of the 2161A's interior shows no clear power control relay
(this
is a high current linear power supply). Lacking schematics, its not easy to
figure out
what is supposed to be going on inside.

Lastly, when attached to the 2115 computer, applying AC power to the supply
(with all
power switches off) causes the cooling fans in the 2115 to start running. This
seems odd.
I would expect the cooling fans to only start once the power switch was turned
on.

Turning on the power switch has no noticiable effect. I have verified
continiuity from
the power switch (on the 2115) through the cables into the 2161A supply, but I
have not
followed it internally through the 2161A's maze of wiring.
Received on Sun Jul 15 2001 - 09:29:20 BST