HP-1000E PSU

From: Frank McConnell <fmc_at_reanimators.org>
Date: Sat Jun 17 17:51:02 2000

"R. D. Davis" <rdd_at_smart.net> wrote:
> One slight problem: I'm told that the PSU is bad. Upon removing the
> cover from the PSU, I noticed that there are three plug-in boards in
> the PSU, and one empty PCB connector, the second one back from the
> front. Is this circuit board supposed to be missing? I've not teted
> the PSU yet, as I didn't know if doing so with this (optional? a
> regulator for a voltage this system doesn't need?) board removed will
> damage it. Is it safe to power it up with this board missing?

Very likely. I pulled the 1000E Installation and Service Manual
(HP p/n 02109-90015, dated Nov 1979) and it would appear that the
board your power supply is missing is p/n 5061-1349, the battery
backup board, which is only present in 1000Es with the battery
backup option. To confirm this, there should be another board,
5061-1351, in another slot in the power supply -- this is a jumper
board that is used in place of 5061-1348, the battery charger board,
when the battery backup option is not present. I think you'll find
this latter board in the slot closer to the front.

Looks like the installer is expected to adjust the power supply with it
installed in the computer. Test points are on the crossover assembly
(A6) that is visible when you remove the top cover, and the main
adjustment is the +5V ADJ potentiometer that is visible on the power
supply board that is partially exposed when you lower the front cover:
it's the one that is under the LOCK/OPERATE switch.

Supply voltages are:

supply v max cur upper lim lower lim test point
+5V I/O 50A 5.25Vdc 5.00Vdc A6 +5V
+5V M 4.5A 5.25Vdc 5.00Vdc A6 +5M
+12V I/O 2.5A 12.6Vdc 11.4Vdc A6 +12V
+12V M 2.0A 12.6Vdc 11.4Vdc A6 +12 M
-2V I/O 4.0A -2.2Vdc -1.8Vdc A6 -2V
-12V I/O 2.0A -12.6Vdc -11.4Vdc n/a
-12V M 250mA -16Vdc -9Vdc A6 -12M
                       (unregulated)
+30V I/O 250mA 42Vdc 22Vdc A6 J2 pin 4
                       (unregulated)

The general thing to do at initial checkout is to adjust the +5V ADJ
pot 'til the first of these is at +5.15 +/-0.05 volts, then check the
other voltages to make sure they're within range.

OK, so what about troubleshooting? There's a flowchart, which I'm not
going to try to turn into ASCII, but here's the first question after
you turn the machine on: are fans running? Beyond that...well, this
flowchart looks like it's intended to help you troubleshoot to board
level and in some cases transistor level. So supposing the fans are
running, the next questions are whether +5V is present at the
crossover board test point, and whether it is adjustable as described
above.

Feel free to ask questions, I'll keep the manual out for the next few
days.

-Frank McConnell
Received on Sat Jun 17 2000 - 17:51:02 BST