HP-1000E PSU

From: R. D. Davis <rdd_at_smart.net>
Date: Tue Jun 20 19:55:17 2000

On 17 Jun 2000, Frank McConnell wrote:
> Looks like the installer is expected to adjust the power supply with it
> installed in the computer. Test points are on the crossover assembly

Well, I've made the initial tests... seems that the problem may be
before the regulators and after the fuse. Since I didn't have a 21W,
6V, lightbulb - I called around to many auto parts stores and couldn't
find one. The few that did have 6V bulbs apparently couldn't be
bothered to open their parts manuals and look for one with a 21W
rating... of course, had I walked in and asked them to check the
books, they probably would have. Anyway, I used one of my other dummy
loads - this one came out of the drivebay of a VAXstation-2000 -
filled with power resistors, which I'm guessing is about the
equivalent load of somewhere between a hard drive and an RX50.

Hooking up the VOM, I got a reading of about 3.5mV for the 5V supply
and between that and zero for everything else. So, it's not completely
dead, but, close to it. And, yes, the fan is spinning.

> (A6) that is visible when you remove the top cover, and the main

Haven't checked that yet.

> adjustment is the +5V ADJ potentiometer that is visible on the power

Does adjusting that make a difference with any of the other voltages?

> 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)

What's the difference between M and I/O in the supply v. column?

> 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.

Something tells me to leave this pot alone at this point.

As I don't have a set of schematics, can anyone tell me what to check next?
Meanwhile, I guess I'll go poking around and see what voltages I can find
in various spots.

R. D. Davis                  
Received on Tue Jun 20 2000 - 19:55:17 BST

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