17 Jun
2000
17 Jun
'00
6:51 p.m.
"R. D. Davis" <rdd(a)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
17 Jun
17 Jun
10:52 p.m.
Greetings,
Thanks for the help with the 1000E's PSU!
On 17 Jun 2000, Frank McConnell wrote:
[...]
board your power supply is missing is p/n 5061-1349,
the battery
backup board, which is only present in 1000Es with the battery
Good; I won't have to go hunting down a missing board. :-)
backup option. To confirm this, there should be
another board,
[...]
I'll look for this.
Looks like the installer is expected to adjust the
power supply with it
installed in the computer. Test points are on the crossover assembly
Just to be on the safe side, I'll try it out of the computer first if
it will work with no load just to make sure that there aren't any bad
spikes or voltages way too high - using something else to load it if
necessary. If ok, then I'll reinstall the PSU and make any necessary
adjustments.
[voltages, test points, adjustments]
Ok, I'll check those to see which ones aren't working or are out of
spec., if the fans are running, etc.
Feel free to ask questions, I'll keep the manual
out for the next few
days.
Will do. Thanks!
--
R. D. Davis
rdd(a)perqlogic.com
http://www.perqlogic.com/rdd
410-744-4900
18 Jun
18 Jun
1:16 p.m.
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3:34 p.m.
On Sun, 18 Jun 2000, Tony Duell wrote:
I'll try to find a bulb to use. Is it only the 5V supply that has to be
loaded? I've got a resistor that was used for loading a Sun shoebox with
a tape drive and no PSU; I wonder if that would work. I'll have to see
what value it is; about a 10W resistor, IIRC.
Of course, if the PSU has no lose bits in it, and has already been
turned on by someone else before I got it, hasn't any damage that's
going to be done already been done? Hopefully I'll not get LARTed for
asking this, but, how likely am I to do any additional damage at this
point by turning it on attached to the sytem and checking the
voltages?
HP were fond of suggesting that you do this :-(, even
on machines where
the PSU could easily fail in a way that the 5V output went up to a very
high level (like 30V!) I often wondered if it was to sell more CPU boards
;-).
Zog! Why can't they build power supplies with a dummy load built in, or at
least a dummy load and a "test" switch so that the dummy load isn't
attached
to the output when the computer is?
Just to be on
the safe side, I'll try it out of the computer first if
it will work with no load just to make sure that there aren't any bad
Be warned that a lot of HP PSUs of the early 1970's vintage (at least)
don't like being run with no load. I normally load them with a 6V 5W or
6V 21W bulb (depending on the rating of the PSU) before turning them on. Some service manuals warn (in bold printing) against
running the PSU
board with no load (it may even imply that the only load you can use is
the CPU board!). I have never tried to run a PSU like that unloaded, so I
have no idea what would happen, but I can't think it would be a good idea.
Thanks for the warning!
really going on and work out my own set of tests.
Mainly because I then
understand what I am measuring and can make valid deductions if (for
example) I see a very odd voltage or waveform at a particular point.
Makes sense; after all, that's what schematics are for, or, don't
people know how to read them these days? Alas, I don't have a set of
schematics, and will have to settle for whatever info. I can get from
someone who has any troubleshooting information - within reason, of
course.
For much the same reason I've never found
signature analysis to be a
particularly useful technique.
What's signature analysis?
--
R. D. Davis
rdd(a)perqlogic.com
http://www.perqlogic.com/rdd
410-744-4900
4:02 p.m.
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20 Jun
20 Jun
8:55 p.m.
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
rdd(a)perqlogic.com
http://www.perqlogic.com/rdd
410-744-4900
21 Jun
21 Jun
2:02 p.m.
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