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Question on Nortel PSU

T

Terr

n00b
Joined
Oct 29, 2008
Messages
2
I got hold of this big Nortel Passport 8004 DC power supply. On the label it says that it supplies 3.8V at 150A and 12V at 50A.

image1-1.jpg


The input is a standard AC 110 power cord. Output, on the back, though, is a long pin layout, with 3 big pins on one side, then 15 tiny pins, then a lot of medium-sized ones:

Image1.jpg


It is not immediately obvious where the power outputs are, and, of course, there is no manual or anything. So I get a voltmeter and see if I can find things out. I find that the only live pin is one of the 15 tiny ones (bottom row third from right in the pic). The DC voltage between this pin and two of the three big ones is around 9V, same as between it and any of the medium pins. And that's it. No 3.8V anywhere.

Questions:

1. Where is 3.8V?
2. Why 9V and not 12? (I checked the accuracy of the voltmeter with a 9V battery it it showed 9V there too)
3. If I connect just 2 leads - let's say to that 3rd pin and one of the two big pins - will I get 50A or anywhere close to it with load? If I do - will that one thin pin hold?
4. How would I check (3) - should I go get a big resistor, hook it up and measure the voltage across it?
 
A Nortel Passport chassis has a main power switch, so it may be safe to assume that the power supply has a switching method similar to an ATX power supply in that only some of the leads are live until the power supply is "told" to turn on.

I would start in the direction.
 
I understand that for some power supplies, two pins need to be shorted in order to "turn it on" - does anyone have any idea which two pins these might be in this case?
 
Its is usually ground and PS-ON, no idea what the pinout on a Nortel looks like.
 
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