One more thing to fix... HP9000/380 power supply

Christian Corti cc at informatik.uni-stuttgart.de
Fri Feb 12 02:40:54 CST 2021


On Thu, 11 Feb 2021, carlos_murillo at ieee.org wrote:
> to diminish it. Argh.  A month ago my trusty HP9000/380 ran just fine and I 
[...]
> on; the power supply is dead.  So I unracked the pile of drives and the 
> computer, checked for obvious things (the fuse is fine, and nothing in the 
> power supply is swelled up or leaking, or browned by heat; visually, it looks 
> new; the HV caps seem to hold a charge).  I need the schematics for the power

I recently repaired a 9000/310 power supply. The fault was very obvious if 
you are experienced with the components used. My machine was built in 
Germany (Böblingen) and has a German power supply that uses electrolytics 
from Frako (the golden caps). They tend to simply short from one moment to 
another. In this case one of them shorted the +12V rail and thus the power 
supply shut down. No other blown parts or fuses. Just find the shorted cap 
and replace it :-)

Christian


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