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

Carlos E Murillo-Sanchez ce.murillosanchez at
Fri Feb 12 11:07:13 CST 2021

Paul Berger via cctalk wrote:
> On 2021-02-11 10:55 p.m., Carlos E Murillo-Sanchez via cctalk wrote:
>> This decade seems to have increased the number of failing things in 
>> such a way that the "to be repaired" backlog is growing much faster 
>> than I can get to diminish it. Argh.  A month ago my trusty 
>> HP9000/380 ran just fine and I booted the different OS's in the SCSI 
>> and HPIB drives connected to it (this particular machine is 
>> interesting because the 9000/300 port of NetBSD was partly developed 
>> in it: it was Mike Wolfson's). Yesterday, it failed to turn 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 supply (at least the output connector; I 
>> can work my way back from that)  and also those for the backplane in 
>> this hp9000/380.  A preliminary search at bitsavers and elsewhere did 
>> not help.  Does anybody have these? 
> I have never seen any schematics for this power supply however on 
> bitsavers there is a document related to the expander that shows the 
> power supply pinout. 
> This would be the same power supply as the processor box. Also 
> Paul.
Thank you!  these will be very helpful.


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