[rescue] HP 9000 712/* power supply?

[Michael Dombrowski]

 I have a picopsu coming tomorrow for the exact purpose of bringing up a 712/60 motherboard. I hope to have time to try it out in the next couple days and I'll report back. 
mike

    On Friday, June 6, 2025 at 03:31:02 PM CDT, Mike Spooner via rescue <rescue at sunhelp.org> wrote:  
 
 Re: 5.1V - it makes all the difference on a different system - the SPARCstation-10. Mind you, the cable harness for *that* is made of aluminium wire, so high-resistance.


On 6 June 2025 18:46:57 BST, Mouse via rescue <rescue at sunhelp.org> wrote:

I presume this is the manual you already found: =
http://ftp.parisc-linux.org/docs/platforms/712_technical_manual.pdf,


I found it on manualslib.com, but, except for manualslib's obnoxious
UI and the line they add to the bottom of each page, it looks the same
(I side-by-side skimmed the first half-dozen pages).


the =
power supply stuff is in 7-1, also a small bit about the =
START_PWR_DOWN_L signal.


I saw that. I may experiment if I can't find anything more definitive.
As long as the board is happy with nothing driving either pin, I should
be OK. If it doesn't work, I'll try pulling the pins to various
voltages with 1K or so resistors....

Not that that's going to happen soon.

Actually, looking at table 7-1 now, I see that it says the main +5 is
actually supposed to be +5.1V, though I am inclined to doubt the
difference matters.

Page 7-2 says that a flashing light on the front panel indicates "a
problem with your graphics subsystem". You've actually got a machine
to look at; can you tell whether that LED is driven by the power
supply, as implied by the PDF's "on the power supply" implies, or by
the board? If the former, there must be some more complex protocol
than just a logic level between board and power supply....


The wire colours described match what I have in my 712/60 (the
motherboard is A2263-66510)


That's reassuring.


pin one/white wire is closest to the SCSI connector.


That matches the pin numbers silkscreened onto the board I have (there
there are numbers 1, 5, and 10 next to those three pins, the same on
each side).

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