H7874 power supply

Nigel Johnson nw.johnson at ieee.org
Mon Mar 30 11:52:11 CDT 2020

Vectoring through 24 was very important back in the core memory days 
when the memory would still be there after a power failure and you 
wnated the system to keep running, as was our Ontario Bellboy paging 



On 30/03/2020 12:49, Paul Koning via cctalk wrote:
>> On Mar 30, 2020, at 10:17 AM, Robert Armstrong via cctalk <cctalk at classiccmp.org> wrote:
>>> Looks like for this enclosure an ATX supply could well work.
>>> For my VAX my notes say it didn't.
>>   A VAX would certainly be harder.  You'd have to kludge up the ACOK and DCOK signals for one thing, which I don't think the R400x uses.
> Thise signals don't seem like a problem: just hardwire them to the desired logic level.  PDP-11s need a real functioning DCOK signal iff you want to do power fail interrupt handling, otherwise they don't.  Do VAXen have power fail interrupt?  If yes, does anyone actually use it?
> 	paul

Nigel Johnson

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