H7874 power supply

[Paul Koning]

> On Mar 29, 2020, at 2:14 PM, Robert Armstrong via cctech <cctech at classiccmp.org> wrote:
> 
>> Maciej W. Rozycki <macro at linux-mips.org> wrote:
>> numerous Chemi-Con SXF parts scattered across 
>> all boards, some leaking
> 
>  Yeah, mine is full of "Nippon Chemi-Con" electrolytic too.  
> 
>  What about just gutting the PS chassis and sticking in an ATX power supply?  I don't know how the maximum current per output breaks down, but as I understand it the H7874 is only a 600W supply.  That's not a problem for an ATX supply, and it would have all the required output voltages.  You'd have to run the cabinet fans at a fixed speed and you'd lose the power control bus feature, but that's not a show stopper.
> 
>  Actually my unit is in an R400x chassis full of RF drives, so I believe I only need +12 and +5.  I don't think the 3.3v and -12 are used in that case.  I wonder how much current I really need for the drives?  I should look that up and I might be able to find a surplus dual output supply that would do the job.

I had a similar thought for a PRO supply that blew its input filter (of all things).  It does +5, +12, and -12.  The -12 is needed at least for RS232.

	paul