[rescue] SGI Challenge L Power

[Sheldon T. Hall]

 Francois Dion writes ...

> As you might remember I had gotten a -12V overvoltage a few weeks back.
> Eventually it resume normal operation and then I powered it off for
> about 2 weeks.

Actually, I have a rancid memory, and I had forgotten.

> You had replied:
> >Great! Of course, the reason for the original error is still unknown....
>
> So something was wrong it seems. How it works right now:
>
> Flick the power to "on", comes on ok, power supply fans are on,
> AC Good led is on (amber). Turn the key to on, and nothing... The
> LED display backlight doesn't even come on. Nor do the two leds
> above the SC come on...
>
> Looking at:
> http://futuretech.mirror.vuurwerk.net/chalonyxdiag/power.html
>
> Ah! It states:
> 2.2.1 System Controller and OLSs
>
> [...]
>
> Each OLS also has a green and amber LED. The amder LED lights to
> indicate that the AC input voltage level is within acceptable
> levels. The green LED lights to indicate that the DC output
> voltage levels are within acceptable levels. Both LEDs should
> remain lit during normal system operation.
>
> And of course, the green LED is off. I wasn't sure if that was
> dependant on the keyswitch or not, but from this it is clear it
> is self-contained. The key only interrupts power from the 48V
> output of the PS to the backplane. So I guess I'll be looking at
> the power supply (Cherokee). Unless somebody has a spare. Man,
> Octane PS are a dime a dozen, but I bet it's going to be hard to
> find a PS for the Challenge.

Are the L power supplies the same as the LX power supplies?  If so, it may
be easier than you think, since folks scrap XLs from time to time.  'Bear"
Stricklin, of this list, may have a real L or Onyx one (I think he has a
couple of Challenge/Onyx chassis).  I've seen 'em on eBay from time to time.
There's an auction for a Challenge MC3 right now, and the chap says he has
"other parts."  Folks who bid on Challenge L parts may, like me, have
collected some spare bits, and one might have a power supply ....

-Shel