[SunRescue] exploding sun psus

[kebabthesheep]

Well, it cetainly has been an interesting weekend.  Massie and I 
bimbled on over to chez
Honniball, and cleaned him of house and home :)  The sun 3/470 and 
4/370 *just* went in the car,
and the boot filled with sparcs.  Muchos gracious!

Build up the 3/470, dropped in my spare scsi controller, and off we 
went.  Booted sunos4.1.1.sun3x
just fine, but I got bored and didn't install it.  For some reason or 
other I put a card in the
slot next to the psu, so in order to get it out again - to diagnose the 
vme interrupt errors - I
had to pull the psu.  So all cards except cpu, memory and scsi out, psu 
back in.  All checked for
seating, and screwed down.  Power up.  **BANG**  Psu blows its guts out 
:(

Now I've never experienced a big psu blowing, and I don't want to again 
- 1300W of psu makes a big
mess :(  It looks as if a capacitor failed, and took out some 
semiconductors.  Much ceramic
shrapnel now being distributed throughout :-/

I took the whole machine apart, and checked all electronics over with a 
magnifying glass.  I
couldn't find a burnt connector, overheated track or any visible form 
of damage.  SO I just
reassembled with the psu out of the 4/370.  Works now :)

Capacitors are starting to become my least favourite electronic 
component (what after realising
i've over 7 sun slc/elcs to repair due to cap failure) 

Ah well.  The backplane on the 3/470 is a bit wierd tho - neither scsi 
controller works today -
which is odd.  Yet both function in my 3/140, even the one John said 
was broken!

Anybody got any docs on the 3/4xx backplane configuration?  Anybody got 
a spare?  Anybody seen one
with some solder on it - with components attatched by more than a press 
fit into the plated-holes?

I'm confused :-?  

OH - the RML380Z now works fine with it's replacement low-density 
controller :)  Both drives light
up, make noise and try to do things, so I'm a happy bunny :)  I'd still 
like to get the high
density controller going sometime - but a least now i'm one step closer 
to booting cp/m.

Dave.


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