Date   : Wed, 15 Jul 2009 13:43:44 -0500
From   : jules.richardson99@... (Jules Richardson)
Subject: happy bunny

Rob wrote:
> So.. Question ... what's the safest way of checking these over and
> powering them up?

I take 'em to bits[1] - it's amazing the amount of staples, paperclips and 
other conductive crap I've seen work their way into old systems whilst in 
storage. The really fun ones are where the debris gets *under* a PCB and 
shorts things out :-)

I check PSUs over with a dummy load - having a bad one that goes over-voltage 
is rare, but I've seen it happen (usually if faulty they under-read or are 
outright dead).

Other than that I'll just give the boards a once-over to check for any obvious 
problems (loose wires, chips falling out of sockets, heatsinks fallen off etc. 
etc.). I quite often find that chips will need re-seating, but I don't bother 
doing that until I know there's a fault; I don't remember ever outright 
breaking something just because IC contacts were bad.

[1] which is also a good time to get all the dust off the PCB and wash the 
casing while there's no electronics inside!

> I'm just a bit wary of letting all the
> magic smoke out of the capacitors, given these have not been used for
> so long.

I've seen a *lot* of machines smoke. I've never had it cause any damage to 
anything else though; worst-case it just seems to make a mess that needs to be 
cleaned up (and of course the part needs replacing). I've found that those X2 
caps often go after the machine's been running a few hours, not immediately, 
so there's no easy way of telling if one's bad until it actually fails 
(leaving the machine running for a while is a useful test anyway - I've seen 
machines where the video dies only after a while, or memory faults start 
cropping up after a hour or two etc.)

> And the filestores, of course!

The contents might be worth preserving as a 'snapshot' of what schools were 
using machines for in the 80s.

IDE and SCSI hard disks I'll back up straight away on modern kit - ST506/412's 
are a bit more tricky and I've found best done via the original equipment.

Overall, just be methodical about it all - give everything a good once-over, 
clean, fix obvious faults, test whatever you can in isolation. It's depressing 
how much stuff we used to get offered at the museum where the owner "just 
turned it on to see if it still works" and broke something!

cheers

Jules