Commodore SX64 probs...

From: Jules Richardson <julesrichardsonuk_at_yahoo.co.uk>
Date: Sat Jul 17 16:15:35 2004

I've got a pair of non-working Commodore SX64's here.

One machine powers up, but the floppy drive light remains lit and I can
hear the drive spinning continuously, and there's a 50% grey pattern
filling the screen (i.e. pixels look to be alternating white/black).
Actually, there's also short run of pixels middle-bottom of the screen
which aren't illuminated at all. Pressing reset has no effect. Pressing
caps-lock does result in the caps-lock light illuminating, but I don't
know if that's a simple circuit hardwired to the key and doesn't go via
the CPU...

The second machine is totally dead - no activity whatsoever. There's a
*very faint* humming noise from the monitor area, typical of a display
that's at least getting power though - but on the CPU side of things no
chips seem to be getting remotely warm, suggesting that there's no +5V.

Before I start digging deeper, does the fault with the first machine
sound familiar, and are there any common PSU faults which affect these
systems? Plus, anyone have schematics they could scan?

Be nice to get one of them going. One keyboard is damaged (plus I only
have the one original keyboard cable), so it's only really viable to
have one running, but I'd like to get to the bottom of what's up with
both of them...

cheers,

Jules
Received on Sat Jul 17 2004 - 16:15:35 BST