'not well' Osborne 1 mk 2

From: Witchy <witchy_at_binarydinosaurs.co.uk>
Date: Sun Jan 18 15:09:28 2004

> > They are indeed 4116s, my comment on the glue gun was there
> because 3/4 of
> In which case you can check the +5V, +12V and -5V rails at pins on the
> RAM chips.

All check out fine on multiple random tests, though I have to admit I'm
sitting amongst the smell of singed plastic since it seems the interior of
the machine has been metallised somewhat :-/ It didn't do that yesterday! Oh
well, I'm still with the same problem.....fortunately I saw smoke before
anything nasty happened!

> rails. In other words, you only need to check the voltages at one of the
> RAM chips (assuming there are no cracked tracks on the mainboard, but I
> wouldn't worry abnot that yet!).

OK, so far we have +5V, clock signal and active address and data lines, or
at least my probe makes the expected noises once I found somewhere to get a
good 5V supply from, so I'd say the CPU is running and I have a problem
after that. Normally at this point I'd go for video RAM, but the only
obvious culprits for that are a pair of 6116s that live on the other
daughterboard that supplies the monitor, and I've swapped them round and
swapped in a known good 6116 chip......

The prices of new 'scopes almost made me run to the hills :)


www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(
Received on Sun Jan 18 2004 - 15:09:28 GMT

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