Date   : Mon, 22 Jan 2007 14:16:07 -0000 (GMT)
From   : splodge@... (Richard Gellman)
Subject: Narrow Escape...

> Unfortunately I had accidentally connected the
> 5V on the host adapter up to a 12V supply, with
> "hilarious" consequences.

EEP!

I have to concur with other comments, that host adapter is probably little
more than a glorified paperweight now. The entire board is made up of
74-series ICs, which generally pop, melt, smoke, or otherwise die a
cancerous death when connected squarely to a 12V supply.

Fortunately (IIRC) there aren't many capacitors on board (maybe around the
NPGFC debouncer?) and those that were probably protected by the now fried
74xx chips.

On the BBC Micro/Master 128 side, yes the 1Mhz bus is buffered by two ICs,
one for the address bus and one for the data bus. These are either a 74
series bus tranceiver or one of the ubiquitous 81LS95 chips that Acorn was
so fond of. However the bus control lines are largely unbuffered. Since
these are mostly outputs I imagine they have survived.

-- Richard