Date   : Mon, 14 Sep 2009 22:49:30 +0100
From   : philpem@... (Philip Pemberton)
Subject: Mouldy beebs!

Dominic Beesley wrote:
> Anyway there are some pictures at http://z80homebrew.blogspot.com/

Chuck the parts in a bath, and hit them with nice, hot water (but no 
hotter than 70 Celsius or thereabouts). This works best if you're in a 
fairly soft-water area. Use a toothbrush to get the all the muck off. 
Dry off the bulk of the water, then follow up with isopropyl to drive 
off the remaining water (alternatively put it in the airing cupboard for 
a few hours). High-pressure air (assumption: it's dry air) does a pretty 
good job of driving off water, too.

Don't wash the CMOS batteries (for obvious reasons). If you're dealing 
with Masters that have the "3 AAs on a metal bracket" battery, remove 
the Gaffer tape, pull the batteries and wash the battery holder. Install 
new batteries.

For better results, use a dishwasher on "Intensive" with no soap, salt 
or anything like that. You might have to replace a few capacitors and 
other tall components afterwards, but it'll get the board clean!

Your wife (if any) may have some "choice words" about this, though!

> I?ve picked out the least worst and tried giving it a good dry out and a 
> through washing with Isopropyl alcohol but I just get the beeeeeeeeeeeep 
> of doom!

Does an R-reset do anything?

As far as troubleshooting, I'd start with the power supply (+5V and 
+12V), then check the reset circuitry and clock generation (is the clock 
running? is the CPU being reset on power-up?)

After that I'd probably get the logic analyser, 6502 Inverse Assembler / 
Probing Kit and the Advanced User Guide and see where the MOS was 
hanging (and if the instructions being fetched were valid and in line 
with what should be on the bus at the time).

Yes you can debug with an oscilloscope, but the LA really is a better 
tool...

Cheers,
-- 
Phil.
philpem@...          
http://www.philpem.me.uk/