18 Jan
2003
18 Jan
'03
4:32 a.m.
On Jan 18, 12:49, Adrian Vickers wrote:
At 06:41 18/01/2003, Ethan Dicks wrote:
I bring it up because I _think_ you are talking
about the original
chicklet-keyboard SRAM PET, but you didn't come right out and say so.
Apologies, I didn't; I keep forgetting that the 2001 went through more
development than perhaps any of the other PETs. Yes, it is a chicklet
keyboard version, with static RAM (2114's) and original 28-pin MOS ROMs. Well, there are no unpolulated sockets, so perhaps
it's a fair bet that
there's some extra stuff in there. Goodness knows what, though, all the
ROMs are MOS 6540's.
Then there's no extras. The MOS Technology 6540 ROMs are half the capacity
of the 2332s in later boards, so there are seven of them in a standard PET
and no spare sockets.
Figures :( I've had to do this once already to
locate a broken 2114
(when
I got the machine, it claimed only 1600 bytes of
memory were free).
Luckily, I have one more spare 2114 (I got two from someone on this list,
I
forget who [for which I apologise] and thank them
(again) profusely, as
if
it is a broken 2114, there's a chance the second
spare might be
essential).
I think it was me (and I think you already said thankyou :-))
Also, I know this has been asked & answered
before, but what's the best
way
of cleaning the board? It has more dust on it than I
am properly
comfortable with, and besides it looks horrible.
I'm guessing that *ideally* it should be washed in distilled water with a
very soft brush, then left in a warm place to dry thoroughly. OTOH, maybe
alcohol would be a better idea? I have some disc head cleaning alcohol
which would suffice - recommendations please!
Start by vacuuming it with a powerful vacuum and a soft, small, paintbrush
(about 1/2" - 1") to help disldge the dirt. You might not need to wash it
after that. It's not too important for a board like this, but the air
rushing through a plastic vacuum nozzle can generate a surprising amount of
static, so ideally the nozzle should be conductive, and grounded.
If you do wash it, use some detergent, do not get it too hot, rinse with
distilled water and a *very small* amount of wetting agent (to help the
water drain). Blowing off the excess with low-pressure compressed air
and/or rinsing in IPA or meths (which mix with water and helps remove it)
may also be a good idea. Do make sure you get all the water out of places
like IC sockets, switches, and connectors, as residues may eventually lead
to corrosion.
In extreme cases, or where I've had a lot of boards to clean, I've used the
dishwasher -- but do not let the dishwasher do the normal drying cycle as
it's too hot for safety. Some dishwashers seem to use very hot water, too,
and some types of PCB and some types of plastic don't like that. Don't use
a dishwasher on boards that have non-sealed relays, transformers, paper
labels, etc.
--
Pete Peter Turnbull
Network Manager
University of York