Date   : Mon, 14 Sep 2009 22:54:58 +0100
From   : philpem@... (Philip Pemberton)
Subject: Mouldy beebs!

Pete Turnbull wrote:
> more careful drying -- labels, some types of relays switches or 
> potentiometers (not a problem on a Beeb, though),

Ah -- that's a point. I forgot about the cassette relay. In all the BBCs 
I've had open, it's been a standard relay with a two-piece snap-together 
plastic casing. I'd be slightly worried about water getting inside it...

As for the rest of the motherboard, I don't have a schematic handy, but 
I seem to recall the Master and B are pretty much devoid of any form of 
potentiometer. The cartridge slots on the Master might be a bit of a 
worry, though, and the speaker (but the latter is removable and there's 
no excuse for putting one in a dishwasher).

 > components in RF cans
> (like the Beeb's modulator).

Should be fine anyway, Astec UM1233 modulators basically consist of a 
PCB, a tin can, a couple of transistors and a few air-core coils. 
They'll dry out if they're put in a warm place for a couple of hours.

I would rather like to see a schematic or datasheet for the UM1233 if 
anyone has one handy. I think I've got about half a dozen of 'em in a 
desk drawer and would rather like to know what makes them "tick"...

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