Date   : Fri, 16 Jul 1999 10:11:57 +0100
From   : Mike Tomlinson <mike@...>
Subject: Re: BBC keyswitches

In article <378D7F70.D8E2F6F9@...>, Chris Richardson
<chris@...> writes

>I want to collect together pictures of the different types of keyswitch
>and keytop used on the Acorn 8 bit machines. I am aware of two types for
>the Master 128 

The Master had Issue 1 and Issue 2 switched keyboards.  I cannot
remember the difference between them (changes in the onboard circuit
IIRC), but am sure the keyswitches were the same.  Acorn then issued a
new type of keyboard using a membrane which was pretty hideous.

Working for an Acorn dealer, we found the keyswitches on the Master very
unreliable.  I formed an opinion that they were particularly sensitive
to polluted air.

>and about 5 types for the BBC B. Unfortunately, I have
>not kept records and can only document 2 types for the BBC. 

I can't remember 5 types, only about 3 or 4.  The type consisting of a
square white plunger within a black shell were unreliable; the others
were OK.  Other types were a white switch with an upright prong, a black
switch with an upright prong, and a black switch with an angled prong.

Most keyboard faults on the BBC B were caused by hammering the Return
key during over-enthusiastic games playing, causing the keyboard PCB to
crack.

-- 
Mike Tomlinson