Date   : Sat, 30 Sep 2006 20:16:16 +1200
From   : Michael Foot <mjfoot@...>
Subject: One more BBC B to fix

Hi,

I've got an Issue 4 Model B here which won't start up. The best I can get
 it to work is in 16k mode (jumper 26 south). In this setup, most of the
time when switched on a random configuration will occur. Usually the RGB
output is completely white and the Caps LED comes on then goes off. Usual
ly, but not always, I can press Ctrl-Break after this and different LEDs
will light up and sometimes the RGB output goes black. Also, on only a sm
all number of occassions the machine will boot to a prompt but then lock
up a few seconds later. The keyboard is useable until the lock up.

I've swaped over all the usual socketed ICs, the keyboard and the PSU. I'
ve replaced the 555 timer and IC32 but I still have the symptoms describe
d above.

Can anybody shed any light on what the problem might be? I've not come ac
ross it before and can't tell if it's a bad component or a broken track s
omewhere.

This is 1 of 2 Model Bs out of 20 which I can't get working. Thanks for a
ny help.

Mike.

-- 
Michael Foot <mjfoot(at)paradise(dot)net(dot)nz> *
http://homepages.paradise.net.nz/mjfoot/
* Replace letters between () with @ and . when replying