Date   : Sun, 01 Oct 2006 21:07:05
From   : Michael Foot <mjfoot@...>
Subject: Re: One more BBC B to fix

Hi,

In message <$c58DJAT2qHFFwxe@...>
          Mike Tomlinson <mike@...> wrote:

> In article <6ef7606e4e%mjfoot@...>, Michael Foot
> <mjfoot@...> writes
>
> >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. Usually, 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 small number of occassions
> >the machine will boot to a prompt but then lock up a few seconds later.
>
> Have you swapped out the VIDPROC and ic14 (74LS245)?  If the VIDPROC is
> the Ferranti one, does it have the heatsink?

Yes I have since they are both socketed. The current VIDPROC is a VTI one so I
assume in the past the original VIDPROC was replaced with the current one.

Do you think the fault is caused by a video circuit problem? Do you think it's
more likely to be IC related, connection related or some other component?

Thanks,

Mike.

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