Date   : Sat, 21 May 2005 11:49:53 +0100
From   : "BeebMaster" <beebmaster@...>
Subject: Re: RAM chips for Model B

I think I might have one or two BBC-compatible RAMs I salvaged from an old
Atari or Amstrad PC if
nobody else can help - but I can't test them as none of my Beebs seem to
have socketed RAM.

Best wishes,


Ian

----- Original Message -----
From: Michael Foot
To:  bbc-micro@...
Sent: Sat, 21 May 2005 21:44:33 +1200
Subject: Re: [BBC-Micro] RAM chips for Model B

In message <4d6d8198beinfo@...>
          Sprow <info@...> wrote:

> In article <1116474621.428c0cfdcc78d@...>,
>    Michael Foot <mjfoot@...> wrote:
> 
> [snip]
> 
> > 1) Faulty RAM.
> > 2) Faulty track(s) joining the RAM chips.
> > 3) Faulty 74LS51
> > 4) Faulty 74LS139

I found the problem today. It was indeed a fault RAM chip - IC56 to be exact.
What I did was set
jumper S25 to South and removed one of the socketed RAM chips. I then piggybacked
this chip over
the top of each soldered RAM chip and sure enough the machine booted when
I put it on IC56. So I'm
glad to have found the problem but now I need to find a replacement chip.

Cheers,

Mike.

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