Date   : Wed, 17 May 2006 23:09:14 +0100
From   : Tom Seddon <tom@...>
Subject: Re: Any ideas?

David Harper wrote:
> M J Forbes wrote: Found this in a box of Beeb bits the other day ... 
> http://www.freewebs.com/mjforbes/romthing.jpg 
> http://www.freewebs.com/mjforbes/romthing2.jpg
> 
> Anyone got any idea what it is?  The lettering on the chip on the
> underside is PC74HCT - D4T if that's any help! It's definitely a 16kb
> SW-RAM bank. I had one exactly like this on my Model B, though I do
> not remember who supplied it. (It may have been Acorn User.)
> 
> The flying lead clips to one of the legs of the CPU. I cannot
> remember which leg, though I do remember it is not the one you would
> expect - i.e. it is not the R/W line. I have a feeling it was a
> memory strobe.

I've got one of these in my beeb. The flying lead connects to the bottom 
right hand pin of IC77 (if you look at the beeb as if you were using it).

--Tom