Date   : Mon, 08 May 2006 21:46:40 +0100
From   : Sprow <info@...>
Subject: Re: More fun with DFS, TUBE, yada yada

In article <7.0.1.0.2.20060508205632.03620ea0@...>,
   Joel Rowbottom <joel@...> wrote:
> Right, i've got a bit further and worked out I had three (!) busted 
> 7438s in my junkpile. Now I have 1770 DFS working.

Sigh.

> I picked up some time back a 6502 2nd processor and a Z80 2nd 
> processor. The 6502 one doesn't have the PSU with it but I've tested 
> it running from one of the +5 rails in the Beeb although I suspect 
> this isn't recommended :P Question is, is it advisable to run the 
> 6502 2nd processor from the internal BBC B power supply for any 
> length of time? If so I might as well just wire up something from the 
> external power port to run it.

You could measure the current, and compare it with a beeb powered floppy
drive, then base your decision on that: no floppy, but perhaps a coprocessor.

You should also note that the +5V is on the Tube connector already, so self
powering the board should be just a matter of making the appropriate link.

> The Z80 2nd processor just causes mad screen issues. I don't think it 
> works.

Try swapping the ULA with the one from the 6502. I have spares.
  http://www.sprow.co.uk/bbc/forsale.htm

> Now, the other question. Over the years I've acquired a few bits and 
> bobs of Beebs as we all have, and found that I have two Acorn speech 
> upgrade chipsets. One of them works fine with the chip ID TMS6100NLL. 
> The other one is slightly different and appears to either be a blank 
> PHROM or doesn't have any usable data in it - the chip is VM61002NL - 
> anyone got any clues? (pics of the non-working chipset at 
> http://photos.jml.net/p28992450.html).

It might be a non UK PHROM.
Try SOUND-2,word,0,0
and SOUND-3,word,0,0 etc
up to -15.

Alternatively, my speech chips are available individually too.
  http://www.sprow.co.uk/bbc/speechupgrade.htm
Sprow.