Date   : Wed, 12 May 2004 12:00:07 +0200
From   : "Eelco Huininga" <e.huininga@...>
Subject: Re: 65c02

Yesterday evening I took another look at the capacitors. The exact value
is 220pF. Perhaps the timing problem with the Solidisk SWR unit could be
fixed by 'playing around a bit' with the value.
I should have the original document somewhere describing this upgrade and
 the timing problem. If I find it, I will scan it and put it somewhere on
line. But as I said: It's somewhere.......... :-)


Cheers,
Eelco



>>> Johan Heuseveldt <johan@...> 05/10 7:53  >>>
Hi Eelco,

> > > > gARetH baBB <hick.bbc@...> 04/27 4:31  >>>
> > > Has anyone come across a reference before about using a 65c02 in
> > > an Issue 7 BBC ?

On Fri 07 May, Eelco Huininga wrote:

> I've upgraded my model B issue 7 and as I recall there were some timing
> problems, pert iculary concerning the video controller. This was overco
me
> by soldering two small capa citors on the mainboard. Yesterday I took a
> look inside the B. I'm using a Rockwell R65C02P2 and have soldered  two
> 47pF ceramic capacitors accross legs 7 and 11 of IC29 and legs 7 and 11
 of
> IC37. I 'm not sure if the 47p value is correct since the stamp has fad
ed
> and is hardly readab le. If anyone needs to know the exact value, I cou
ld
> desolder them and plug them into  my DVM to find out if the 47p value i
s
> correct. Just let me know.

I bought (not received yet) a 65c02 to do this experiment as well, so
your details are much appreciated.

If you can give the exact cap-values, I know what to dug out and solder
into the machine, in case the 6502/65c02 switch doesn't work from start.

> One other problem I've come accross is a timing problem with my Solidis
k
> 32k+96k SWR u pgrade. It seems the 96k has a problem refreshing it's DR
AM
> contents. The 32k board is working perfectly, so I guess Solidisk used
> DRAM's from different manufacturers. I ha ven't come accross a solution
 for
> this problem yet. Maybe one day I'll bring out the g ood 'ol oscillosco
pe
> and try to pinpoint the problem...

I'll have the same and need to do some resolder connections on all
wires, as these are very unreliable. Good to know about the possible
differences between the two banks of RAM.

> Hope this helps some of you guys...

This kind of exact information is always helpfull I reckon! 
Thanks Eelco.


greetings,
Johan

-- 
Johan Heuseveldt <johan@...              >
  aka  waarland

  The best place is a Riscy place
 
One can always be kind to people about whom one cares nothing.