>> As for the 40-pin chip, unless it's something like a 6500/1 (a micro-
>> controller-like relative of the 6502, as found in the 1520 plotter),
>
>Unless there's some EPROM/ROM in there, it's unlikely to be a
>microprocessor. It might even be a gate array.
There is no ROM that I could see... Also, this chip is completely
unmarked - flat plack plastic DIP with no lettering.
>> > Other apparent power sources from the connector head off into a maze
>> > of op-amps and other analog circuitry, even with schematics it would
>> > take a bit of work to figure out what supplies it was designed for...
>>
>> Hmm... that makes it hard.
>
>Hard, but not impossible. It should be possible to trace the 5 pins of
>that DIN socket. I'll bet one of them is ground (which you must be able
>to find). You mention a regulator. Where does the output of that go
>(+5V line to the lgoic). And does the input come from a pin on the DIN
>socket (that should give you a good guess as to what goes in there). Now
>look at the power pins to the op-amps. Maybe they go straing to the DIN
>socket (in which case I'll go for +/-12V there). Maybe more regulators
>(if so, do the inputs come from the DIN sockets). And so on. I suspect it
>would be possible to come up with a supply that works.
Agreed that it's possible, and when I get the time I will go through it,
I was just explaining why it would be nice to have someone measure the
power supply pins so that I would have a starting place. I can basically
identify all of the pins on the power socket - but I heasitate to
assume +/-12 for the analog - It would be nice to at least have a no-load
measurement... If I can't find any information, it may come down to
doing what you suggest.
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Vintage computing equipment collector.
http://www.parse.com/~ddunfield/museum/index.html
Received on Thu Oct 21 2004 - 06:39:54 BST