Vintage Synth Repair

--- In vintagesynthrepair@yahoogroups.com, "GB" <grantbt@...> wrote:
>
> You might want to test to the continuity between the CPU and the 
memory
> chips for all the data/address/control lines and at the same time 
make sure
> there are no shorts to other data/address/control lines.

Hmm, good thought. There are some pull-up resistors in a SIL
package that got a fairly good covering of battery gunk. I'll
do some more prodding before condemning the CPU.

> Is it in a socket?  If it's not, put it in one (well, the 
replacement IC).

No, unfortunately. All chips except the EPROM are soldered in.

> What's the whole part number on it?  Do you have schematics? I'd
> like to see them.  You might be able to find one on ebay, although
> you might also have to buy something that has one on/in it.

I'm afraid the full part number has rubbed off with the cleaning
up operation. Schematics I downloaded from here:

http://www.oldcrows.net/~patchell/poly800/poly800.html

but the quality is very poor. If I can establish that it's worth
spending the money on, then I'll get a proper manual from
wdgreenhill.com, but these synths are 10-a-penny on ebay so I'm
not going to go overboard on it. It is a rarer reverse-keys model
though, so I may see if I can find a bargain normal one to use
as a parts donor.

> You might be able to find one on ebay, although
> you might also have to buy something that has one on/in it.

According to:

http://www.solarviews.com/eng/rover.htm

it was used in the Mars Sojourner rover, but shipping costs might
be a bit excessive :-)

Cheers

mark-r