Star Wars Repair Story (long)

Well - I fixed it!, sort of...

I'm posting this in case anyone else has a similar problem.

Description:

The Star Wars game I had would have no stars and the Tie fighters would never
come out. After a while, the graphics would become more and more
screwed up.

The self test indicated "Matrix errors". And dumped out a bunch of hex.

Procedure:

I figured out one of the Mathbox ROMS was bad (#113), by comparing them to
the images on tant.com. I got the correct image and programmed a battery-backed
8kx8 SRAM with the data. Then I rigged a temporary board which mapped the
bottom 4 bits of the first 1K of memory into the socket on the main board and voila
- It's all better now!

(BTW, I struggled for a few days until I realized my bench was wired up with
wire that was too skinny! So, I built a nice thick wire harness for +12 and +5)

Now I simply need a more permanent solution, as they don't make those
signetics PROMS anymore. Maybe this is a common need?

Observations:

I have seen three boards with this failure. Would a small board which plugs into the
mathbox ROM sockets and replaces them with 2764's be useful to anyone else?
It seems like this could extend the life of these boards considerably, because the
Signetics 82S137's run mighty hot and seem to die young, and you can't get them
anymore.

Comments welcome!

Thanks,
Frank Palazzolo

palazzol@tir.com
Received on Sat Jun 21 19:22:51 1997