If you own an early system80 MPU (placed in alle games from Spiderman to James Bond) it might be helpful to replace the 7641 proms, located in socket Prom1 und Prom2 with a single 2716 in socket prom1. Especially, if one of your proms is damaged or the MPU should be used in another system80 or 80A game one day.
B) Modification on the component side of the MPU:
Cut the trace running between pin 6 and pin 7 of Z10.
C) Modification on the solder side of the MPU:
Cut the trace running to pin 19 and pin 21 of the prom1 socket.
Jump a wire between Z10 pin 13 and the pad, that is located under and on the right of Z9 pin 7.
Wire between the following points:
|
socket
prom 1
|
handling
|
socket
prom 2
|
signal
|
|
19
|
connect
to
|
21
|
A10
|
|
21
|
connect
to
|
24
|
VPP
|
|
22
|
connect
to
|
18
|
A9
|
Prom socket 1 is ready to take a 2716 now.
© 2005 Nicole.
