I've got a SNES multicart and would like some help to know if it's worth trying to go ahead and fix it.
Here is a picture of the board: A "naked" picture of it: A picture of the back: A small ASCII diagram with the ICs identified:
Code: Select all
+------------------------------------------------------------+
| U6 _ _ U1 _ _ U2 _ _ _____ U3 _ _ U4 _ _ |_
|__ | \/ | | \/ | | \/ | / \ | \/ | | \/ | |
| | | | | | | / \ | | | | |_
+-+ | D1 | |74LS| |74LS| / Epoxy \ |74LS| |74LS| |
| |9625| |139 | | 32 | | Blob | |157 | |174 | |
| | | | | | | \ ROM / | | | | |
++ | | | | | | \ / | | | | |
| |____| |____| |____| \_____/ |____| |____| |
|__________ __________|
| |
|__________________________________________|
Code: Select all
74LS139 74LS32
+--V--+ +--V--+
/CART |1 16| 74'139 (5) |1 14| VCC
BA6 |2 15| /WR |2 13|
74'174 (12) |3 14| 74'174 (9) |3 12|
|4 13| 74'157 (9) |4 11|
74'32 (1) |5 12| 74'174 (2) |5 10|
|6 11| ROM |6 9|
|7 10| GND |7 8|
GND |8 9| +-----+
+-----+
74LS157 74LS174
+--V--+ +--V--+
74'174 (15) |1 16| VCC /RESET |1 16| VCC
BA1 |2 15| GND 74'32(5) |2 15| 74'157 (1)
A15 |3 14| BA2 A0 |3 14| A5
ROM |4 13| BA1 A1 |4 13| A4
BA1 |5 12| ROM ROM |5 12| 74'139 (3)
BA0 |6 11| BA3 A2 |6 11| A3
ROM |7 10| BA2 ROM |7 10| ROM
GND |8 9| 74'32 (4) GND |8 9| 74'32 (3)
+-----+ +-----+
I've tested all the ICs, except the CIC clone, on an old tester and all are fine according to it, except the 74LS157.
I've got some other old 74'157s but all of them tested badly, none worked.
Can someone please explain to me if there's a way to start this multicart with a single fixed game, without using the circuit to change them?
Thanks in advance.
Edit:
Did a "quick and dirty" draw with Eagle.
Hope it helps.