bytestorm
Armored Scrum Object
- Joined
- Oct 7, 2004
- Posts
- 268
Good evening all!
Got 2 mv6 slots for repair from a friend and have fixed all boards but 1 of the top pcbs..
it had massive corrosion damage and I have patched it extensively, checked all busses for continuity to the connectors.
it will not boot from any slot, and slot 3 wont even show the memory viewer.. and if I check the memory viewer from slot 6 it reads:
0x000100 0x4e45 0x4f2d 0x0a60 0x4f01
the working top pcb gives me:
0x000100 0x4e45 0x4f2d 0x4745 0x4f01
I have been using my logic probe to compare the areas for slot 6 on both boards and the nonworking board seems to have trouble with the signals to/from chip 15 (SDD0-SDD7 according to:
https://wiki.neogeodev.org/index.php?title=SLOT6_board
the working pcb is pulsing nice on all i/o and the non working is just a combination of steady high or low signals.
the 1x 138, 1x 178 controlling the slot selection behaves same on both the non-working and working board, same goes for the 4x 151.
both selects are low on the 244 (chip 15 on wiki).
I am running out of ideas now
I have also cleaned the slots, double checked voltages, resoldered all connector and cart.
Thanks in advance!
Got 2 mv6 slots for repair from a friend and have fixed all boards but 1 of the top pcbs..
it had massive corrosion damage and I have patched it extensively, checked all busses for continuity to the connectors.
it will not boot from any slot, and slot 3 wont even show the memory viewer.. and if I check the memory viewer from slot 6 it reads:
0x000100 0x4e45 0x4f2d 0x0a60 0x4f01
the working top pcb gives me:
0x000100 0x4e45 0x4f2d 0x4745 0x4f01
I have been using my logic probe to compare the areas for slot 6 on both boards and the nonworking board seems to have trouble with the signals to/from chip 15 (SDD0-SDD7 according to:
https://wiki.neogeodev.org/index.php?title=SLOT6_board
the working pcb is pulsing nice on all i/o and the non working is just a combination of steady high or low signals.
the 1x 138, 1x 178 controlling the slot selection behaves same on both the non-working and working board, same goes for the 4x 151.
both selects are low on the 244 (chip 15 on wiki).
I am running out of ideas now
I have also cleaned the slots, double checked voltages, resoldered all connector and cart.
Thanks in advance!