Picked up a cheap copy of Metal Slug which had no sound. Thought it would be an simple case of dry solder on the M1 chip.
Opened the cart up, it's using PROGBK1 and CHA256B (mvs scans and JNX both say CHA256, but mention it might use a later board). The boards are legit, with the correct Toshiba Chips, and sure enough, M1 had a few legs where the soldering looked suspect, too much solder on there and a couple of marks on the board next to those legs.
I sucked the solder off, checked for broken traces (none) and then soldered the legs again, then reflowed each remaining leg. Seeing as it's just 2 V chips, I quickly heated up each leg to let the solder reflow.
Did a quick continuity check to see if the relevant pins were connected to +5v (32) and GND (16) (after looking at datasheet on http://pdf1.alldatasheet.com/datasheet-pdf/view/115079/TOSHIBA/TC531001CP-12.html)
Still no sound. Cart passes check in Unibios if that makes a difference (forgot to check this before, so not sure if it's significant).
I guess the next step is remove the M1 chip, and look trace where each leg actually goes, so I can check continuity on each leg?
Have I missed something? Could the M1 chip be faulty - I don't have a logic pulse tester, just a basic multimeter with continuity tester. (found this thread with a faulty M1 chip - http://www.neo-geo.com/forums/showt...und-on-Last-Blade-2&highlight=sound+solder+m1)
I also don't have another copy of the cart, so can't try mixing the boards up to narrow it down.
Grateful for any advice.
ta
Pete
Opened the cart up, it's using PROGBK1 and CHA256B (mvs scans and JNX both say CHA256, but mention it might use a later board). The boards are legit, with the correct Toshiba Chips, and sure enough, M1 had a few legs where the soldering looked suspect, too much solder on there and a couple of marks on the board next to those legs.
I sucked the solder off, checked for broken traces (none) and then soldered the legs again, then reflowed each remaining leg. Seeing as it's just 2 V chips, I quickly heated up each leg to let the solder reflow.
Did a quick continuity check to see if the relevant pins were connected to +5v (32) and GND (16) (after looking at datasheet on http://pdf1.alldatasheet.com/datasheet-pdf/view/115079/TOSHIBA/TC531001CP-12.html)
Still no sound. Cart passes check in Unibios if that makes a difference (forgot to check this before, so not sure if it's significant).
I guess the next step is remove the M1 chip, and look trace where each leg actually goes, so I can check continuity on each leg?
Have I missed something? Could the M1 chip be faulty - I don't have a logic pulse tester, just a basic multimeter with continuity tester. (found this thread with a faulty M1 chip - http://www.neo-geo.com/forums/showt...und-on-Last-Blade-2&highlight=sound+solder+m1)
I also don't have another copy of the cart, so can't try mixing the boards up to narrow it down.
Grateful for any advice.
ta
Pete