Did you see the signal shape? Is it decent enough (square angles) or rubbish?
Ok, let's check up banking with unibios.
Use samsho4 and go to ingame menu during neo geo splash screen.
Use patch memory function to bank, write 00/01/02/03 to 2fffff to switch between banks 0/1/2/3. (portwel will go low to latch data)
Manually select a bank via patching then go to memory viewer, and go check address 2ffff0. Hold D to go through faster. It should read 000X (8 times), where X is the bank # you patched in.
Patch in a few bank changes then check the memory value, tell us what's showing up. (not the correct # I guess but meh, let's see exactly)
I like your technique there of using the sam sho cart with a memory patch to invoke a banking switch =D
You aren"t pressing simultaneously.
Hold select + start from unibios splash screen.
Here is a final check list of all I've done:
* Flashed to Unibios and checked the roms, see above pictures
* Cleaned the carts and edge connectors real well (contact cleaner)
* Cleaned the board to board connectors
* Verified voltage @ the harness and PS
* Verified cartridges worked on another Neo Geo.
* Checked internal battery
* Cleared work ram.
I'm waiting on replacement cartridges to test those. In the mean time, does ANYONE have any ideas? thank you.
What a drama you're having.
Sounds stupid but have you opened the carts to check the boards are facing the right way around?
I never insert a new cart into my MVS without cleaning it first anyway. I don't want any dirt etc. going into the cart slot from dirty contacts. Then I do a CRC check via Unibios and will occasionally get errors come up but by removing and reinserting it normally clears this.
If not open the cart again, sometimes a little jiggle straightens up the contacts and away you go. LIttle help I know but eager to see how this resolves itself mate.