Hey Guys,
After 5 or so years, a house move, family and whatnot, I'm finally back into Neo Geo-ing :-)
I've successfully brought a dead and rusty MV1C back to life and got bitten by the fix it bug!
I really want to extend my learning with electronics and what better way to do that, than repairing my favourite gaming system...Neo Geo :-D
Soooo, last week I purchased an MV1FZ from a dude who said it worked, but with known graphics glitches.
The board arrived last week, along with an MV1A (that's a thread for another time) and I immediately threw it on the test rig to see how it functioned.
EVERYTHING works great, apart from the graphics problem you can see in the pics below.
I've done my research...I think. My problems almost looks exactly like the example found here:
https://wiki.neogeodev.org/index.php?title=Graphic_glitches
Something to do with the Lower Address Lines on the C Rom. I think my issue reflects what is written about Address A3, as my mirrored graphics lines look similar to the examples on the neogeodev website.
Previous owner marked the LSPC2 and NEO-B1 chips as possible faults. I really hope not as I don't have a donor board with these chips to do a replacement.
I'm thinking there is something way simpler at fault, and that's where I'm hoping I can get suggestions from the community.
What I have done so far.
- After my initial test of the board, removed the original Bios and replaced it my my licensed UniBios 4.0...no change in graphics state.
- Bough a TL866II Plus Programmer and made myself an SMKDAN Diagnostics Bios. Was a fun excise as it's not something I've ever done before, No faults found, ALL TESTS PASSED!
- Bought a USB Microscrope and looked over every square centimetre of the board, very diligently, to try and find broken traces, weak solder points and such...Found nothing!
- Looked over all through-hole solder pins on connectors, sockets and caps to make sure there were no shorts...Found nothing!
- Went over ALL traces with a multimeter in continuity mode to make sure all the Connections between the vertical Cart Slot and main board were OK...Everything checks out OK!
- Made sure it wasn't the game I was using to test boards...All good, game works flawlessly in the other 4 MVS Systems that I have here.
- Bought a Logic Probe and started poking around chips to see what noises I could make. Was fun, but as I really don't know what I'm looking for, and where I should be looking, wasn't really beneficial :-D
The board looks almost factory new I think. There was very little in the way of dirt, exorbitant amounts of flux residue...nothing really.
The only thing removed from the board was the battery...and it was a clean removal.
Nothing else on the board looks as though it's been tampered with.
There are NO signs of corrosion what so ever.
All Caps look original, in good order, no leaking, no puffing, all look really good.
While I can understand the appeal of continuing to use the system as is (it does make gaming on it more challenging), I'd really like to get it back to an original working state.
Or is this an issue that will likely see no resolution, therefore I've got a nice parts board?
Thoughts anyone, where can I begin?
Cheers,
Batesey
After 5 or so years, a house move, family and whatnot, I'm finally back into Neo Geo-ing :-)
I've successfully brought a dead and rusty MV1C back to life and got bitten by the fix it bug!
I really want to extend my learning with electronics and what better way to do that, than repairing my favourite gaming system...Neo Geo :-D
Soooo, last week I purchased an MV1FZ from a dude who said it worked, but with known graphics glitches.
The board arrived last week, along with an MV1A (that's a thread for another time) and I immediately threw it on the test rig to see how it functioned.
EVERYTHING works great, apart from the graphics problem you can see in the pics below.
I've done my research...I think. My problems almost looks exactly like the example found here:
https://wiki.neogeodev.org/index.php?title=Graphic_glitches
Something to do with the Lower Address Lines on the C Rom. I think my issue reflects what is written about Address A3, as my mirrored graphics lines look similar to the examples on the neogeodev website.
Previous owner marked the LSPC2 and NEO-B1 chips as possible faults. I really hope not as I don't have a donor board with these chips to do a replacement.
I'm thinking there is something way simpler at fault, and that's where I'm hoping I can get suggestions from the community.
What I have done so far.
- After my initial test of the board, removed the original Bios and replaced it my my licensed UniBios 4.0...no change in graphics state.
- Bough a TL866II Plus Programmer and made myself an SMKDAN Diagnostics Bios. Was a fun excise as it's not something I've ever done before, No faults found, ALL TESTS PASSED!
- Bought a USB Microscrope and looked over every square centimetre of the board, very diligently, to try and find broken traces, weak solder points and such...Found nothing!
- Looked over all through-hole solder pins on connectors, sockets and caps to make sure there were no shorts...Found nothing!
- Went over ALL traces with a multimeter in continuity mode to make sure all the Connections between the vertical Cart Slot and main board were OK...Everything checks out OK!
- Made sure it wasn't the game I was using to test boards...All good, game works flawlessly in the other 4 MVS Systems that I have here.
- Bought a Logic Probe and started poking around chips to see what noises I could make. Was fun, but as I really don't know what I'm looking for, and where I should be looking, wasn't really beneficial :-D
The board looks almost factory new I think. There was very little in the way of dirt, exorbitant amounts of flux residue...nothing really.
The only thing removed from the board was the battery...and it was a clean removal.
Nothing else on the board looks as though it's been tampered with.
There are NO signs of corrosion what so ever.
All Caps look original, in good order, no leaking, no puffing, all look really good.
While I can understand the appeal of continuing to use the system as is (it does make gaming on it more challenging), I'd really like to get it back to an original working state.
Or is this an issue that will likely see no resolution, therefore I've got a nice parts board?
Thoughts anyone, where can I begin?
Cheers,
Batesey
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