NEO-GEO MV-1C White Screen?

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shatterstar78

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Hi, so I just picked up this MV-1C and its having some problems. When I turn it on, all I get is a white screen and no sound. I tried with and without a cartridge. I tested the voltage all around the board, and it looks good. Visually inspected the board, and I could not find anything that looked bad. Theirs no battery leakage or bad caps. I did notice it had a blown fuse that was repaired by the previous owner. The fuse had a piece of wire soldered across it. So I replaced it with a new fuse. I did some searching and found some info mentioning that it could be the 24mhz crystal, so I replaced it but it had no effect. What do you guys think?
 
aha2940

aha2940

AH, A, COLUMBIAN!,
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shatterstar78 said:
Hi, so I just picked up this MV-1C and its having some problems. When I turn it on, all I get is a white screen and no sound. I tried with and without a cartridge. I tested the voltage all around the board, and it looks good. Visually inspected the board, and I could not find anything that looked bad. Theirs no battery leakage or bad caps. I did notice it had a blown fuse that was repaired by the previous owner. The fuse had a piece of wire soldered across it. So I replaced it with a new fuse. I did some searching and found some info mentioning that it could be the 24mhz crystal, so I replaced it but it had no effect. What do you guys think?
Click to expand...

You can use http://smkdan.eludevisibility.org/neo/diag/ to possibly diagnose it.

Regards.
 
bustedstr8

bustedstr8

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I would check it over with a logic probe first, if it doesn't boot the regular bios, I doubt it would boot the diag bios.
They are pretty cheap...$15 or so shipped.
 
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shatterstar78

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bustedstr8 said:
I would check it over with a logic probe first, if it doesn't boot the regular bios, I doubt it would boot the diag bios.
They are pretty cheap...$15 or so shipped.
Click to expand...

True, unless the bios itself if the culprit. I would love to use a logic probe, but unfortunately I have no experience with one. I was looking them up on ebay, any particular one you would suggest? Any tips on using one and what I should be probing, at least when it comes to this board?
 
bustedstr8

bustedstr8

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They are pretty basic devices so any one you pick up should be fine. You want to test the clock circuit, bios, 68K and work ram to start.
The main thing you are looking for is stuck or dead address and data lines on those devices.

The other problem is the bios itself, its a surface mount chip. So any bios swapping would need a Neobiomasta and socket installed on the board.
 
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shatterstar78

n00b
Joined
Nov 10, 2014
Posts
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bustedstr8 said:
They are pretty basic devices so any one you pick up should be fine. You want to test the clock circuit, bios, 68K and work ram to start.
The main thing you are looking for is stuck or dead address and data lines on those devices.

The other problem is the bios itself, its a surface mount chip. So any bios swapping would need a Neobiomasta and socket installed on the board.
Click to expand...

The thing is I never used a logic probe before, how would I now if it should be high or low? I would love to learn how to use one, but im kinda lost.
 
bustedstr8

bustedstr8

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Best way is to just jump in. You can read up on standard logic gates, Boolean algebra, TTL and basic CPU and memory functions. There are some videos sprinkled around, but they aren't very helpful...they just show some basic use. There are a lot of helpful people on NG that can get you pointed in the right direction as well.
 
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