MV1F & MV1FS with graphic issues

A

adrianomartins

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Hi!

I am new on this Forum and that is my first post :)

I have bought 2 boards, a MV1F and a MV1FS.
Unfortunately bouth are faulty :confused:
Here the issues per boards:

MV1F:
Board/game starts but I have some graphic issue (horizontal lines, see pics). I have this error with all games and with original BIOS and with UNIBIOS, i.e. always.

MV1FS:
Board (with and without game, with original BIOS and with UNIBIOS) does start with graphic mess and remains on this Screen (mainly black and White blocks, see pic) with a constant ticking from the speaker.

Do you have an idea where I good start looking for the error, resp. which IC could be damaged?

thanks a lot!
 

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Last edited:
fluxcore

fluxcore

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I've got an MV1F board with similar symptoms to your second board, and am also wondering where to look - there is all kinds of corrosion around the battery area, but I've tried to recreate all the traces (using a working board as an example) and haven't gotten anywhere. I assume one of the chips is malfunctioning.

Possibly something to do with watchdog?
 
Last edited:
A

adrianomartins

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Thanks for the links.
Is there a pinout to check traces between RAM and CPU?
I have found pinouts for ICs around Z80 only.
Thanks!
 
shadowkn55

shadowkn55

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The fix layer is one of the parts of the graphics pipeline.
 
shadowkn55

shadowkn55

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More likely that the fix data lines have issues since both the SFIX and cartridge fix have corruption.
 
A

adrianomartins

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Sorry if I ask again but I am a beginner :-(
What do you mean with "fix data lines have issues"?
That the traces are broken?
I do not see any corruption near SFIX or cartridge fix.
 
shadowkn55

shadowkn55

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adrianomartins said:
Sorry if I ask again but I am a beginner :-(
What do you mean with "fix data lines have issues"?
That the traces are broken?
I do not see any corruption near SFIX or cartridge fix.
Click to expand...

I meant to say corrosion. The fix layer data lines transmit pixel data to the graphics processor. If one or more of the data lines don't have continuity, you'll get graphics problems like in your pictures.
 
Xian Xi

Xian Xi

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If more than one Fix data line is messed up, check the TTL in the top middle of the board. I think it's a 244 or 245, I don't have one on hand so I can't check but all the Fix layer data lines go to it.
 
A

adrianomartins

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you mean the problems on the first two pics right?
not on the third?
how do I know which 2 pins have to be connected between 2 ICs (e.g. TTL and the other ICs)?
 
Xian Xi

Xian Xi

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Well, first you need to check if they have 100% continuity between the TTL and the cart slot. If it's 100% then you check the lines on the TTL. Download the data sheet for it and see which are the inputs and the outputs and compare it to the truth table. You will of course require a logic probe. If the inputs and outputs are working as they should then you know the TTL itself is doing its job.
 
fluxcore

fluxcore

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Thanks for the ideas guys. adrianomartins: I have a working board I can use to get the correct trace routing for those areas, I've already made a spreadsheet with loads of routings, so I'll add to that and hopefully it will help us fix our problems :)
 
Xian Xi

Xian Xi

JammaNationX,
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adrianomartins said:
Thanks. But how do I know which trace goes to what pin of the cart slot? Is it visible from eye?
Click to expand...

I don't have the pinout but easiest way is to get the MVS cart pinout and then use the multimeter continuity check, all 8 lines should be connected to that TTL. FIXD0-D7.
 
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