Help Rebuilding an Arcade Machine

[Blove239]

Hey, im new to these forums. I'm currently in a Gr.12 Computer engineering class and we have an old arcade machine that doesnt work and has components from different arcade machines.

It has a monitor from a Sega Model 1, and everything else from I believe a Midway T Unit. The midway board has Mortal Kombat on it.

We have no manuals from the anything and were wondering if it was possible to connect the midway board to the sega monitor. Thanks in advance

[Blove239]

found a serial number for the midway board if that helps

45125 172916

[XYXZYZ]

I'm not sure if that monitor is compatible with JAMMA stuff. (I think it's 24kHz instead of 15kHz)

Read this thread-
http://www.digitpress.com/forum/showthread.php?t=48262

[Blove239]

So we found a pinout for the Mortal kombat board and connected the 5 video cables to the 5 video cables coming out of the monitor. Everything runs fine, except for the picture on the monitor. We see sort of a double image that repeats itself horizontally across the screen. and it sort of overlaps in the middle of the screen. We have tried adjusting the all the potentiometers beneath the screen (horizontal hold, sync etc.) to no avail... im guessing its because of the different refresh rates from the Sega Model 1 to the Mortal Kombat board. Is there any way we can fix this?

Thanks.

[diskoboy]

So we found a pinout for the Mortal kombat board and connected the 5 video cables to the 5 video cables coming out of the monitor. Everything runs fine, except for the picture on the monitor. We see sort of a double image that repeats itself horizontally across the screen. and it sort of overlaps in the middle of the screen. We have tried adjusting the all the potentiometers beneath the screen (horizontal hold, sync etc.) to no avail... im guessing its because of the different refresh rates from the Sega Model 1 to the Mortal Kombat board. Is there any way we can fix this?

Thanks.

Sounds like a sync or resolution issue. Can you post a picture of the symptoms?

I'm guessing it's probably resolution, since most recent Sega games used medium res monitors, and MK used standard res.

Then again, it may just need a cap kit...

[Ken Layton]

We have no manuals from the anything and were wondering if it was possible to connect the midway board to the sega monitor. Thanks in advance

Manuals can be found here:

http://arcarc.xmission.com/

http://www.crazykong.com/

[Blove239]

Thank you very much for those manuals they will come in handy.

I would take pictures of the monitor problem, but now we have a new problem. The board doesnt power up. the speaker makes a repeating, i guess, "buzzing noise" and none of the lights on the power supply or board turn on.

Any suggestions of what to try next?

[Ken Layton]

Measure the DC voltages coming out of power supply.

[Blove239]

I tested the voltage and found there was a problem with one of the power connectors, so now the arcade machine starts up every time. But since we are using a Sega monitor that has a scan rate of 24Khz while the board is 15khz the picture is repeated across it. Is there a converter that can fix this? And we if were to connect the board to a standard VGA computer monitor what do you think the chances of it working would be?

[Ken Layton]

The monitor might be a dual resolution one in which you can select either medium (EGA, 24 khz) resolution or standard (CGA, 15khz) by moving some jumper connectors on the monitor main board. It all depends on the particular make and model of the monitor. Go here and visit the monitor ID sites mentioned:

http://forum.arcadecontrols.com/index.php?topic=62016.0