Sanyo Inverted Colors on MAME Setup - help!

apocalypto

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I connected my Sanyo 20EZ to my pc for the first time today to test my MAME setup out and oh noes I have inverted colors!

This is my setup:

VGA Card > 'VGA to CGA Converter Card' > RGB Cable connected to signal input on Sanyo Board.

Here is a picture illustrating the wiring setup:

cablesetup.jpg



Here is a picture of the inverted screen:

inverted.jpg



Is it as simple to fix as finding and installing a Sanyo inverter board? My Sanyo board does not have the separate inverter board mounted to the flyback like some others do. Does anyone have an inverter board they would be willing to sell to me?

FYI, this screen has recently had a full cap kit, including the filter cap.

Thanks guys!
 
Yes, you will need an inverter board AND make sure to get power to it.

OR

To convert the Sanyo monitor to accept normal, positive video:
1. Remove the wire jumpers that have been installed in place of
transistors TR201, TR202, TR203.
2. Remove R213, R214, R215.
3. Install the following components:
a. R201, R202, R203 100K
b. R210, R211, R212 100K
c. R213, R214, R215 820 ohm
d. R217, R218, R219 560 ohm
e. TR201, TR202, TR203 2SC1815 or equiv.
f. C202 220uf 16V
g. D210 1N4004
 
Thanks Kevin. Would the inverter board typically include all cables I would need? How do you power the board?
 
Glancing at your setup you will need one more Sanyo video harness like the one you spliced to go from your VGA/CGA converter to the inverter board.

PC---->VGA to CGA---->Sanyo Inverter---->Monitor Chassis

Power for that those that came equipped with an inverter board originally cam from the monitor chassis itself. It's just one power wire as ground was taken care of through the video harness. (see pic) It calls for 16VDC, but you can get away with running 12VDC to it and it'll work fine. (from like your PC power supply)

I need to redo my regular Inverter Board pic one of these days, but it gives you the general idea of the layout anyways.

The video cable from the VGA/CGA converter would go to the "Video Input from Game PCB".
The video cable from the Inverter board would go from the "Invert Out" to your monitor chassis.
And power to either one of those pins marked 16VDC, they're tied together on the pcb, so they are one and the same.
 

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Thanks for the help Kevin! that really explains it well. I'll see if I can find someone selling an inverter board and another monitor cable.
 
Aside from needing an inverter board I am worried there is another problem with the color.

Please take a look at the following image. The background in windows is totally white. However on the Sanyo it is coming through as a reddish brown color (should be coming in as pure black as it is inverted).

I have tried adjusting the brightness on the flyback and on the screen adjustments board and cannot make it black. I got it close to a gray but it was washed out. I have never touched the color adjustment pots on the neckboard before.

It had a cap kit not long ago and looked excellent with my DK Jr board.
However I didnt do the filter cap at that time. I replaced the filter cap recently and did not test that with the donkey kong board, just this MAME setup. Is it possible the filter cap is bad and causing this color issue?

I really appreciate your help with this!

Thanks

invertedcompare.jpg
 
Filter cap won't cause color issues, it would cause ripples and waves and such.

The color adjustments are probably just a tad off, I would get the inverter board situation squared away before focusing too much on color issues.
 
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