Test rig set up

Mindl3ss

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I got my PSone LCD hooked up to my JAMMA tester this weekend but I'm having trouble with the picture. I'm running my Super Street Fighter II X on it and the picture is way too white. All the colors were washed out.

I installed a few trimmer pots on the colors and the image looks better (still a little washed out, but not as much), but if I adjust them the signal starts to degrade and get blurry. I wired them up with one end of the pot on in the wiper on out and the other end grounded.

Any suggestions? Do I need another resistor, or something else? Did I use the wrong size pots (I did use some pretty large ones, but I figured they would at least work on the lower end)
 
Instead of putting pots on the colors, you should be looking to put pots on contrast or brightness. Haven't messed with that LCD screen before, so not sure what adjustments are possible...
 
Have you uncased it? Sometimes there are small pots mounted on the PCB under the housing...
 
Have you uncased it? Sometimes there are small pots mounted on the PCB under the housing...

Yeah, it's completely uncased. As far as I have seen there are no pots on the board at all. I will double check when I get home, but I'm fairly sure there aren't.
 
Looked around the webs, and saw a mention of a contrast and brightness pot on a separate daughtercard, but not sure what it's talking about because there were no pics...
 
wish i could be of help but i postponed the modding of my PSone LCD until i got a proper power adapter (not to mention i still need to order some header pins for the input).

hope you guys figure it out, as i might need this info as well.
 
I installed a few trimmer pots on the colors and the image looks better (still a little washed out, but not as much), but if I adjust them the signal starts to degrade and get blurry. I wired them up with one end of the pot on in the wiper on out and the other end grounded.
What you've made there is a variable voltage divider rather than a variable resistor. You may get a better result if you try disconnecting the ground.

What value are the pots?
 
Looked around the webs, and saw a mention of a contrast and brightness pot on a separate daughtercard, but not sure what it's talking about because there were no pics...

That may be a third party monitor. The Sony LCD has only one daughter board, but it is just for the connections. Everything else is located directly on the controller board.

What you've made there is a variable voltage divider rather than a variable resistor. You may get a better result if you try disconnecting the ground.

What value are the pots?

I did a test without ground and with ground. Before I connected the ground I couldn't really get a clear picture at all. Easy enough to disconnect and try again, I may not have had the pots adjusted correctly the first go.

As for the values, I went with 100K. I figured I could always start them at the bottom and work up from there.
 
Some sites mentioned that the Sony LCD is VGA or composite, not 15k, so not sure if you are using a video adaptor or whether your LCD is different...
 
Some sites mentioned that the Sony LCD is VGA or composite, not 15k, so not sure if you are using a video adaptor or whether your LCD is different...

Yeah, it's definitely not VGA by current standard. It has RGB input and syncs at around 31Hz, where VGA typically does 60Hz. One popular mod involves using these as a secondary computer monitor. Typically people use either the S-Video or software that forces your video card to sync at a lower rate.

JROK mentions tying in some resistors between each color signal and ground. That should fix you up.

See here:

http://www.jrok.com/hardware/lcd/lcd_panel_fun.html

That may be a solution. I was hoping for something that would be adjustable, but I think I can go off of that.

Of course, the LCD they used is third party, it appears to be the right concept.
 
So, after wiring everything back up directly I hooked up buttons I could access through my case and turned the brightness all the way down and now it looks great.
 
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