Hello all, I dove into this hobby about 2 months ago and all was going well. I built a basic jamma test rig to test boards out as I buy them. Its basically a control box with jamma harness and power supply built into it and one of these cheap CGA/EGA/YUV/RGB to VGA HD Video Converter Boards built into it to convert the display from the jamma harness to VGA (flatscreen monitor). I put 2 dedicated voltage meters on the power supply so I could see the levels of power coming from the 12v and 5v posts and found a bunch of youtube videos that said to set the dial so you are right at 12v/5v. So all was good I was having no issues playing with the little 60 in 1 boards and pandoras box fired up without issues, etc. Then I got a golden tee 98 board (huge board) and it absolutely would not turn on. after a lot of trial and error I found out that the board would not even boot until I turned up the dial on the power supply to 12.5v/5.23v and even then when it came on the test mode said "low voltage" so I kept slowly stepping it up slowly until it said voltage good. I was a little spooked, but went on with my day. Fast forward a week. Next I found 2 auctions for "Williams high impact football" I bid on them both hoping to win one, I actually won them both... and got 2 boards from 2 different sellers. This time neither of these boards would come up and display anything until I turned the power up too 13.0v/5.75v and when they finally did come on the picture drifts and flips really bad on both boards. And both sellers claimed they were just fine when they tested them. And when I asked what they tested them with I basically got an answer like "just a normal jamma setup"... uh really? thanks... So I suspected maybe the problem is with my test setup? I first suspected my power supply was bad. I have 2 other new power supply's of different brands, I tried them both with the same results. The odd part is I have a few other jamma boards besides the multicades, like tekken 2, dunkmania, etc. All display perfect. So I have a lot of questions that I have no idea who to ask. After going this alone I have come to the humble realization that I need some practical wisdom here. Hoping there is some jamma ninja out there that can give me some basic guidance.
Question 1 - Power - All the service manuals for these games seem to just say the power requirements are 12v/+5v/-5v, yet it appears not all boards work with the same voltages even if their manual says they will. Is it safe to just turn the power supply all the way up just in case or will that damage the boards? How do ops deal with this issue, is every op out there screwing around with the power dial to see what works, or is there a best practice level to set your power supply too? Is there any recommendation for a power supply that works with most boards?
Question 2 - display - Out of all the games I have at the moment I have become obsessed with trying to get High impact football working, mostly because I have 2 different boards that seems act exactly the same, which makes me suspect a problem with my test setup. Im starting to suspect the display drift, flipping, skipping and weird refresh problems to be an issue with the encoder board. I don't have an actual arcade CRT to try plugging in to see if that is better. Anyone out there know anything about this specific game? Power issues or display anomalies? Any recommendations for a display converter board that works good with old jamma boards besides these cheap $20 Jamma Game Monitor to LCD encoder boards? Should I say screw the encoder boards and go buy an arcade CRT? What typically gets the best results?
Question 3 - what hardware should I be using? What do you use to test your boards? (display, power supply, harness brands?)
Question 1 - Power - All the service manuals for these games seem to just say the power requirements are 12v/+5v/-5v, yet it appears not all boards work with the same voltages even if their manual says they will. Is it safe to just turn the power supply all the way up just in case or will that damage the boards? How do ops deal with this issue, is every op out there screwing around with the power dial to see what works, or is there a best practice level to set your power supply too? Is there any recommendation for a power supply that works with most boards?
Question 2 - display - Out of all the games I have at the moment I have become obsessed with trying to get High impact football working, mostly because I have 2 different boards that seems act exactly the same, which makes me suspect a problem with my test setup. Im starting to suspect the display drift, flipping, skipping and weird refresh problems to be an issue with the encoder board. I don't have an actual arcade CRT to try plugging in to see if that is better. Anyone out there know anything about this specific game? Power issues or display anomalies? Any recommendations for a display converter board that works good with old jamma boards besides these cheap $20 Jamma Game Monitor to LCD encoder boards? Should I say screw the encoder boards and go buy an arcade CRT? What typically gets the best results?
Question 3 - what hardware should I be using? What do you use to test your boards? (display, power supply, harness brands?)