Pana Twin Supergun - Video outputting via S-Video but not RGB

Digmac

Official NG Youngun
I know this issue has so many variables, but I need some ideas in what could be the issue.

I got in my Pana Twin MP-92 supergun. Everything works perfectly with normal arcade boards. I've been using it every day without issues. I wanted to use the Mahjong panel on the supergun, so I wired up a Mahjong board harness. I checked continuity multiple times and my harness checks out. It's wired 100% correctly for Mahjong boards and the Pana fingerboard pinout. I got in a Taisen Hot Gimmick PCB, hooked everything up, and get no picture. I get sound, controls work, but no picture via RGB out. The supergun has an S-Video out, so I plugged that into my PVM and that gave me video, showing the board is fully working. I swapped back to RGB via SCART to BNC, and again, no video.

I double checked my voltages on +5v and +12v, they're sitting at 5.08v and 11.92v. I'm getting 3.77v on the sync line from the PCB. Again, the pinout has been continuity checked multiple times. The supergun has multiple video adjustments, including a sync adjustment. I've tried them all and nothing effects the issue.

Any ideas guys?

Thanks.
 

Neodogg

Dogg-Father,
did the RGB work before this board/ with other boards?

I had a similar issue and had to make a custom scart cable for my Sega Boardmaster
 

Digmac

Official NG Youngun
did the RGB work before this board/ with other boards?

I had a similar issue and had to make a custom scart cable for my Sega Boardmaster
Yep, works well with everything except this board.

I did find that this board works with RGB when first turned on, but then once it’s been on for about an hour, if turned off and back on, it loses sync. That 3.77v figure for sync was when my monitor was blank, but when it’s first turned on sync is around 2.28v.
 

Digmac

Official NG Youngun
So the sync voltage is variable. This board is putting out anywhere between 2.2v and 3.8v on sync. I wired a potentiometer in line on sync. When I turn it on, I have to turn the pot to get sync to work properly. When I turn the board off then on, I have to adjust the pot to another spot to get sync to work again. It’s funky.
 
Did you try another monitor/TV? I knew this was a sync issue from the first post, but didn't see the thread until now. There is so much variability to sync from board to board, there's really no way to insure every board works with every screen. The voltage variability could be caps that are on their way out. Short of using a device to fully clean and replace the sync, you may have to stick with S-video or a different screen/upscaler.
 

Digmac

Official NG Youngun
Did you try another monitor/TV? I knew this was a sync issue from the first post, but didn't see the thread until now. There is so much variability to sync from board to board, there's really no way to insure every board works with every screen. The voltage variability could be caps that are on their way out. Short of using a device to fully clean and replace the sync, you may have to stick with S-video or a different screen/upscaler.
I have a set of LCD PVMs. I tried the board on the other monitor and it worked perfectly fine, but then once the monitor was on for about an hour or so, it would behave the same. Once the board was shut off and turned back on, it wouldn't sync, so it looks like my monitors just aren't playing nice with it. What's odd is that when it's not showing the video, if I plug in a BNC jack to the sync out port, it'll suddenly get the sync working. I then just unplug that BNC jack and the monitor stays synced until the board is shut off again. It's just wonky.
 

skate323k137

Jaguar Ninja
I have a set of LCD PVMs. I tried the board on the other monitor and it worked perfectly fine, but then once the monitor was on for about an hour or so, it would behave the same. Once the board was shut off and turned back on, it wouldn't sync, so it looks like my monitors just aren't playing nice with it. What's odd is that when it's not showing the video, if I plug in a BNC jack to the sync out port, it'll suddenly get the sync working. I then just unplug that BNC jack and the monitor stays synced until the board is shut off again. It's just wonky.
If you're getting a pic messing with sync out, try a 75 ohm bnc terminator on the rgb and sync outputs.

 
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