- Joined
- Jan 7, 2013
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- 4,218
Mainly posting this as documentation in case someone has this problem in the future and ends up scratching their heads like I was.
I recently grabbed a couple of rev1 hyper64 mobos (one of which is on its way to Panda island to live amongst the pulstars). Lucky for me they came with the extra 4 pin looms for stereo sound and power support, and a pair of samurai shodown 64 carts.
I get everything hooked up to my supergun/PVM, and there's wavy interference over the picture. Picture itself is OK, but diagonal ghosty-looking lines are "rolling" across the picture.
I think, OK, maybe this is drawing a lot of power, and the supergun I'm using has the video lines running close to the (unshileded) power lines. I'll split those up. So I take the time to rebundle the wires coming from my JAMMA connector and isolate the power from the video wires. No dice; same bullshit interference in the video :/
Around this time I start googling. I find a couple threads where people bridged logic ground and earth ground on the power supply to "fix" similar issues. To me that didn't sound like a very good idea, but it inspried a little more tinkering. I pull out my volt meter, set it to ohms, and probe the jamma ground pins and the metal case of the hyper64 mobo. Bingo... continuity! Still not wanting to bridge the DC ground and AC ground (signal and earth ground) at the PSU itself, I decided I'd just earth ground the metal casing of the hyper64 motherboard. I'll be damned if that didn't fix it; video is perfect.
This -may- be more of an issue with the PSU itself (HAPP power pro), as I've found other cases of that being the case. This same supergun has similar interference with CPS2 boards, but not -nearly- as bad as it was with the hyper64. It really hasn't bothered me at all with other boards. Down the road I may try a different brand of PSU, as my other supergun uses a "meanwell" PSU and never had problems like this with CPS2 (or any other) boards.
TL;DR, I earth grounded the metal case of my hyper64 mobo and it fixed my video problems.
I recently grabbed a couple of rev1 hyper64 mobos (one of which is on its way to Panda island to live amongst the pulstars). Lucky for me they came with the extra 4 pin looms for stereo sound and power support, and a pair of samurai shodown 64 carts.
I get everything hooked up to my supergun/PVM, and there's wavy interference over the picture. Picture itself is OK, but diagonal ghosty-looking lines are "rolling" across the picture.
I think, OK, maybe this is drawing a lot of power, and the supergun I'm using has the video lines running close to the (unshileded) power lines. I'll split those up. So I take the time to rebundle the wires coming from my JAMMA connector and isolate the power from the video wires. No dice; same bullshit interference in the video :/
Around this time I start googling. I find a couple threads where people bridged logic ground and earth ground on the power supply to "fix" similar issues. To me that didn't sound like a very good idea, but it inspried a little more tinkering. I pull out my volt meter, set it to ohms, and probe the jamma ground pins and the metal case of the hyper64 mobo. Bingo... continuity! Still not wanting to bridge the DC ground and AC ground (signal and earth ground) at the PSU itself, I decided I'd just earth ground the metal casing of the hyper64 motherboard. I'll be damned if that didn't fix it; video is perfect.
This -may- be more of an issue with the PSU itself (HAPP power pro), as I've found other cases of that being the case. This same supergun has similar interference with CPS2 boards, but not -nearly- as bad as it was with the hyper64. It really hasn't bothered me at all with other boards. Down the road I may try a different brand of PSU, as my other supergun uses a "meanwell" PSU and never had problems like this with CPS2 (or any other) boards.
TL;DR, I earth grounded the metal case of my hyper64 mobo and it fixed my video problems.
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