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ramapcsx2 / gbs-control

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Scrambled or no picture with a jamma setup #108

Open UnknownMK25 opened 4 years ago

UnknownMK25 commented 4 years ago

15854248070522225595255429301172 15854248543737527407276644839733 When I hook this up to my jamma set up I either get a scrambled picture as seen in the pic or I don't get any picture at all. It depends on what board is plugged in. The picture will occasionally come in and stabilize, but then just scrambles again. I added the 100 Ω resistor between sync and ground but that didn't make a difference. I also have the pots turned all the way to the left. I tried a 5v 2A and a 12V 2A power supply and that didn't make a difference. Is there something else I can try?

wally86 commented 4 years ago

I'm having a similar issue with my setup. What do the pots do? Mine are all in the middle. I have only used a 5v 2a plug. Can a 12v 2a help at all?

ramapcsx2 commented 4 years ago

No. Please don't try any more different power supplies. 5V 1 to 2A suffice!

This is a sync signal only problem, and you should investigate what kind of sync your boards put out. https://github.com/ramapcsx2/gbs-control/wiki/Arcade-Boards

UnknownMK25 commented 4 years ago

It was my suspicion it had something to do with the sync. Can you explain what kind of modification I would need to make to resolve the issue?

ramapcsx2 commented 4 years ago

I cannot debug your setup from here. You need to find out how your board connects to displays. Do you have a super gun? Did it come with a manual?

UnknownMK25 commented 4 years ago

No manual, it's simply a jamma test rig I built. The rgb is simply coming off the jamma harness and it's just the typical r,g,b,vid sync,gnd, connected here: 15854875776552415003531550699277 Everything worked fine before the mod and works fine on a CRT, it just seem post mod that the issue is present.

ramapcsx2 commented 4 years ago

I still can't debug this. I don't have access to your setup and can't see how the sync signal looks like.

UnknownMK25 commented 4 years ago

I don't know if this helps any but can you at least tell me if my settings were correct based on my hardware? This is my chip: 20200331_034916 These were the settings I used: 20200331_041135

ramapcsx2 commented 4 years ago

Settings are correct, but I dislike the metal screws. It might be no issue, and surely unrelated, but the metal screw heads could short out stuff.

You need to help me out a little.
Right now, I only know that you have some arcade board(s) and use the Jamma sync signal directly into the GBS. It would help if you searched the web for one of your boards with the issue, and find out a bit of info on what kind of sync it may produce. One important bit is the horizontal frequency, for example. Is it a typical 15kHz signal, or something else?

UnknownMK25 commented 4 years ago

I really can't seem to find anything regarding sync output on the boards I've tested but I believe they all output at 15khz and I found this bit of info, not sure if it helps: "Original Arcade boards that run Standard (CGA) run TTL, that means 3 to 5 volts video and sync outputs, terminated at either 390 ohms or 1Kohm". I also spoke to a member of the shmups and klov boards and he indicated that he has run multiple arcade boards on it without issue so there must be something I'm doing wrong.