Sync issues on all systems

[backforwardpunch]

I have been having issues displaying any image due to sync on every system I have. I have my systems mostly wired up through VGA using H+V sync. All of the H+V systems do not display at all and give NO SYNC messages. I have a PS1 where I used a sync separator to split composite sync to H and V, and it displays for about 20 seconds and then goes back to the NO SYNC message. Additionally, I have a PC Engine using SCART that has intermittent issues with sync. Am I missing something? Does OSSC not accept H+V sync? Is the pinout on the VGA input somehow non-standard?
Any help would be appreciated.

[BuckoA51]

OSSC does accept H+V sync, but this is a strange way to connect things up. Can you try SCART instead? The SCART socket is better for these machines as it includes the low pass filter.

[backforwardpunch]

I can, but I have the systems wired up now using VGA for an RGB monitor. I do have a scart cable for the PC Engine, and it’s also giving SYNC issues as well. Just thought maybe it was some overarching issue or setting that I would need to look at.

[marqs]

Which kind of circuit you use to split sync to H+V? I’ve personally used ISL59885 in similar applications where it has worked reliably, and it was ok with OSSC too when I tested it. Are these systems otherwise directly connected to ossc or are there other devices in the chain? There has been a couple cases where a bad quality PSU (not necessarily the one powering ossc) in closeby outlet has caused bad enough interference to screw up sync. I’d guess your problem is either that or a defective board.

[BuckoA51]

Have you turned on Sync LPF when using your PC Engine?

[backforwardpunch]

@marqs
I used the LM1881 to separate the sync from composite on the PS1. I also have a Genesis (wired through VGA with H+V sync) and a SNES wired the same way. None of the H+V sync systems display anything, and they all show NO SYNC. THe PS1 as stated before, works briefly.

@BuckoA51
I tried with Sync LPF as well. The NO SYNC message comes on and off.

[BuckoA51]

Does LM1881 actually split sync, I thought it just cleaned it?

[marqs]

LM1881 does not separate sync to H + V, but to C (c-sync) + V. You should therefore use RGBS mode of AV3 input instead of RGBHV.

[Piffles]

I am having the exact same issue.
It’s not picking up the synch of any of the SCART connections I have in AV1.

It picks up the PS2 in AV2 (with the typical red yellow white connections) though it still doesn’t display anything aside from the test screen regardless of the setting.

I do have the official SFC SCART cable for Super Famicom, and the SCART cable for the PC-Engine RX.

The OSSC is connected to the TV via a HDMI to DVI adapter.

Any thoughts or possible ideas to remedy this?
I can take pictures of anything for further troubleshooting needs.

[backforwardpunch]

@marqs
Thanks! That solved my issues with PS1, PS2 with the sync. RGBS is displaying properly. Any ideas on the Sega Genesis or SNES?

http://www.gamesx.com/avpinouts/genesisav.htm
Appears to be just labeled SYNC, which I am assuming is H+V. Am I wrong?

[backforwardpunch]

Hey, also just tested with my SNES, RGBS worked on there as well! Only one left to solve is the Genesis, as that still won’t display at all. Do I need to split out the sync for it?

[paulb_nl]

It picks up the PS2 in AV2 (with the typical red yellow white connections) though it still doesn’t display anything aside from the test screen regardless of the setting.

I do have the official SFC SCART cable for Super Famicom, and the SCART cable for the PC-Engine RX.

You should get a black and white noisy image with the yellow composite video cable connected to the green AV2 input. Can you try it on a monitor?

The official SFC RGB cable is JP21. Did you rewire it for SCART?

[marqs]

http://www.gamesx.com/avpinouts/genesisav.htm
Appears to be just labeled SYNC, which I am assuming is H+V. Am I wrong?
That is TTL-level composite sync. I don’t recommend wiring it to LM1881 since the chip is meant for extracting sync from video-level composite/luma signal – you might otherwise run into issues. It should be possible to wire that SYNC directly to VGA H-pin to be used with OSSC AV3 RGBS.

I am having the exact same issue.
It’s not picking up the synch of any of the SCART connections I have in AV1.
Please make a separate topic since your issue is not related to using VGA/AV3.

[BuckoA51]

Appears to be just labeled SYNC, which I am assuming is H+V. Am I wrong?

Unless there’s two sync outputs it’s combined/composite sync not H+V.

I can, but I have the systems wired up now using VGA for an RGB monitor.

Wait a sec, that won’t work anyway, since VGA monitors don’t accept 15khz.

[backforwardpunch]

Hey, I get the confusion, its an arcade monitor, so it accepts 15khz. Forgot to mention that. It’s currently wired to the H pin on VGA and displays fine on the monitor, just doesn’t get picked up on the OSSC. I can wire up a sync separator if it wants separate sync, I guess if LM1881 isn’t what I want, can you suggest an alternative?

[Author]

Posts