PC Engine with RGB modded Interface Unit

[Nioreh]

I have the white PC Engine and CD with the interface unit RGB modded.

Has anyone gotten this console to work properly? I get sync issues, with dropouts and the top part of the image being wavy. I’ve seen other reports of this wavy thing on BVMs with certain consoles that have crappy sync output.

I tried running it through the sync strike. It got a little better, but still drops out for a second maybe every 10 seconds or so. That is the best I have been able to get it playing with the settings. (Firmware is 0.78a)

With the sync strike and the AV3 interlacefix option turned on, the wavy top disappears. Dropouts keep happening though.

[BuckoA51]

Is your analogue sync LPF set to max?

[Nioreh]

Yeah, I have it set to max

[BuckoA51]

Who modded your interface unit?

[Nioreh]

It is by an ebayer called 8bitterz.

I have opened the unit up and checked the wiring. It seems the RGB lines go from the expansion port of the console through one of these amps:

And the sync signal I think is straight from the expansion port (Can double check later, at work at the moment). Does the sync line need anything inline with it to be up to spec?

[BuckoA51]

Hmm, I’m uncertain but usually sync on PC Engines is kind of wonky (if you think OSSC is problematic try going back to the XRGB3 days)…

Someone like Voultar would be the person to ask, I’ll see if I can get in touch with him.

[BuckoA51]

Ok, Voultar got back to me, he says “If csync is being grabbed directly from the expansion port and not buffered out, it isn’t going to get along with most equipment”. Please can we have a picture of the expansion port wiring?

[Nioreh]

Thank you. It looks like I was mistaken. Sorry for confusing everyone. The sync line comes off the same connector as the sub board for the A/V out, which leads me to believe the sync is actually composite video?

The yellow wire on the left is going from this connector pad directly to the RGB out sync pin (8 pin DIN connector, looks like it’s wired the “standard” way). The black, white and red wires seem to be ground plus left and right audio.

Should I maybe rewire this to use the sync out from the expansion connector, with something on the way? I see that Voultar sells a board for the PC engine with buffering for sync and 75 ohm. The wiring is quite horrible on this mod, and the AMP is just kind of hovering on top of everything, so I’m thinking about redoing the mod anyway.

Here is the RGB amp used in the mod

Here is what is soldered to the expansion pins. Only R, G, B comes off here. Plus +5V and ground.

[BuckoA51]

Images are kinda dark I’m having trouble making it out but I’ve asked Voultar again 🙂

[Nioreh]

Yeah sorry about the image quality. I have no good lighting and only my cell phone. But the important part that you hopefully can see is the yellow wire on the first image. That is the bottom side of the board, on the other side is the connector that goes of to the A/V out sub board (with composite
and audio out). It is tapped off of that connector, with nothing else on the line.

[BuckoA51]

Voultar has spoken:-

“The board placement is horrible. All sorts of things are going to couple into his video. Honestly, it just needs to be completely redone, Aand that board needs to be positioned in a healthier area.”

[Nioreh]

Haha, ok. I guess I’ll order Voultars PCE board and redo the mod. Thank you!

[SnoopKatt]

Yikes, wish I saw this thread last week. I purchased a modded pc engine from 8bitterz as well and I’m having the exact same problem. Major audio hum as well. Hoping he’ll give me a partial refund to buy a better rgb board.

[SnoopKatt]

Whoops double post

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