PC-engine: horizontal shift with RGB

OK, so I made an RGB amp for my PC-engine using this:



And I know, it's an ancient design and there's a newer, better one around. The amp works fine, the colors look good, but my image has a left horizontal shift which leaves a black bar to the right of the screen. I have a PAL TV, by the way. From what I understand this is quite common with RGB and it's some kind of sync issue.



What is my best course of action here? Blame the amp, the cable or the TV? Could building the newer, better amp improve on this?

The cable is wired up like this:



I'm also a little confused about the composite video / composite sync. Do I need both? Most guides seem to leave out the composite video and just use the sync to scart pin 20 (composite video input), unamplified. But that's not supposed to work.. or?

 

It's both the TV and probably the PCE itself. NTSC and PAL have very similar but not exactly the same horizontal timing. The PCE is centering it's video too early in the line for how your TV is calibrated. I'm unsure whether this is due to a difference in PAL safe area or something or if your TV's center is off, but you could try adjusting the TV's H position and size if position isn't enough. There isn't another feasible way to fix this since that would require delaying the video 10s of pixels, or delaying sync 1 whole field/frame - 10s of pixels.

 

OK, thanks! I guess I can live with it..

 

Is it a PAL or NTSC signal from the PCE? Any other inputs you can use?

You may be able to adjust horizontal position internally or via Service Menu - what TV?

 

Something sorta interesting. I recently modded my 3do for rgb. It had a pot that allowed me to adjust the horizontal shift. Not sure if this is related one bit, or if its feasible to make such a device for what you are trying to do.

 

The mod/DAC board did? How far can you adjust the picture?? It must be delaying a digital sync signal through an RC integrator circuit / low pass filter. In this situation sync is already triggering too late so delaying it any less than a line will only make things worse. This is possible, but not without a complicated circuit because simple RC "delay circuits" aren't symmetrical so they'll start distorting the duty cycle, and if you try to delay a logic state longer than it's own period the integrating signal won't pass the theshold in time and get stuck in a single state.

Also this would be slightly more complicated for the PCE as there isn't a digital sync signal, so it would have to be separated first. Delaying one line would shift the screen up one line.

 

The PCE sends out an NTSC signal, my TV is PAL. Before I tapped the RGB, I tried tapping composite video just to see if the PCE was working at all, and from what I can recall there was no horizontal shift then.

I've also tried the PCE with my LCD TV, and there's the same shift. I don't think there's a service menu on my old CRT TV, no. I can't find the model number, and I don't have the original remote so..

 

Yes the mod board did. I got it from here: http://www.otakus-store.net/en/modding-kit/279-3do-rgb-modding-full-kit.html

When I first turned the unit on, half of the picture was shifted to the left side of the screen. Turning the knob brought it to the middle. Everything you talked about it, is beyond my knowledge