PC Engine RGB Mod / AMP

[fagin]

Just thought I would document the version of RGB MOD/AMP that I had installed in my TG16. This conversion had never given me any sync issues that seem to be so common with the PCE, various scalers and TV's.

I have since built this amp up myself and mounted inside a TENNOKOE 2 unit, so I can use the RGB mod/amp with a newly acquired LT and brand new Coregrafx.

I've not seen this type of amp before, as the usual places offer different solutions.

I've drawn a "Laymans" diagram and I'm just about to put a YT video up as well.

Hope this is of interest.

[Fudoh]

Won't work with a WHITE PCE (if used with a CD-Rom) on the Mini, unless you add a modified booster channel for the sync line.

[fagin]

Even by using CSYNC from the Ext.Bus or using a Sync Strike whilst using Composite Video?

You could just replicate one of the above individual line circuits and apply to SYNC as well perhaps.

Never tried it on a white PCE so couldn't really comment on that specific model.

[BuckoA51]

Will this work on a Super Grafx?

[fagin]

Yes.

[BuckoA51]

Nice, is there anyone over in the UK that can supply this? Is it just a modified RGB amp or does it require some internal mods to the PCE too?

[fagin]

Nothing needs to be modded from a PCE perspective, but it depends on how you wanted to implement the amp and RGB output.

There are several ways to do it:

1)Hardwire the console
2)Hardwire the peripheral
3)DIN socket console
4)DIN socket peripheral
5)Any of the above and then have the AMP circuit external (within a SCART to SCART lead)

Making the AMP is a really easy (trust me). The hardest part (or should I say the time consuming part) is dependant on how you want the RGB out to work. Hardwire is the easiest.

[BuckoA51]

My Supergrafx already has a hardwire mod, but it isn't compatible with the XRGB3. A hardwire would be fine, do you do them?

[Fudoh]

Maybe the SGX has the same problem as the white PCE. You could check your existing mod to see if only the three color channels are amped or if there's a amp channel for the sync line as well.

[fagin]

....do you do them?

I can physically do them, but it can be more trouble than it's worth commerically - so I don't bother outside of "favours".

Crack open your SCART connector and let us know what "type" of components are in there.

[BuckoA51]

Ok this is the colour booster:-


pce-rgb-amp by videogameperfection, on Flickr

I could perhaps send it to Markus in Germany if nobody in the UK can help?

[fagin]

That's not an AMP. I'd hope that you have transistors on the console end!

There is nothing on your sync (well not at the SCART end), so it "appears" to be using your console sync "un-touched"..... but the question is which one. Is it using Composite Sync or Composite Video for Sync.

If you want to send it to me to "look at" I will as a "favour".

[BuckoA51]

It's supposed to be a colour booster, without it the colours are weird.

I don't want to inconvenience you if you find it too much hassle to do for other folks, would be nice to get it working with the XRGB3 though, I've PAL consoles so don't want to go Frame Meister.

[fagin]

I thought it best to make this info public rather than keep it in PM's (hope you don't mind BuckoA51).

I just tried connecting a newly modded console I have done (my PCE LT) with the mod in this thread, to my XRGB3 and then to my DELL LCD.

Issues with warping at top of screen, but changed AFC setting on XRGB3 to 5 and it sorted it - Ran for 10mins with no drop-outs.

I then tried sending the signal from the XRGB3 to the EDGE - sync issue on the EDGE with same AFC of 5! Change AFC to auto and it won't sync for shit.

I then tried using my XRGB2+ to the EDGE - no problems and perfect sync.

Thus the issue appears to be with the XRGB3 requiring an AFC setting of 5 to output a stable PCE image, but unfortunately the EDGE hates this setting.

Is this a PCE sync issue that can be fixed or an issue fullstop with using certain "chains"...... I suspect it maybe the latter?!

[BuckoA51]

Drat, so this can't be cured at all? Maybe I'll have to look at another scaler to replace the Edge, though I know the Gefen has the same issues with not working with manual AFC's.

[Fudoh]

@fagin:

I dismissed my XRGB-3, but I have been BATTLING with the RGB PCE mod on the Mini over the past weeks and months. The booster itself is fine, but as stated before, you have to add a booster channel for the sync line. With the 3-channel booster I had dropouts, sync issues and god knows what on the Mini, but with the added 4th booster channel it's relaxed.

Give it a try I used a booster closer to the original one ( http://www.gamesx.com/grafx/pce_rgb.jpg ), but that shouldn't really matter.

I could perhaps send it to Markus in Germany if nobody in the UK can help?

Markus doesn't have a XRGB-3 for testing anymore, he's switched to a Mini as well.

[fagin]

Mmmm... I tried using the Extron RGB interface, which I assume would "equalize" the sync. It made no difference.

If I get time I will look at building an amp for the sync and see if it makes any difference to the XRGB3 and EDGE combo.

[BuckoA51]

Did you try the composite sync trick with the Extron too?

[fagin]

Yes I did.

Anyway... built a sync amp and it's no disco I'm afraid. Still don't work!

[BuckoA51]

Looks like this just isn't solvable then. Might have to look at a mini at some point I guess, though its a shame just for one machine (well, maybe 2 since the SMS has similar issues but can still be played since the screen warping isn't as bad).

[fagin]

This might sound daft, but have you tried transcoding from the XRGB-3 (VGA) to HDMI for your TV? I had mucho success doing that for a brand new SONY I bought a couple of months back.

[BuckoA51]

Don't understand what you mean sorry, that's what I'm doing with the Edge/Gefen isn't it? Neither works for the PCE.

[fagin]

I bought a brand new 55" Sony LED 3DTV in December 2011. I don't "do" retro gaming downstairs but just wanted to see what the 3 was like on my modern set. Sync issues on VGA (with the PCE). I then put a simple VGA to HDMI transcoder in between and DISCO!!

I know your EDGE and GEFEN can be used as transcoders, but they aren't actually "just" a transcoder are they.

It was just a thought in the ever eventful world of retro shizz!

[BuckoA51]

Oh I see, what model of transcoder? I've an Optoma on the way from an E-bay seller too, going to see if that works any better.

[fagin]

I'm going to try one more thing with this - just to satisfy my own curiosity - building another form of sync amp.

I'll report back.

Who knows, pink elephants may fly and this may work!

[fagin]

Some success, even if not 100%.

Fitting a 220uf Capacitor to the sync line (SCART end) improves stability alot.

There have been problems with occasional screen blanking with the CGA2VGA scaler - this solves it, what appears to be, totally 100%.

XRGB-3 and EDGE combo also shows some success. You can now actually get a picture on manual AFC without dropping it's nuts every 1 second. If you wire two 220uf in series, you can even go up to AFC 6 with the EDGE!

Overall stability is greatly improved with the added caps on the sync line. The EDGE combo is a shitload better.... but still not 100% - the odd dropout still happens.

[BuckoA51]

Close but no cigar then eh? Well it was worth a try. I get similar results on my PCE going through the Extron then CSYNC to the DVDO, almost, but still get the odd picture blank.