Problem with AV Out PCEngine - strange daughter board

mamejay · 07/27/2011, 06:15 AM

Hello everyone,
i have been doing a few mods on original PC Engines to remove the RF converter and replace it with a din socket to attach a AV cable for RGB and composite output.
I have already completed over 5.
I opened the latest one i got from Japan to find that it has a strange daughter board on it.
From what I can tell this is a crystal oscillator board as I compared it with another PCE I have.
The problem is I get really poor video from the rear composite av connector. Colour is terrible.
Has anyone seen this before?

Also is it possible to remove this and replace it with a stand alone crystal oscillator?
Does anyone have schematics for the PCE or any notes on the different motherboards used?

grahf · 07/27/2011, 11:29 AM

It sounds like it might be a PAL unit. Strange that you got it from Japan. Any pictures of the daughterboard?

mamejay · 07/27/2011, 11:16 PM

I will get some pics of it posted shortly. I suspect as much. I really want to get it back to original. Looks like its missing a few resistors under the motherboard.

I did not realise that they actuall;y made a white PAL PC Engine.

mamejay · 07/27/2011, 11:48 PM

There must be a way to feed back in a NTSC signal crystal as the solder points are all there. Does anyone have schematics for the PC Engine?

TurboXray · 07/31/2011, 11:14 AM

Quote from: mamejay on 07/27/2011, 11:16 PMI did not realise that they actuall;y made a white PAL PC Engine.

They didn't. But there were companies that modded PC-Engine consoles for PAL.

mamejay · 08/01/2011, 08:46 AM

That majority of parts that were removed I can get. Its just a couple of caps which I do not know the vales of. Anyone have schematics for a PCE where I can get the values?

Snow Crash · 08/04/2011, 12:24 PM

Hello Mamejay, sounds like we have the same problem! Does this look the same? I think we've got some Hong-Kong converted PCE's

mamejay · 08/04/2011, 05:21 PM

Yeah mine is the same. Mine has has the original crystal removed and a few resistors. I have used my multimeter on an unmodded board and it looks like all removed components are just resistors. I will make a list of the removed components and see if we can reverse this mod.