PC Engine AV Booster no video :(

I bought an old AV Booster for my PC Engine a few days ago. Unfortunately the AV Booster doesn't show a picture. I can only hear the sound.

the AV Booster is rgb modded. I don't have the cable for rgb. I can only connect it using a standard a/v cable. Maybe the guy who did the mod damaged the video port? Or could it be a problem with my PC Engine?

I hope someone could help me with that problem. I made two photos of the AV Booster:






thanks

 

Hum strange these things are generally pretty solid, have you tried to clean your hucard it looks pretty used from the picture?

I would check the solder point on the video RCA plug with a magnifier it could go overtime. Have the RF plug of your console to see if you get anything out of it?

Might be worth cleaning the pins on your port if you see any black colour on them give a good clean and blow some air on your AV Booster connector little dust can great a lot of problems.

Hope this help, no genius here but let me know how you get on.

Sabre

 

Connect those 3 AV cables to your TV, then unplug the yellow (video) plug from the booster, and touch the tip of the video on the various pins under the board... keep touching until you find whether the video goes anywhere on the board or not. Watch out you don't fry your TV by touching some DC-voltage pins.

You're lucky that the AV booster has RGB output on it; you could use it sometime. But it looks that the RGB is just tapped from the expansion port with no signal amplification whatsoever. (?) So the RGB video might be too dark and unstable.

 

thanks for your tips. unfortunately nothing helped.

very strange: I get a blurry picture from the video port when the RF cable is also connected. when I disconnect the RF cable the screen turns black again.

the television is set to AV channel all the time. It cannot switch automatically.

 

PC Engine video info:
http://www.gamesx.com/rgbadd/duorgb.php

CF

 

What exactly is an AV Booster? Is it just a device that lets you use an RCA output from a PC Engine?

 

Exactly. The problem was solved with the coming of the Core Grafx though...it had AV output right out of the box.

 

Could be that the RGB mod inadvertently disabled the composite output for video, so all you have for display is thru RGB.

 

I thought that, too. But I can't find a reason why it should disable the composite video.

 

Could this be a grounding problem?

Would be interesting to solder one end of a video cable directly to AV Booster's expansion port (composite video and ground).

CF

 

It's possible that he cut the rgb going to the encoder to avoid having two loads, which might cause brightness issues ( or he might have thought it would ).

RGB needs a sync and that might come from the encoder, it will be cleaner without the video there.

All guess work, you ought to take a look at what he did to it & maybe reverse it or get an RGB cable.

smf

 

I suspect that the orange, green and yellow wires are R, G and B tapped directly from the expansion port. The brown wire might be +5V. The red and black looks like composite video and ground. I am only guessing.

Clean sync and composite video with sync are both available directly from the expansion port (before amplification).

I have a feeling that nothing as been cut on purpose, and that there are no encoders on the AV Booster PCB (?). Looks like there is a transistor amp for the video in front of the yellow connector (next to TP4). Maybe that transistor or one of the caps are defect.

Would be interesting to see a close-up photo of the PCB without the tape

CF

 

I think I'm not able to fix this problem by myself. so I gave the unit to a friend from a games shop. He will check it.

Thanks for all your help. I will let you know how it goes on.

 

I've got the AV booster back today. the AV booster works fine with the PC Engine of my friend. He borrowed me his PC Engine to check it with my TV. It works fine with my TV, too.

So there must be a failure with the expansion port of my PC Engine.

 

I opened up my PC Engine and it seems to be modified. There are much cables on the backside of the pcb. I don't know for what is it good for. Here are some pictures:

 

Probably PAL RF modulation. Need better pics

 

I tried to make better photos, but it's not easy because there are so much wires and I cannot completely remove the pcb nearby the rf unit