Pc Engine GT / TurboExpress clean video / audio output connection

[pipi]

Hi all,

I hope you are all well during these crazy days.

I am very happy about my Pc Engine GT modded LCD screen and it also features a video output.
I would like to complete the work and get the signal out of the case (the wires are ready) but I would like to choose a solution that is not invasive drilling the case or ruining in an irreversible way the existing ports.

I know that someone was able to do a mod that will allow the audio exit on the GT to output also video (using this kind of cable: https://store.retrofixes.com/collections/upgrade-diy-kits/products/trrs-3-5mm-to-gold-rca-jacks-6-used-with-atari-jr-and-nes-upgrades?variant=36089892746 ) but I would love to have more details about how to do it because while I can solder and I am mildly confident with modding I am not really an expert.

If you can suggest how to tackle this with some detailed steps or also (this would be dream) one or two pictures I'd be very happy and grateful.
This would indeed keep me busy and entertained for a bit during the quarantine.

Stay healthy and stay safe!

[Keith Courage]

It depends on how the Screen upgrade was done. I'd need to see the PCB board to see if it has two transistors on it. If there is only 1 for the larger screen only, then there won't be a way to output video to the TV without adding another transistor to the video board.

Well, there would be a way without adding another transistor but you would have to put a switch on the system to be able to turn the new screen on and off because if both signals run at the same time from 1 transistor the quality suffers a lot.

The link port at the bottom of the system can be re purposed to be used as an AV out by cutting the traces on the PCB that are currently going to said port but it is only two channel. Meaning it could only be used for Video and mono audio.  I like to use this port for video and use the existing headphone out for the audio. This is much easier than installing a 1 port solution. If you really want all to come out of one port, then you will need to remove the link port entirely and then solder wires for the video to the new port plus take audio from the headphone jack for it.

[MasterofBiscuits]

I was planning to do this when I did my LCD mod, but in the end I decided if I'm going to the trouble of wiring up AV out I might as well do it properly and just use RGB. So my GT has an internal RGB amp board and a 9 pin mini din output which is the same specs as the Megadrive 2 cables. This also has the composite signal included so you could use composite if you wanted (eg if your TV didnt have RGB input).

It gives a really nice picture and much better than composite would.

I put the port where the AC jack originally was since mine has a lithium battery now.

[bdoi]

I was planning to do this when I did my LCD mod, but in the end I decided if I'm going to the trouble of wiring up AV out I might as well do it properly and just use RGB. So my GT has an internal RGB amp board and a 9 pin mini din output which is the same specs as the Megadrive 2 cables. This also has the composite signal included so you could use composite if you wanted (eg if your TV didnt have RGB

Looks great!
how did you do your rgb mod?

[MasterofBiscuits]

I was planning to do this when I did my LCD mod, but in the end I decided if I'm going to the trouble of wiring up AV out I might as well do it properly and just use RGB. So my GT has an internal RGB amp board and a 9 pin mini din output which is the same specs as the Megadrive 2 cables. This also has the composite signal included so you could use composite if you wanted (eg if your TV didnt have RGB

Looks great!
how did you do your run mod?

I wired the RGB and Csync inputs directly to the HUC6260 chip, and the 5v and GND to nearby capacitors - these go to the input on the RGB amp. Then just wire the output from the RGB board direct to the mini din socket. I wired it up following this diagram

http://members.optusnet.com.au/eviltim/gamescart/mega2.png

from here: http://members.optusnet.com.au/eviltim/gamescart/gamescart.htm

Since I'd done the composite 3.5" screen mod with a dual output composite board, I took the composite signal from there. I think this wiring would still work without composite video in there so this is optional.

It's not too difficult!

[pipi]

Hi all and thanks for all the help.

MasterofBiscuits's mod looks like a million bucks!
What kind of RGB amp did you use?

For a lucky situation I am now the happy owner of a RGBDRV and IPS screen :O
I am not sure if using it in the PC Engine GT or in my SEGA Nomad.
I suspect that the Pc Engine will be the chosen one because I read information about artifacts on the nomad with RGBDRV.

Does anyone have experience with this solution on the Pc Engine GT?
A tutorial would be VERY appreciated

[MasterofBiscuits]

Hi all and thanks for all the help.

MasterofBiscuits's mod looks like a million bucks!
What kind of RGB amp did you use?

For a lucky situation I am now the happy owner of a RGBDRV and IPS screen :O
I am not sure if using it in the PC Engine GT or in my SEGA Nomad.
I suspect that the Pc Engine will be the chosen one because I read information about artifacts on the nomad with RGBDRV.

Does anyone have experience with this solution on the Pc Engine GT?
A tutorial would be VERY appreciated

By coincidence I just built an RGBDRV/ IPS machine this week (and sold it!). Here are some pics:

In both machines I used the RGB amp from oldskoolconsoles.com - it uses the THS7374 IC and works well.  https://www.oldskoolconsoles.com/product-page/pc-engine-rgb-7374-mod-kit

You will also need one of these to control the OSD https://www.sparkfun.com/products/8184

The picture is incredible with the IPS screen. I have one more board which I will be putting in another of my machines and keeping.

If you would like a tutorial I can make one when I install the other board (probably next week).

[hard_gb]

Well, there would be a way without adding another transistor but you would have to put a switch on the system to be able to turn the new screen on and off because if both signals run at the same time from 1 transistor the quality suffers a lot.

I'm sorry this post is "waking up" but I was very interested in doing two mods on my GT.
I want to adapt a connector to use the external control and I want to be able to send the video signal to the link function jack (connector at the bottom of the GT).

But I saw that you need to install a switch so that the screen does not go into safe mode and turn off.

How should I do this installation, I mean, what are the points that I should connect to this switch.

Thanks for the help