PC Engine GT External Controller

[MasterofBiscuits]

Hey guys. I've wired up a controller input to my PCE GT by repurposing the TV Tuner input with a mini din 8. It works great but only when I use a multitap. I've seen some people do this mod and plug the controller directly into the socket - does anyone know how this works? Have I missed a step maybe? I wired the socket directly to the vias on the back of the mainboard, perhaps I need to connect something to the controller board too?

[Necromancer]

I believe there's a board needed.  Keith will have the skinny.   

[Keith Courage]

Hmmm, I've never used the controller board for the Controller wiring. What I always do is this. Wire the new controller port wires to the HU6280. post pictures

Also, these ports fit perfectly where the existing TV tuner port is located. Have to glue/epoxy in from the backside. https://console5.com/store/mini-din-8-panel-mount-black-plastic-housing-pin-type.html

[MasterofBiscuits]

Interesting, I will try rewiring it direct to the IC. I've done the port already 

I really want to get rid of that tuner screw post, haven't managed to find anyone that has done it previously. I guess it's bonded in there somehow.

[Keith Courage]

There are small solder points on the board around the HU6280. So you can solder to those small points and not directly to the chip if you want.

[pipi]

I already have an external gamepad port for my pc engine gt thanks to the custom board that was sold on tg16mods.

What are the limits?

Can I plug a six button controller to it?
Can I plug a multi tap?

And, last but not at least...
Which are the best pc engine 2 buttons and 6 buttons controller that I can buy today?

[MasterofBiscuits]

I haven't tried rewiring mine yet, but I did have another question - is there any way to disable to power save function for the screen, which activates when using an external controller?

[Necromancer]

And, last but not at least...
Which are the best pc engine 2 buttons and 6 buttons controller that I can buy today?

All the 2-button pads I have feel pretty much the same; very comfy and work great.  The Ave3 feels very similar but a bit bigger and with a third button; 'tis a good option, but I'm not sure how many hucards really benefit from the third button.

I don't have a hori 6-buttoner, sadly, but I'd wager it's the best option.  I have Ave6 and RX pads, but they aren't great; the former's d-pad makes my thumb sore sometimes, and the latter's d-pad feels stiff and wierd.

[Keith Courage]

The only way to bypass the power screen function is to have a screen that doesn't use the built in brightness control of the Express. As far as I know anyways. So the controller port is not very useful if your express has a stock screen inside it.


I haven't tested a 6 button pad before so I can't comment on that. Although I should say that I have a found a couple controllers that don't work with the external controller port. 1 of the coregrafx pads doesn't work with it, although I can't remember if it was the grafx 1 or 2. I don't have an Express with the port in it to test right now.

[MasterofBiscuits]

The only way to bypass the power screen function is to have a screen that doesn't use the built in brightness control of the Express. As far as I know anyways. So the controller port is not very useful if your express has a stock screen inside it.

This is the PCE with the 3.5" screen. I did some poking around today and found that one of the pins that goes from the small IC on the controller board to the connector changes from 0.1v when the screen is active to 4.65v when the timeout kicks in. I have a feeling that is the timeout signal but not sure if that line has any other functions. Only one way to find out...

What would be the best way of forcing that line to always show 0.1v, preferably without lifting the pin?

Edit: OK well curiosity got the better of me and I lifted the pin and everything still works and the screen no longer dims - great success!

Edit #2: Com link port no longer works, but I can live without that.

This is the pin:

https://i.imgur.com/bbA9klY.jpg

[Keith Courage]

Ah cool, great to know.

I always just wired up the 3.5" screen to stay the same brightness level but this would let the user still be able to adjust the Brightness if wanted.

[MasterofBiscuits]

I finally got round to rewiring the controller port this weekend and running the wires direct to the test pads next to the HUC6280 has fixed the issue with my pad only working through a multitap.

[Keith Courage]

Hey, I wanted to post an update for this topic. I hadn't done the external controller port for a while and did one yesterday.

There doesn't appear to be any documentation mentioning the need for the 4 Diodes that should be installed on the internal controller board. This helps greatly with controller compatibility. Without the diodes, only certain controllers will work. 

Picture of where the traces need to be cut(or pins lifted) then have a diode placed in between. I didn't have any smd diodes on hand at the time so I ran wires to the back side of the controller board to 4 diodes and then back to the front again.

Marked with Blue

[MasterofBiscuits]

Great info Keith - thanks for posting this!