Commodore 128 Issue with Control Port 2 is Utalized

[robert_sissco]

So I have a Commodore 128 (not the D model, the flat model) and it works great, but when I plug a RetroRadionics Arcader joystick into Control Port 2, I lost the 9, 0, I, O, J, K, N, M keys, two columns of keys on the keyboard. I use any other joystick in Control Port 2, or the ArcadeR joystick in Controller Port 1, no issues with the keyboard. The issue is present in both 128 and 64 mode.

I have not seen anything on this, I was just wondering if anyone know what this could be. I have contacted them and hope to hear from them soon, this is jus an odd issue I have found.

 

[gertk]

The keyboard matrix with the C64/128 is shared with the joystick ports. So my guess is that the RetroRadionics Arcader is loading some pins of the joystick port and thereby interfering with the keyboard.

Try for example holding a standard joystick in port 2 to one direction and then typing anything on the keyboard, it will interfere with keyboard operations too.

 

[daver2]

From the service manual (http://www.zimmers.net/anonftp/pub/...ommodore_128_128D_Service_Manual_1987_Nov.pdf) I can see that your letters and numbers correspond to Pin 16 of the keyboard connector (see page 51).

Looking at the schematic on page 66, the keyboard connector (CN5) pin 16 is connected to COL4.

COL4 (in turn) is connected to Control Port 2 (CN4) pin 6 which is FBTNB. So I would check that button for a short circuit (as being the most likely cause).

Control Port 1 (CN3) pin 6 is connected to ROW4 so, if there was a short circuit, I may have expected some observable effect on the keyboard if this controller was moved from CN4 to CN3 - just not perhaps a complete column of keys...

It gives you somewhere to look at any rate.

I would check for a short circuit from all of the button outputs to both 0V (pin 8) and +5V (pin 7) and check for correct operation with a multimeter whilst you are at it. You can perform this check on the joystick controller itself on the bench with a multimeter set to read resistance.

Dave

 

[robert_sissco]

@gertk it just seems odd to me is all since I have no issues on the C64 or Vic20 with it plugged into either of them. And no characters appear on the screen when trying any of the directions or buttons on the joystick.

@daver2 Thank you, that is very useful. I just switched to non ArcadeR sticks in the meantime, but this is a good starting point. I will give it a shot this weekend when I have time to sit down to some serious research into this.

 

[view836]

@gertk it just seems odd to me is all since I have no issues on the C64 or Vic20 with it plugged into either of them. And no characters appear on the screen when trying any of the directions or buttons on the joystick.

@daver2 Thank you, that is very useful. I just switched to non ArcadeR sticks in the meantime, but this is a good starting point. I will give it a shot this weekend when I have time to sit down to some serious research into this.

I know this thread is a little old but when I encountered this problem I found it was caused by the auto-fire feature of the ArcadeR joystick. When I turned auto-fire off everything was fine.