View Full Version : PCJR Joystick Pot Value

July 10th, 2012, 05:38 AM
I have been trying to find out the potentiometer value for the PCJr joystick because I read an intimation that they do not use the standard PC 100k pots. Does anyone know the pot value?

Great Hierophant
July 10th, 2012, 06:39 AM
It is 100K pots in the PCjr., but the timing may be different because a 64-128KB PCjr. is slower than a PC.

July 10th, 2012, 08:16 AM
I have your email but I have not had a chance to get to the technical reference to look it up.

Patience ...

July 10th, 2012, 08:48 AM
Gah.. yet another person just signing up to see how much something is worth?! Grr. ;-) j/k Are you trying to repair something or build one from scratch?

July 10th, 2012, 09:05 AM
I'm looking at converting them.
I have 2 i want to wire up through a box then into an Apple IIe and one I'm trying to wire up to an Atari 5200.
I went through the AtariHQ docs about converting a regular PC analog stick to the 5200 which recommends using .22uF caps from H Pot and V Pot to to Ground. Since I have some converted keypads to work with a Wico Y cable, I arranged the pins to match up with the Wico Y cables I have. On the games I tested, movement is invariably up and to left on the screen despite adjusting the trimmers.

I have yet to start the Apple IIe conversino so I thought I'd better find out more information after wikipedia (yeah, I know) suggested that the PC Jr stick used non-100kOhm pots.



July 10th, 2012, 06:51 PM
You can download the PCjr TechRef at my site (http://classiccomputers.info/down/IBM/IBM_PCjr/IBM_4862_PCjr_Technical_Reference_Nov83.pdf) - I'm assuming that it has the information that you're seeking.

July 11th, 2012, 07:02 PM
You can download the PCjr TechRef at my site (http://classiccomputers.info/down/IBM/IBM_PCjr/IBM_4862_PCjr_Technical_Reference_Nov83.pdf) - I'm assuming that it has the information that you're seeking.

That confirms the first response. It is indeed a 100kOhm pot. I'm going to go back and double check my connections and my caps because I simply must have just messed up somewhere.

After a recheck and a little work, everything is working fine. The joystick is working perfectly on the old 5200!