Hi I need some help;
The game port on my Apple IIe is not working correctly
The horizontal axis on pin 6 is working fine and I can read 0-255 from the joystick.
The vertical axis on pin 10 only reads 255 regardless of stick position.
I rewired the pins to check the joystick and when swapped I still get the same results.
I have also swapped out the Ne558 quad times and the 74SL251 Multiplexer from another Machine, still the same issue.
( I have ordered two new chips anyway as the same fault could be on the chips ?)
Anyway I would appreciate any sort of assistance but please bear in mind I am not an electronics engineer, I can work a multimeter though.
Note it is only one axis that is not working, the buttons work fine.
Hello Trueman,
welcome to the board....
related to the gameport there are some components along with the NE558:
the 4 capacitors C34, C35, C37 and C40 ( each 22nF or in other notation 0,022µF )
as well as the 4 resistors R21, R22, R23 and R24 ( each 100 Ohms ).
The 4 capacitors are simple ceramic disk capacitors nonpolarized....
so may be at the second axis one of the resistors or one of the capacitors might been damaged.....
Resistors and capacitors are very cheap so changing them all will be possible with cost less than 4 or 5 dollars....
another possible trouble might be damaged wire inside of the joystick..... after years that wires might have gotten worn out and on might have broken inside of the isolation coat.
So I'd recomennd first to make continuity check inside the joystick with multimeter before changing
the components.....
sincerely
speedyG
The capacitors from the platinum Apple iie motherboard and the older iie motherboard are interchangeable.
Thanks for the info on the capacitors, I think I will remove the 558 timer and then measure the resistance to the 100 ohm resistors, this should reflect the value from the pots. I could then try the other side of the resistors where the capacitors are, I would expect the values here to be pretty much the same as long as the 558 is off the board. The Joystick is definitely good as I have it connected through a breakout board so it could be diagnosed. If there are odd results on the capacitor side of the resistors I will replace them with new ones I already have.
Regards
Trueman
All Fixed, it was the 558, replaced and now Load Runner works, I will now get to play the games I played in 1982 !
Thanks for you kind assistance.
Regards
Trueman