Ivan Stewart steering wheel intermitten problems

[doatopgun]

First post!  I have a Ivan Stewart 3 player racing game.  One of the wheels has intermittent issues.  Most of the time it will work the whole race, but when you get to intermission, where you buy upgrades, it always stops working.  You can keep moving the wheel and after about 10 seconds it starts to work slowly and eventually it will start working at full speed.  I swapped out a wheel and it stopped the problem.  I don't have any issues like I have seen on other posts, like it only turning one way.  I would think if it were the ir, maybe one direction would work better than the other, but both directions are the same, even when steering is just starting to work.  Any help is appreciated!

[BadMouth]

Google how optical encoders work.  The info is in some threads around here, but I can't seem to find them.

Basically, you only have power and ground going to a pair of emitters (infrared LEDs on modern stuff), and then power going into the optical sensors and "output" (or "data") coming out of each sensor.  The sensors are just optical on/off switches.  They allow power to pass when light from the emitters hits them.

They are spaced so the pulses of output A and output B create a different pattern of pulses depending on which direction the wheel is spinning.

I haven't messed with old arcade wheels as much as other stuff, but you can usually test IR emitters by looking at them through a camera.
Make sure they're both lit up to the same brightness as the ones on the working wheels.  They should be fully lit all the time.  If they go out or dim, something is wrong.

Use a volt meter to make sure the sensors are putting out full voltage when triggered (I'm guessing 5v).
Test voltage going into the board for that matter.

If any of the emitters or sensors is bad, replace them.
Just cleaning them might help.  If either an emitter or sensor is dirty, it will have a harder time doing its job.
If any of them have been bumped and is not pointed in the right direction, that would also have an effect.

One other thing....bright light from other sources can also trigger the sensors when they shouldn't be triggered.
Has that particular wheel been modified in any way that would allow light from the screen to bleed into the area where the sensors are?
Could be that the upgrade screen is just brighter enough than the others to mess it up?

[PL1]

Google how optical encoders work.  The info is in some threads around here, but I can't seem to find them.

"Quadrature" is a good BYOAC search term for optical encoder troubleshooting threads like this one.


Scott

[doatopgun]

It is totally dark inside the cabinet, so it wouldn't be something from the monitor.  I will read into optical encoders and Quadrature.  Thank you for the info!