john35thss

This afternoon was looking at my assortment of optisparks that came off running motors. Either I toss them or use them.

I would like to use the rear optical portion of the unit if I was sure it was ok.
Is there any way to test the optical pickup off the car.


John

Guest47904

Sure there is. Put 12 volts on pin C and ground on pin D. Then measure from pin D(ground) to pin B for 0 to 5 volts when rotated. And from pin D to pin A for 0 to 5 volts when rotated.

john35thss

Thanks Speedy, still hard to believe how many posts are on this forum almost couldn't find this thread.

Are those pins marked A,B,C,D.

John

Guest47904

You know I'm not sure. You could use the wire colors from the connector on the car. speak up if you need the wire colors.

john35thss

wire colors would be great.

John

Guest47904

Pink/black is ground. Red is +12. Purple/White is high res. and the Red/Black is low res. Both will vary from 0 to 5 volts when rotated. One will change faster than the other so rotate slowly or your meter will not keep up.

jeremyferguson

I know this is an old thread but I'm hoping to get clarification on what is discussed above. I have two opti's I've been bench testing per the above procedures and I think I might be missing something. Between ground and terminals A and B I'm getting well under a volt, but the numbers are going up and down as I spin it. One opti goes between .005 and about .3 volts (on DC setting) on both high and low res. While the other opti goes between about .010 and .8 volts on both terminals.

are they both toast? Shouldn't the voltage go up and down between 1-5 volts on both, just at different speeds?

Thanks!

GaryDoug

12 power goes to pin C, ground goes to pin D.
Normally there are resistors inside the pcm, one going from for pin A to 5vdc and another going from pin B to 5vdc.
For simple testing purposes, you can connect the resistors to 12v instead of 5v. Resistor values inside the pcm are about 3900 Ohms but you can use anything from 1000 Ohms to 10,000 Ohms and get good results. Measure with a scope at pin A and/or B. Without the resistors, you will get about zero volts at both.

jeremyferguson

Thanks for that clarification Garydoug!! Much appreciated!!