I just had (I believe) my Unilite Optical Module fail. I want to make sure I'm testing it right. Off the car I'm doing the following:

12V + to red wire
12V - to brown wire
Test voltage at green wire with the optical slot covered and open (with credit card or the like).

On the green wire I have effectively no voltage. Assuming I did the test correctly, this means it's toast. Which is strange as it's lasted probably 10+ years (I run the 6AL and the protection circuit).

I'm replacing the very expensive 605 module with what seems to be a more cost effective unit, the 6100M. I'd love to test it before putting it in the car, so let me know if I have the procedure down correctly.

Thanks.

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I never found a reliable test that could be done in the car; I just put in a new module.
One thing I learned was Not to do electric work around the coil etc without disconnecting the Mallory.
I have since moved on to the 1-2-3 Ignition. I have a new Mallory Voltage Spike protector, a carbon brush, and a good 605 module.

I never did this test myself; but the manual says something like this. Remove the cap and do a voltage test. By blocking the optical module with a credit card. A certain threshold must be achivied. I do have the instruction sheet

Just an FYI, there's a pertronix replacement for the mallory.
I use older points redcaps and a pertronix, I have one stitting here in my display cabanet.