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previous: Doc Measure the resistance between the ... -- 12/14/1999 6:36 PM

Re: Question about Opto (from New Sensor)

12/17/1999 1:31 AM
moocow	Re: Question about Opto (from New Sensor) I had the same problem with the New Sensor optoisolators. The shrink tubing is much tighter than the original Fender components, so you can't just look inside and tell where the leads go. Unfortunately, the photoresistor side measures over 20M, so this trick didn't work with my meter. I wound up putting the leads in series with a voltmeter and measuring a high voltage. The photoresistor side will allow some voltage to get through to a digital voltmeter, but the neon bulb side won't. When I installed it, I left the leads uncut in case I had made a mistake. It only takes a couple of minutes to solder in place anyway, so you stand a 50-50 chance by just guessing. After I verified that the installation was correct, I went back and trimmed the leads. The method worked, but there is a dot marking one side of the New Sensor optoisolator. Unfortunately, I didn't write down if the dot means bulb or photoresistor !

12/17/1999 1:31 AM

moocow

Re: Question about Opto (from New Sensor)

I had the same problem with the New Sensor optoisolators. The shrink tubing is much tighter than the original Fender components, so you can't just look inside and tell where the leads go. Unfortunately, the photoresistor side measures over 20M, so this trick didn't work with my meter. I wound up putting the leads in series with a voltmeter and measuring a high voltage. The photoresistor side will allow some voltage to get through to a digital voltmeter, but the neon bulb side won't.

When I installed it, I left the leads uncut in case I had made a mistake. It only takes a couple of minutes to solder in place anyway, so you stand a 50-50 chance by just guessing. After I verified that the installation was correct, I went back and trimmed the leads.

The method worked, but there is a dot marking one side of the New Sensor optoisolator. Unfortunately, I didn't write down if the dot means bulb or photoresistor !