[R-390] OT

[Scott, Barry (Clyde B)]

Can someone give me some advice concerning some optoisolators?  I built an interface to go between the computer to my Knwd TS440.  It uses a MAX232 level converter and four NEC PS2501 optoisolators.  The project did not work and, after finding a bad solder joint, the MAX232 seems to be doing what it should, but all the optoisolators seem to be blown.

I was careful handling them (assuming they are somewhat static sensitive), but all of them appear to be bad.  The diode part checks okay with the Fluke DMM's diode-checker mode, but the EC junction doesn't seem to be working.  I've ordered replacement isolators, but before I start playing with them I have a couple of questions.

Is it possible (or safe) to check the EC junction using the Fluke's diode-checking function?  Unless the LED is forward biased, should I see anything across this junction with the Fluke?

How "rugged" are these devices?  Given that I strap a ground wire around my wrist and have my feet on the concrete floor, should this be sufficient to keep from "blowing" them?  Are they as rugged as, say, a 2N2222?

Thanks,

Barry(III) - N4BUQ

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