I'm trouble shooting a bad channel in a portable pa system. I suspect a dual OP amp is bad in one section. I want to signal trace the output of the B amp with an old Radio Shack audio signal tracer but don't know if this is feasible and won't cause damage. Thanks
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Use an oscilloscope and a tone generator and bob is your uncle. -
What model signal tracer is it?
There is pretty much no risk using one to probe the op-amp's pins. You can also measure DCV on each pin to see if that is right, or inject a test tone say 1kHz and measure ACV if your multimeter can handle DC present.
Rarely, a signal tracer's input capacitor can charge up and zap the next test point. If you are on a node with say 40VDC the cap charges and next touching a 5V node it discharges. So I will touch ground in between test points.
It depends on the sig tracer input circuit. More of an issue on tube gear where you have 300V present.
NJM2068 is pretty much a vanilla part, although the SIP-8 package is discontinued and harder to find.Comment
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Thank you. I have one of the simple Radio Shack Signal tracers to trace rf, if and af. I looked at the schematic for the tracer and it does have a capacitor in the circuitry for isolation. Worked fine to trace audio to limiter stage before going into power amp units for left and right channels. Need to trouble shoot more as I still have no channel output past this point. Thanks for the help 😊
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