Cool. Everyone quit PMS-ing.
For a solder/desolder station **broken link removed** these are not too bad. I have the BK 6000 which isn't made any more, but I got hot air, de-solder hot iron and an arm.
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Justin does have an application for a scope. Fix the guitar thigy. He should try to get a schematic and/or find out what the cost of repair is from the manufacturer.
Then maybe try to determine what OP amps are used. Maybe one of the things he could do, is check the offset and he difference of the +-inputs of all of the OP-ams.
That's something that could be done now with a meter.
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Troubleshooting when you have a schematic generally involves injection and/or tracing once the power supply and power supply ripple have been checked.
You generally start in the middle and bisect the failed stages. This results in the fastest fault finding. With stereo stuff, you sometimes have another good channel to compare.
You also might have to draw the circuit.
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I got an HP200C (one of HP's 1st audio oscillators) for free.
https://hpmemoryproject.org/wa_pages/wall_a_page_01.htm ebay price is like $500.00 USD.
Later, I got one of these:
https://www.amazon.com/Tenma-72-505-Hand-Audio-Generator/dp/B008DJS2GY
because I was servicing audio amplifiers. I do have a full 20 MHz function generator, the PM5139:
**broken link removed**
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