Hello, i am losing my will to live but perhaps you might be my saviour in shinning armour.
i have a PM-3 that mic input 9 and 10 is not working. (line input is fine). i traced the fault and suspect one of the transistors in the pre-amp stage is corrupting (but in the two channels you ask), well i thought so too, but the op-amp is not the culprit and yes i can see the input signal on scope but gets lost thru the array of NPN and PNP pre amp transitors, thus no input signal to the op-amp.
i cannot identify these transistors without the aid of a picture from the schematic.
is this something you might be able to help with?
look forward to hearing from you.
Comments
Hi,
problem you described is very common on this model. Problem is, no SM xxxx-3, and is much different from xxxx without -3. But I solved few of this model with same problem with BC846-856 NPN-PNP pair. But you must finde on nearby OK channel where is the NPN i where is PNP position .It is quit tricky to find a bad transistor onboard without component tester because the faulty part is not in short between BCE.
best regards
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