I'm troubleshooting one of my oscilloscopes which has lost its trace. Since the PSU seems OK and the front panel LEDs still light, the buttons still switch the relays etc, I'm guessing it's in the CRT section.
I have begun performing visual inspections, and while looking around the neck board I noticed a trimpot which seems to have started growing white crystals - out of the plastic!
I also noticed these to a lesser extent, on the main power switch body and the case of what seems to be some part (as yet unidentified) in the mains filtering circuit.
Has anyone seen anything like this before? I assume it's some breakdown of the plastic due to contamination or incorrect manufacture. I don't think it's environmental, only those three parts seem affected. Another trimpot on the neck-board looks totally normal.
Interestingly enough, this crystallised trimpot is part of a circuit which seems(?) associated with the cathode voltage (the schematic is labelled in French) - so maybe it has failed and is the cause of the fault?
I have begun performing visual inspections, and while looking around the neck board I noticed a trimpot which seems to have started growing white crystals - out of the plastic!
I also noticed these to a lesser extent, on the main power switch body and the case of what seems to be some part (as yet unidentified) in the mains filtering circuit.
Has anyone seen anything like this before? I assume it's some breakdown of the plastic due to contamination or incorrect manufacture. I don't think it's environmental, only those three parts seem affected. Another trimpot on the neck-board looks totally normal.
Interestingly enough, this crystallised trimpot is part of a circuit which seems(?) associated with the cathode voltage (the schematic is labelled in French) - so maybe it has failed and is the cause of the fault?
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