As the goo leaks out of an electrolytic cap, the capacitance drifts so far off spec that the circuit will stop working as intended. In guitar amps, filter caps that are drying out make the amp noisy because they are no longer able to filter out the current ripple from the AC power source.
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Great video, thanks! With ‘wet’ type caps, eg electrolytic, the electrolyte goo greatly increases the permitivity between the cap’s plates. If it leaks out, the greatly reduced permitivity means it can’t hold as much charge, hence its capacitance value is greatly reduced. Also its parasitic characteristic of ‘equivalent series resistance’ increases. Basically, if goo leaks, the cap may as well not be there and as the great ‘goo says, the circuit almost certainly won’t work as it’s supposed to. Due to the uses ecaps are usually put to in amps, such a fault often won’t cause a fuse to blow. An exception being the reservoir cap for a fixed bias supply. The job of the reservoir cap is to fill in the gaps between the rectified pulses of ac (ie act as a reservoir). That actually increases the average Vdc of the supply. If the goo leaks then cap stops filling in the gaps, the Vdc of the bias supply will reduce and the power tubes will run hotter; but probably not draw enough current to blow a fuse. But the power transformer has to deliver the extra current that the power tubes are continuously drawing, and when that gets enough above the rating of the HT winding, the winding will overheat and fail, power transformer ruined! Because the HT current in that scenario isn’t much above the normal peak loading, it’s very difficult to protect the winding from such a fault with a fuse, even a dedicated HT fuse. So, good caps in the bias supply are ‘mission critical’!
I wished when I was in college I had him my 1st semester of Basic Electricity. That guy is a hoot!
Reminds me of my first lab on transistor circuits they teamed us in two to do the experiments. Well I got paired with the most brilliant guy in the class. He was hooking up a transistor in a circuit and I told him I think you have it backward. He would not listen and basically poofed me off. Should have seen the expression on his face when he turned the power on and the transistor launched itself from its "Launch pad" and hit the guy right in the forehead. Cool stream of smoke and the Transistor leads remained in the circuit.