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Old 22nd Sep 2018, 11:36 am   #16
Techman
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Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
Default Re: Sharp SG-FR35 loud hum

So you say that the unit worked until you re-fitted the case. This rules out that you may have fitted the new capacitor the wrong way round by mistake, but re-check anyway. I think you may have done some damage to the circuit board print when you were cleaning that glue off. It's worth noting that you must be able to determine the difference between glue used to hold large components in place, (which is put there by the manufacturer to protect the circuit board connections from stress breakage) and leakage of electrolyte from a capacitor. Note that now there's no glue holding the new capacitor, there will be more stress on it's solder and print trace connections, although the new capacitor may well be smaller and lighter.

Taking note of the above, I would take a careful and close look at the electrical connections and print traces going to and from that capacitor you've just fitted. With the unit disconnected from the mains and the electrolytic discharged by the brief application of a shorting link, check the entire length of each print trace from the two connections of the capacitor to each point they terminate on the circuit board with your DVM on the lowest ohms range - obviously all readings should be close to zero ohms.

The thing with it dimming a lamp plugged into the same socket when powered on seems absolutely ridiculous to me, but stranger things and all that!
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