My avr 300 is making a humming sound through all speakers. It seems to be a little worse on the directv input but humming all the time. Is there a fix or a common problem that I am missing??
Audio Players & Recorders - Harman Kardon - AVR 300 Receiver
Answers & Comments
Remove all the input cables and see if the speakers still hum. If they do you have a problem in the amplifier, probably a bad capacitor. Remove the power and open the unit by removing the case. Should be screws on the back and side. Find where the power cord comes in and follow it to the board. This is the power supply section. Look at all the different sized cylinders (electrolytic capacitors) in that area for bulging. Replace any which look suspicious. Also inspect all the electrolytics throughout the unit for bulging, replacing as necessary. If this does not solve the problem you will probably need to take it to a tech for repair. If the unit quits humming after removing all the inputs you have a cable or cables with a broken ground. Get a known good cable, preferably new, and check the unit. If it still works OK, replace each input until the hum comes back. That will be the bad cable. Toss it and keep going until you get all the bad cables weeded out. Let me know if you need anymore help.
hardrocko
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No, nothing in the house would do this. It is internal to the
amp. You have a failed component in the set. Just because no capacitors are bulging does not mean they are OK. It's just easier to find them when they bulge. If you hook up a dvd and still have hum you will need to replace all the capacitors in the power supply. If that does not solve the problem then you will need to replace all the capacitors in the rest of the unit. Parts can be found at