My tv humm - Coby 40 TFTV4028 LCD TV

Bad scart connection or need new stronger scart lead

First of all, it is bad form and potentially dangerous to be changing cables with speaker power ON. Second, IS the unidentified TV passing audio out those jacks? Its own audio menu and controls may be between the sound and the jacks.

You´d better use a power conditioner, such as Panamax. Besides, it will protect the system against power surges and will eliminate the humm.

Im talking about general troubleshooting here. Usually with this size of motor 1Hp. Check if it have a capacitor, commonly if this humms the capacitor is faulty. It is a capacitor start motor. Another fault could be stuck up. Or one of the winding has a short. Hope it helps

You have a bad ground through the cable box or cable system. This causes AC to leak into the TV showing up as bars that roll from bottom to top and sometimes audible as well. Have the cable company replace the cable box and/or check out for proper grounding outside at the demarcation point.

Need to listen for fuel pump humm for proper operation. Shoud humm for about 3 seconds with key turned in the on position. Humm will sound from gas tank where the pump is located. If it does not humm. possible Faulty Fuel pump relay or pump. It will need ferther diagnosis.

A humm may be caused by a cable TV grounding problem called a "ground loop." Basically, the grounding for the Cable TV line and the power outlet for the TV are at unequal levels. I had this same humm with both the internal TV speakers and with external speakers (headphones, etc.). The 2 solutions are (1) install a Ground Loop Isolator at the TV, or (2) call the cable company to troubleshoot the problem. I figured the time I saved dealing with the cable company was worth the $50 for the part. I installed the Jensen VRD-1FF which has worked perfectly! Ordered from eBay and saved about $12 over the Jensen Electronics web site price. Hope this helps.

The "HUMM" indicates a breakdown in the High Voltage Side. The loud "POP" was the breakdown. You have only four Components in the High Voltage side.

1. High Voltage Transformer. You can eliminate this as the problem. Why? If it was the problem it would have blown the line fuse, and would have given off a burned transformer smell.
2. High Voltage Diode. Usually will Burn or Pop when shorted, but will then OPEN the Circuit and there is no "HUMM".
3. High Voltage Capacitor.This is the Silver Can with the two terminals on top. It can SHORT internaly between the plates (the two terminals) and give the "HUMM".
4. Magnetron. This is my number one suspect. A SHORTED Magnetron.

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