Loud buzzing noise when I turn amp on -won't go away

You have two options. First a faulty cartridge. Or a faulty pre-amp in the main amp.
You can find out if the cartridge (and amp) are playing up. By removing the connectors on the cartridge.
Then with the volume turned up to about half, with your finger, touch each one of the wires one at a time. It will not harm you at all. But you should hear a loud buzz on one wire on the right and a loud buzz on the left on another wire.
The two other wires will either produce a crackle, or a tiny buzz, or nothing at all.
If you do hear a loud buzz on two wires. The cartridge is faulty and needs replacing.
If you hear a slight buzz on them or weak sound. There is either a bad connection between the deck and amp. Or the pre-amp inside the deck which is only used by the record deck so will not effect any other function, is faulty.
You can remove the record deck connections to the amp and again with the amp on half full, touch the inputs with your finger. If you are not hearing a loud hum or buzz, the pre-amp is faulty. If you do the connectors are faulty.

may be you have a ground wire loose

Buzzing is usally AC line noise leaking into an un-shielded cable somewhere or a floating ground. If the AC plug is reversable, try that. make sure all audio cables are pluh\gged in tightly at each end and routed away from or at right angles to any power cords and away from other sources of strong magnetic fields like TV's. I've also seen variable track lights induce noise but it's usually minor.

If it still does it with no cables attached it's an internal amp problem.

It sound like you may have sound processor problem which is part of the main board, I would also look at the 12vdc from power supply to make sure it is clean DC.
Parts: http://www.shopjimmy.com/catalogsearch/result/?q=l37hdtv10a

http://en.wikipedia.org/wiki/Capacitor_plague

Color wheel needs replacement

Buzzing noise - contactor. maybe a bug got in the contacts or maybe the coil is bad but in any case if you replace the contactor the buzz will go away.

Watching tv all of a sudden loud buzz noise,I shut off unit turned back on loud buzz came back about 30 seconds later loud pop pop then smoke came out of top of unit, i'm not please as this unit i bought about 17 months ago @ Canadian Tire Belleville & warranty is now not covered, pobably will never buy another Proscan product but am more concerned there could be a fire caused buy this than getting unit replaced

Check all your wires and make sure that none of the wires that are powering any equipment (including extension cords, power bars, and power cables on the unit itself) are running parallel to any of the audio cables going to your speakers or from your inputs to your unit. This could be what's called AC hum, which is caused when the electrical current causes interference that gets picked up by the audio cables and amplified by your system. Just make sure you move the power cords as far away as possible from the audio cables.

I have the same problem I can hear buzzing over the volume of the tv into the 30 range. I've had a tech out 3 times and he's coming out for a fourth. He's changed to power supplies and is bringing the 3rd next visit. From what I've read it has either to do with power supplies or grounding strips.

Is the buzzing coming from the back of the TV, staying loud even when the volume is turned all the way down, or is it coming from the speakers?