I have 37MF321 we replaced the capcitors and everything. However when we put the power into it. We have a Chirping Noise.

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Idler bearings are very common, they can also reduce the timing advance, reduce power in the engine

I have had alot of customers with this problem. There is another pulley called the idler pulley and alot of times its bad due to the bearing wearing out. I would replace that 1st for around $20

Serpentine belts are very durable , however they do need replacement from time to time. Chirping is caused by slippage which should NEVER happen exept when engaging air conditioner or high power items that put a load on the alternator. The belt is loose or one of the pully wheels it turns is having issues with a bearing--(its not turning freely) or the wrong belt was installed in the past.

Listen carefully where the chirp originates ie Power steering, alternator, Air cond-pump-, steady bearing or spring loaded tension wheel. If the belt looks good and feels firm and tight---the problem is one of the items listed.
Also check belt is lined up perfectly on its wheels and has not jumped over a notch or two. it visual!!

clean the scale off the other belt pulleys to eliminate the sqeak

worn out brake pads and slightly warped rotors. Most brake pads have small steel tabs that touch the rotor at a 90 degree angle when it is time for replacement. if you keep driving on the worn pads, it will stop chirping but that just means the tabs (also called wear indicators) have broken off and repair is about to get very pricey.

sounds like the bearing in the hub assembly has gone bad

If the colse buttons make a chirping noise when you push them the console should be Ok. If there is no chirping noise with the push it is a bad console. If everything but the speed works it will probably be your motor controller that is bad.

Did you check the Horizontal Output transistor to see if it were shorted, and also check the MOSFET of the switching power supply. 

Most of the time, when there is a chirping comming from a TV set, there is a short somewhere inside the TV set. That chirping noise is the TV's power supply starting up and shutting down because of a heavy load on the power supply. These sets have no user replaceable parts inside them, so play it safe, and call out a pro to assist you in this repair. good Luck PS Please do not forget to rate this thread.