I have a magnavox 37mf331d/37 that has developed a high pitched whine.the longer the tv is on the louder the whine.the tv is 5-6 yrs old

SOURCE: High pitched noise

I am about to post a in depth guide about how to fix this problem. It's because a capacitor inside the TV has blown which causes the buzzing high pitched noise. It's really easy to fix however and only costs about £1 / $2 to sort out.

You can read a similar guide here http://www.fixya.com/support/r741402-polaroid_flm_373b_lcd_tv_black_screen but I will shortly be uploading a guide on the buzzing problem!

SOURCE: Philips Magnavox 37" LCD Flat Screen 37MF331D \37

There are two capacitors in the internal power supply regulator board that have been the main culprit of this particular issue. You can identify the bads ones by the slight buldge at the top of the capacitors.

SOURCE: High pitch noise coming from the tv.

I suspect you have a bad set of capacitors in the control module. This problem usually starts out as a high pitched noise but can lead to the TV not turning on. Please see the link below, posted by StivO. It gives step by step instructions on how to replace the capacitors. This is a very inexpensive fix.

http://www.fixya.com/support/r741402-polaroid_flm_373b_lcd_tv_black_screen

SOURCE: Philips Magnavox 37" LCD Flat

Disconnect the LVDS Cable that runs from the small signal board to the display panel and apply power,if the screen comes on,the Small signal board (aka Scaler Bd ) is the faulty board. other than that,all that's really left that has gone bad for me is the logic board.

SOURCE: TV MAKING A HIGH PITCH BEEP AND SHUTTING OFF AND ON

I don't know what model you have, but Sanyo tv's are designed with a shutdown after about 3 seconds, if the processor detects a problem. It sounds like the switching mosfet is not running at the right frequency. It should be above your hearing range. That tells me that you have a problem in your power supply that is causing the voltages not to come up to the proper value, and the processor is turning your tv off. If you have a schematic check the circuit around the switching mosfet, capacitors ect. I have had to replace several of their mosfet switching transistors and that was the problem. SANYO, 3333 Sanyo Rd. Forrest city Arkansas 72335 870-633-5030 or e-mail [email protected] Sanyo is releasing their maintance manuals online try searching for your maintance manual. If you have a reputable TV service center in your area the technicians should be very familar with this problem, and give you a quote before he does any work. It should be a simple fix on the power supply, (if that is the only problem) or if you have a electronic friend, he can replace the mosfet for around $9 just make sure it is the exact same part# because of the error detection in the processor, generic parts won't work. Or try www.sanyotv.com 1-800-877-5032 Their tech support has always been great to me, and I am retired and not a service technician just 45 years of prior experience. I just noticed its only 5 months old and should be under warrenty. call the 800 number and take it to the nearest service center. Hope I helped.