LCD TV SMPS Repair - 3 Reasons For The Buzzing Transformer Noise when the SMPS is turned on

I was recently repairing a 200W SMPS board of a LCD TV where the power supply had been restored to a certain extent using some nifty schematics.

Burned power supply (blown fuse) is one of the common reasons for SMPS failure, and without the right schematics, it can be a nightmare to find the cause of the problem.

When I turned on the power I heard a buzzing sound (noise) from the transformer. It was like a high whine...an expected yet annoying sound that needed to be fixed. And the way to fix it is to first look for any visible damage across the SMPS board.

Usually, there are 3 reasons why you're hearing that buzzing sound:
1. Bad filter caps on the input side
2. Bad diodes, leaky capacitors or bad optocouplers
3. Loose parts on the transformer that vibrate because of the transformer's magnetic field.

Source Website

SMPS Repair Techniques - Complete Electronics Download Course for Engineers

LCD Monitor & TV Repair Cost – A Flat Rate For Repairs is Cheaper than an Hourly Rate

If you need to send out your LCD monitor or LCD TV for repairs, make sure you choose a flat rate over an hourly rate (specially when you have a choice).

A flat rate always works in your favor as long as the technician does a good job, while hourly rates can be a pain both to you and the repair guy.

I repair LCD monitors for a living and charge a flat fee of $75 for monitors up to 18” in size. It increases by $10 with each step up (i.e., $85 for a 19" monitor and $95 for a 20" monitor)

This includes labor & parts but excludes the cost of the LCD panel (if it needs to be replaced). Most LCD repairs come with a 90-day warranty on parts, so make sure you claim yours.

LCD Monitor, LCD TV and Plasma TV - Is It Cheaper to Repair or Replace?

Most people feel that it is cheaper to simply replace a monitor or television once it develops a fault, rather than try and repair it first.
 

That, unfortunately, is not always true.

When you're faced with a situation to repair or replace, consider the cost it took to buy a new TV (or monitor). Then approach at least 3 repair shops in your neighborhood and ask for a quoted invoice for the cost it will incur to repair your monitor or TV.

I recently repaired my 32" LCD TV for less than $300. The front screen had cracked and some of the electronic parts had to be replaced. I saved at least 30-40% by repairing instead of buying a new TV.

The difference becomes more evident when it involves something high-end like plasma televisions. It is usually far more expensive to buy a new Plasma TV than to repair it.

For more fresh insights, visit:
Plasma TV Repair | LCD TV Repair | LCD Monitor Repair