TV Schematic

TV SMPS Board Repair - Can a Bad Octocoupler cause a Buzzing Sound from an In-Repair SMPS Board?

I'm in the process of repairing the SMPS board of a LCD TV and I hear an annoying buzzing sound after the transformer is turned on. Can this be because of the optocoupler?

Public Comments

1. Bad optocouplers are one of the reasons this can happen. Usually (for me) the buzzing noise was because of leaky capacitors and bad filter caps on the input side. Loose parts on the transformer can also cause this noise due to vibration interference with the transformer's magnetic field.