LG 1919s no power

[tom66]

Re: LG 1919s no power

U201 is a three-terminal adjustable shunt regulator, it's near D202 and all 1000uF caps

This sound is occuring 2-3 times in a second, but when I have powered up LCD and saw OSD, it was a continous sound.

I'm just looking at datasheet of FAN7601..but voltage on Vcc pin is 9-9.5V, startup voltage havent mesured right now, but if I remember right, it was 11V.

Sounds normal for the supply. If you have a 10 ohm 5W resistor, try attaching it to the 5V output and seeing if the tone changes considerably. Also, does the tone change with no monitor connected when the power board is unplugged - does it increase in frequency near the end?

This sounds a lot like the power supply doesn't like having no load. Many are like that; they require a minimum load to maintain the Vcc voltage. Older computer power supplies are like that, too.

[tom66]

Re: LG 1919s no power

U201 - is that a TL431?

[swen_blueneon]

Re: LG 1919s no power

Recaped with some Chemicon and some Rubycon and still got the same issue..

Really don't know what else to do?!

[swen_blueneon]

Re: LG 1919s no power

U201 - is that a TL431?

yes, it is TL431 (K1A 431A 628)

BTW tried with 10Ohm 10W resistor and everything is the same.
The noise didn't change even if I connect monitor and CCFLs..just ''crc crc....''

[swen_blueneon]

Re: LG 1919s no power

Guys thanks for the help...especially to tom66

I think I'll buy new one, cause this is way to much or damaged or just one stupid thing but I can't figure out what...

TNX
p.s. see U on the forum

[muji]

Re: LG 1919s no power

when i plug from board to lcd cable my power supply voltages unstable withouth that inverter working plz help me