Lg423000

[domix]

Re: Lg423000

Any ideas what to do to make tv work again

[budm]

Re: Lg423000

Okey, now i read dc voltages
on Inverter
24V - 14.5V
on/off - 4.6V
error - 0V
pwr on - 2.1V

and on P201
pwr_dim - 2.1V
on/off - 4.7V
5V - 5.14V
12V - .941V
16.5V - -0.02V

OK, disconnect the cable between the power supply board and the inverter board to see if you will get the 24V/12V/16VDC back, these 3 Voltages are generated the same power transformer T102.

[budm]

Re: Lg423000

BTW, that White Fuse F101 T 3.15A 250V in the middle of the board is good, right?

[domix]

Re: Lg423000

hello, i measuser it
whit cable connected is:
5V- 5.12V
12V- .967V
16.5V- -04.7mV

cable disconnected
5V - 5.12V
12v - .970V
16.5V - -08.4mV

and both of two fuse are good

[domix]

Re: Lg423000

Anybody can help me, i dont want to trow it away.

[domix]

Re: Lg423000

now i measured one more time, and i tourn tv on measured, turn tv off, and turn on once again and tv work perfect, like it has to be. then i turn off and turn on one more time and again nothing hapend only 3 red flashes nad the same story like before nothing shows up.

[domix]

Re: Lg423000

What to do? Any suggestions pleass, or i buy power board on ebay?

[domix]

Re: Lg423000

anybody? :/

[budm]

Re: Lg423000

OK, we need to check the dcV between the two legs of the main filter cap in the hot side of the circuit to make sure we do have PFC Boosted Voltage of around 400V when power switch is activated, you must be real careful not to touch anything on the board with your hands or body and do not let the probes slip on you while making the measurement.

[domix]

Re: Lg423000

i get only 331V on main 450WV 150uF cap :/

[budm]

Re: Lg423000

i get only 331V on main 450WV 150uF cap :/

So the PS-ON (PWR_ON) is present and the STBY power supply is working but you still do not have the boosted Voltage on the main filter cap so you will need to get the P/N of the PFC Controller IC to find out which pin is the VCC pin and find out if VCC is present or not.
The 12V/24V SMPS requires that boosted Voltage to run.
BTW, you did check the Voltage on the cap when the TV is turned on, right?

[domix]

Re: Lg423000

Yes, tv was pluged in and turned on. Can you give me more detailed steps where to check this

[budm]

Re: Lg423000

I will have to study board to locate the PFC IC, it will be later on this afternoon.

[domix]

Re: Lg423000

Thanks

[budm]

Re: Lg423000

I took a quick look at https://www.badcaps.net/forum/attach...9&d=1456934878

It is U601 16-PIN SMD IC close to the bridge rectifier.

[domix]

Re: Lg423000

Okey i got it. Which pin i must measured, can you help me whit some steps

[budm]

Re: Lg423000

We need the P/N as printed on top of the IC so we can look up the spec sheet to get the pin out of the IC.

[domix]

Re: Lg423000

on this U601 chip is the number 87ACD7M UCC28060 G4

[vinceroger69]

Re: Lg423000

link too data sheet
http://pdf1.alldatasheet.com/datashe.../UCC28060.html

[domix]

Re: Lg423000

i measuer both current with tv on on this VCC pin and get on multimeter AC (V~) 36.8V and DC -49.8V ( didn't know whic must i measured