LG 32 lcd not always turning ON

[nathaniel]

Re: LG 32 lcd not always turning ON

i added a picture of what i did:

1k resistor ( rated 1/4w hope its ok) from the 5.2v to pin - inverter on/off
1k resistor from the same 5.2v to pin - power_on

with the a/c plugged in and the main board disconnected

the power_on cam up to2.9v but still no other voltage beside the 5v

am i doing it right?

the board model: EAY4050440


thank you guys

[nathaniel]

Re: LG 32 lcd not always turning ON

so... does it mean the pson voltage is correct ?
and the power board is at fault

should i replace the capacitors or there is furhter checking to do?

[newtothis]

Re: LG 32 lcd not always turning ON

With jumpers in place check one of the main caps voltage with meter set to 600VAC, Careful HOT side of board. Take note of polarity

[nathaniel]

Re: LG 32 lcd not always turning ON

just to make sure ... i'm testing the two large capacitors marked c608 and c609

and i still get 330v dc

[newtothis]

Re: LG 32 lcd not always turning ON

Do you want to repair the boards or replace them?

Your PSU is faulty BTW

[nathaniel]

Re: LG 32 lcd not always turning ON

i would like to repair it if possible
ordering a board will take 4-8 weeks with our %@@#$ post service

do you think this is a capacitor symptom or somthing more compicated?

[CapLeaker]

Re: LG 32 lcd not always turning ON

i would like to repair it if possible
ordering a board will take 4-8 weeks with our %@@#$ post service

do you think this is a capacitor symptom or somthing more compicated?

I am hoping that this is the schematic for your board

Does your board have the relay option?

[nathaniel]

Re: LG 32 lcd not always turning ON

no i don't have the relay option ...just the two jumpers instead

[CapLeaker]

Re: LG 32 lcd not always turning ON

What kind of tools do you have? Do you have an ESR meter?
Try this: Heat up or cool the board and see if it turns on. If you need heat to turn on the PSU there is a bad cap somewhere.
Check the PSon circuit and the PFC circuit. Problems in either could do that. Make sure that the PSU is working correctly before you put that main board back on.

[victor_cj]

Re: LG 32 lcd not always turning ON

Check or replace NCP1396AG and SG6961SZ and will work again.

[nathaniel]

Re: LG 32 lcd not always turning ON

update:
and an hour of heating and cooling the ps
i maneged to get it start twice ( while cooling)
i tried to freeze on area at a time with no success , only when i freeze the all board it will start. :/

victor- i don't believe ican test this components with a multimeter , can i?
if this is the case i think i would be better ordering a replacment board i'm not 100% i can properly solder such a part

[victor_cj]

Re: LG 32 lcd not always turning ON

You can test it, depends on the your level of experience. At NCP1396AG check voltage pin12 Vcc, pin11 Mlower, pin9 Slow Fault. At SG6961SZ check voltage pin8 Vcc, pin7 Gd, pin1 Inv, pin5 Zcd.

[nathaniel]

Re: LG 32 lcd not always turning ON

thank again victor
i tried testing these i started testing this time the tv was on

NCP1396AG (test dc between a pin and the chip GND - don't know if it's correct)
pin 9- 65 mV
pin 11 - 7.2V
pin 12- 14.9V

SG6961SZ
pin 5 -2.8V (and pin 6 as GND) also when i touched with only one probe at pin 5 got a little buzzing from the board.



when tring to test pin 7 i accidently touched both 7+8 the main fuse got blown...
replaced it with another one and... blow again

probably shorted somthing else :/ hopefully on the same board so i'll only need to replace this one.

having fun learning electronic repairs

i'll update when i'll get a new board so i won't waist your time.

[victor_cj]

Re: LG 32 lcd not always turning ON

Check Q601, Q602.
Another SMPS board it is best for you.

[nathaniel]

Re: LG 32 lcd not always turning ON

update:

got a replacment PS board from a local technician (didn't found the parts victor mentioned available here- so that was my only option)

just wanted to thank you all for your time - the TV WORKS AGAIN!!

THUMBS UP

[victor_cj]

Re: LG 32 lcd not always turning ON

Same EAY4050440 from 32LG2000 with PFC low, caused by R609, R610, R611, R612 620K ohms resistor.
https://www.youtube.com/watch?v=uwWdRsMAcJU

[fredaelsadany]

Re: LG 32 lcd not always turning ON

Hallo every one
please measure r613(15k)/r614(820ohm)
thanks

[Alastair E]

Re: LG 32 lcd not always turning ON

There's a number of capacitors on the Mainboard along with some tiny inductors that can cause an Intermittent Dead LG...

There's kits available showing whats needed, try googling the set model-number....

An Observation--

I notice in one of your pictures--Only Two Screws mounting the PSU.

Make Sure you fit ALL screws to ALL boards Particularly on any Plasma set--Before trying to make the set work....
Plasmas particularly can self-destruct if they have a missing earth screw....