Standby light only LG LG42LB5500

[StephenU]

Picked this unit up cheap and thought it would be an easy repair, (Panel looks fine and undamaged) unsure of history only going on the words of the seller. Seller says he had a power cut and the TV never came out of standby after that.
So, the TV powers onto standby only and will go no further my first thoughts the Mainboard has become corrupt, just wondering if anyone has any advice to throw out there. Will add better pics ASAP, but the Mainboard, PSU and Panel numbers are as follows:



MB
MZM4526-64029 MT EBT62973012
LD44B EAX65361503 (1.0)


DISPLAY
LC420DUE (FG)(A6)


PSU
EAX65423701 (2.0)
LGP3942-14PL1

Thanks in advance.

[vinceroger69]

Re: Standby light only LG LG42LB5500

maybe you can dissconnect the mainboard and test the voltages are all there ie 12v and 24v etc that way it will rule out a bad psu

[ReeceyBurger123]

Re: Standby light only LG LG42LB5500

To test Psu unplug Mb and it turns on then test voltages let us know.

[StephenU]

Re: Standby light only LG LG42LB5500

Thanks guys, much appreciated. will let you know the outcome.

[Andrew F. Ali]

Re: Standby light only LG LG42LB5500

You have a Main Bd issue......Replace the Main Bd.....that will solve your problem.

[StephenU]

Re: Standby light only LG LG42LB5500

When plugged in and checked output from psu I only get the 3.5v, no 12v or 24v

[ReeceyBurger123]

Re: Standby light only LG LG42LB5500

It might require you to force it on normally they dont on these Lg Leds, do what Vince says.

[budm]

Re: Standby light only LG LG42LB5500

if there is no PS-ON signal from the main board to turn on the power supply/LED driver board then there will be no switched 12V/24V.

[ReeceyBurger123]

Re: Standby light only LG LG42LB5500

Hang on bud Ive had this same set thinking about it Led fault but I thought it was in standby but unplugging the Mb would bring the Smp up. But could be different also shown in a video of mine.

[StephenU]

Re: Standby light only LG LG42LB5500

if there is no PS-ON signal from the main board to turn on the power supply/LED driver board then there will be no switched 12V/24V.

Hi budm I've shorted the PWR-ON to 3.5v rail on the connecter of the PSU and the PSU gave me the 12v and 24v. I'm thinking mainboard issue.??


Thanks

[budm]

Re: Standby light only LG LG42LB5500

If you can force on the power supply then the power supply is OK.
You should report the DCV reading of the pins of the connector of the power supply board that goes to the main board, make sure to give the pin names and floow by the DCV reading so we can see what are missing.

[Andrew F. Ali]

Re: Standby light only LG LG42LB5500

you have a main bd issue......replace the main bd.....that will solve your problem.

+1

[ReeceyBurger123]

Re: Standby light only LG LG42LB5500

+1

Lol plus 1 your own comment, also I agree replace mb. But he could try a new flash Ic or reflowing it.

[Andrew F. Ali]

Re: Standby light only LG LG42LB5500

lol plus 1 your own comment, also i agree replace mb. But he could try a new flash ic or reflowing it.

[Diah]

Re: Standby light only LG LG42LB5500

why do you have Oven at home ??

use it for this MB , low coast just little smell at backing 10 minute 220 degree

[ReeceyBurger123]

Re: Standby light only LG LG42LB5500

Oven is for food not pcbs.

[StephenU]

Re: Standby light only LG LG42LB5500

Thanks to all for there input and help, managed to pick up a new MB and problem solved.

[ReeceyBurger123]

Re: Standby light only LG LG42LB5500

Awesome, also turn the backlight down and add a heatsink to that cpu !

[StephenU]

Re: Standby light only LG LG42LB5500

Awesome, also turn the backlight down and add a heatsink to that cpu !

Done, thanks again.

[ReeceyBurger123]

Re: Standby light only LG LG42LB5500

Awesome work