Lg MB EBU60674845

[Dowhile]

Hi guys i'm trying to repair this mb, i have the red led standby and no power by pressing any button. Psu is ok, Tv Model is 42LH5000

I m trying to understand which voltages to check on IC. In the service manual i have +3.3V and +3.3V_ST power lines. I have also others +3.3V power lines but i dont understand which IC are powered during the standby and which is the one responsible to receive the power on command.
For example during standby i dont see the +3.3V on the graphics cpu IC100
LGE3369A on the R229 Resistor but i think it's normal coz +3.3V power line is off in standby mode right?

Sorry for my english!

[Diah]

Re: Lg MB EBU60674845

first of all it was nice if you upload over here photo on the MB and the service manual to let user follow it with you..

but as blind answer from my memories on this MB.. IC100 are the main cpu... it should had beside it eeprom IC with 8 pins i guess on lg will be most of time IC103
3.3V_ST are first key voltage will be found on the IC103 withhin the firmware script on it will sent command to IC100 to tell i am ready... ic100 will send 3.3V to power boards ( PWR_ON. so the PWB will turn on and send the rest V such 12 & 24V etc.

if 3.3ST found on MB.. and when press any key opn RC or at set panel no reaction on led indicator it sound the eeprom ( or it flash FW) silent no command sent to IC100

[Dowhile]

Re: Lg MB EBU60674845

first of all it was nice if you upload over here photo on the MB and the service manual to let user follow it with you..

Thx for answer , this is the manual


IC100 is the main you re right, ic103 is the flash for the boot. in the datasheet eeprom receive +3.3V not 3.3V_ST indeed i dont see voltage betwenn its GND and VCC.

Pls can i ask you where to check for the correct voltage on the IC100 during standby? I measure 1.9V on R229 i think it should be 3.3V right?

From IC 801 +3.3v_ST voltage is right then this voltage across r195 resistor and drops to 1.9V.

I measured KEY1, signal drops to 0V when power on button is pressed so the ic100 is receiving the signal but nothing change. EEPROM stays at 0Volts. so ic100 is not working right?

[Diah]

Re: Lg MB EBU60674845

trace voltage on MB specially on IC100 impossible because its SMT part.
we follow V on MB only if we have issue for example no sound. or no key at panel ..etc
we have SPI flash ( boot ) and main IC. and some time the IR boards need to check..
Only Red LED status with no reaction will be only this three parts responsible.

[Dowhile]

Re: Lg MB EBU60674845

diagrams dont help in order to find vdd of the ic100?