LG NB4530A , stays in standby/wont turn on.

[Moreno83]

Hi guys ,

Purchased a defective LG 35mm ultra slim soundbar which i want to repair.
The only thing it does is giving me a red standby light when the mains is plugged in.
I dont have the remote but the touch buttons on top won't turn on the soundbar , the LCD stays black!

It uses a 25v/2A powersupply which measured good. I opened up the soundbar and there is not much inside. Just 1 big mainboard and a few small boards with hdmi/bluetooth etc.
The 2 fuses are ok and there is no visible damage on the board.

I could not find any service manual for this soundbar and what you see on the pictures is what is inside. ( no big power supply , just caps... ).

Anyone got experience with these soundbars?


My first guess is to start replacing the capacitors and see if it changes anything. On picture 6 is a IC701 that has a heatpad on it.... not sure what it does but that would be my second guess....


thanks!

[Moreno83]

Re: LG NB4530A , stays in standby/wont turn on.

I looked up the part IC701 and it is TAS5612LA which is a 125 W Stereo/250W Mono HD Digital-Input Power Stage.

[Moreno83]

Re: LG NB4530A , stays in standby/wont turn on.

I found a repair manual for a similar model ( 5530 ).



I will follow that repair manual and replace the components. Will let you know the outcome.

[Moreno83]

Re: LG NB4530A , stays in standby/wont turn on.

I am having a hard time repairing this soundbar because i don't have the correct service manual. The service manual listed is for a later model. Looks almost the same but im missing a few components.

Following the service manual i replaced 2 dc dc converters ( TPS54231D/TPS54233 ) and a schottky diode but im pretty sure im not getting the right voltages. I got 25v going in IC608 and 5.5v out....i think it has to be 12v going eventually to the amp section. ( IC701 )

Even after replacing the part i get the same voltages. Also in the IC701 section i get 25V in but there is no voltage going to the schottky diode. SM says i need to replace the diode if i don't get voltages. I replaced it but still same issue.

I got a feeling the MICOM is dead.

I had the luck that i found a replacement board on a polish site so i wil go for that and will order the MICOM cpu and see if it will fix my issue.

Will keep you posted.

[budm]

Re: LG NB4530A , stays in standby/wont turn on.

If you look at the spec sheet of the TPS54231D/TPS54233, you will see that the resistor network connected to the VSNS determine what the output Voltage should be, see page 15 of the spec sheet so look at the value of resistors and use the formula to calculate the output Voltage.

[Moreno83]

Re: LG NB4530A , stays in standby/wont turn on.

Thanks! Will check the value of both resistors and do the math.

[Moreno83]

Re: LG NB4530A , stays in standby/wont turn on.

So i got a replacement board from a polish site.
The soundbar turns on , display turns on but nothing comes on the display. Just blanco lcd.

It only responds to the power button ( on/off ) and no sound coming from the soundbar.

Have to take a deeper look into this soundbar.