LG 42LV3500 trips circuit breaker

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

They were/are connected. Without mainboard does the same thing. No change if I disconnect the LED driver board either. Voltages are still pulsating.
It seems like there a slight difference with this IC, at pin #1, 3 there is a slight pulsating voltage(not sure how else to call it), goes from 0V to 0.03, or 0v to 1.3V.
Now, I have 0.4-0.5V STBY, before I had 0V.
The voltages, that I'm getting at the Vcc is seems like they are the turn on and turn off limits, 10.5V- 17.xV of the IC.

[tom66]

Re: LG 42LV3500 trips circuit breaker

Is that VCC for standby supply? Check/replace usual suspects: startup cap, secondary diode, primary diode, and finally controller IC if all else fails.

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

Is the Vcc at the standby IC(pin #7).
I have replaced the start up cap with no change and two days ago I have replaced the IC, with not much change, some slight voltage differences.
I can look at the diodes, but if I recall correctly, I have checked them already.

[tom66]

Re: LG 42LV3500 trips circuit breaker

Try and see if any other circuits borrow the standby aux power, that means main power controller, etc. Also, does it bounce up and down with main board out, and a small bulb attached to 5V STBY? (You could use a torch bulb, or you could also use a 10 ohm, 5W power resistor.)

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

With mainboard removed, still bounces up and down.
I will have to try it with a bulb.

[budm]

Re: LG 42LV3500 trips circuit breaker

I believe this board uses the AUX winding of the STBY power supply to supply the VCC for the STBY IC, and also feeds the switched transistor (this transistor is turn on when PS_ON is present) to supply the B+ for the PFC Controller IC and the 12V/24V SMPS IC.

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

It bounces with a flash light bulb too.

[tom66]

Re: LG 42LV3500 trips circuit breaker

Not much else to suggest, can't think of anything else, at least.

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

Could I apply 3.5V to the STBY pin and see what happens?

[tom66]

Re: LG 42LV3500 trips circuit breaker

Yes but I'd only expect standby power, the other rails are powered from STBY supply on primary, so the TV won't power up fully, it'll just stay stuck in standby.

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

I have noticed that the 167V it's bouncing too. It stays at that level with a slight bouncing and then it drops to 153V, then bounces back to 167V.
Could this cause the rest of the voltages to bounce?

[tom66]

Re: LG 42LV3500 trips circuit breaker

It wouldn't really affect standby but is there a clicking relay in time with it?

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

I have picked up another power supply and the TV starts up show the LG logo on the screen, then the HDMI3 input and then reboots. Does this over and over.
I didn't have time to measure anything. I have tried disconnecting the LED driver board, t-con board with no change. Unplugged the mainboard, but it did not turn on this way.
I have noticed that the main processor on the mainboard which has a heat sink, it was pretty hot.
At the moment I'm suspecting the mainboard, but I will have to measure the voltages, to know more about it.
PS it was $44 from partsstop.com

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

All the voltages are there while it's on.
If I disconnect the PWR_ON wire from the connector and I measure it, it stays constant. Main processor it's getting hot if everything it's connected, but with the PWR_ON it's not connected, but supplying the 3.5V with a power supply, the processor stays cool.
I was suspecting mainboard, but now I'm not sure.
I have read some of the other thread with the Samsung D series with the click on and then off with LED problem, and now I'm thinking that I could have the same thing?
The voltage for all four LED strips are constant 27V.
It doesn't turn on fast as his TV either, it boots up shows the LG logo, then goes to the HDMI 3 input and then reboots.
I could take the panel apart, but I would like to ask you guys, maybe you have some other ideas, before I do that.
When it turns on, I don't see a darker side, but who knows, maybe the diffuser it tricks me.
Any help would be appreciated.

[mmartell]

Re: LG 42LV3500 trips circuit breaker

Try it in a dark room see if that helps you see the strips better.

[mmartell]

Re: LG 42LV3500 trips circuit breaker

Btw I have one of those D6000 you referred to and I can say this about my model in particular. I have run the led's with one half of one side out, essentially 3/4 of available lighting and no problem for either the power supply or the led's. It might help if you can figure out the wiring to your led strips and attempt to isolate some of them and see if you still get reboots.

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

Do you mean to disconnect each strip at a time?
I'm attaching a shopjimmy picture of the LED driver board and there are four outputs at the left.
At each output there is 27V, no difference to indicate somethings is wrong.

[mmartell]

Re: LG 42LV3500 trips circuit breaker

27v might be low for each strip. How do you know it shouldn't be more ?

[tibimakai]

Re: LG 42LV3500 trips circuit breaker

At least, that what I have measured using the TV's chassy as ground.

[mmartell]

Re: LG 42LV3500 trips circuit breaker

Mine are wired in series. Can't say my voltages were ever stable but they never got up to full voltage before restarting.

Just putting it out there but I agree it should be a last resort to crack open the panel.