Haier LE42F2280 Blue power light dead otherwise

[ny_jets_head]

When pressing the power button nothing changes the set does not turn on, no back light is visible. Cant seem to find a manual for this one online if someone has a link to one or some suggestion as to what to check on this unit it would be appreciated.

[vinceroger69]

Re: Haier LE42F2280 Blue power light dead otherwise

can you post a piture up of all boards in the set so we can see what psu etc the set uses then we can advise on tests etc.

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

Here ya go.
I may have cut off the T-con board if that is needed I can post it.
Ignore the crack on the end of the PS board it is not an issue.

[vinceroger69]

Re: Haier LE42F2280 Blue power light dead otherwise

can you remove the psu and post a picture of the back up just so we ourselves can see if any traces have been broken around that crack area also we can also see what components are on the uderside of the psu thanks

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

I checked it, no traces are broken, but I can post a picture if it helps.
I should probably fill in my profile.

[vinceroger69]

Re: Haier LE42F2280 Blue power light dead otherwise

if you could post a pic so we can see the parts on the bottom of the psu cheers

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

Rear of board attached.

I measured the voltages on CON201 based on the etching from top to bottom
Actual Etching
13.6 12V
13.6 12V
0 G
0 G
0 G
5.3 5V
5.3 5V
5.3 5v/SB
4.9 PON
0 BK/ ON TP7
2.3 ADJ
0 G TP2


The LED assumed to back light had no voltage as expected they are not on.

PON did not toggle when I pressed the button

[euclio]

Re: Haier LE42F2280 Blue power light dead otherwise

Same model, same symptoms. Did you find the root cause? I'm going to start troubleshooting/testing components this week-end.

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

Nothing new... I am facing the same situation just haven't had the time.

Please share anything you might find out.

[euclio]

Re: Haier LE42F2280 Blue power light dead otherwise

Thanks for posting back. I will definitely reply if I figure anything out.

[budm]

Re: Haier LE42F2280 Blue power light dead otherwise

"0 BK/ ON TP7" You are not getting Backlights on signal from the main board, this pin should be >2.5V or so.

4.9 PON = PS_ON (MAIN POWER SUPPLY ON) signal from main board
0 BK/ ON TP7 = Backlights ON signal from main board
2.3 ADJ = Backlights Dimming control signal from main board
0 G TP2 = Circuit ground.

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

"0 BK/ ON TP7" You are not getting Backlights on signal from the main board, this pin should be >2.5V or so.

4.9 PON = PS_ON (MAIN POWER SUPPLY ON) signal from main board
0 BK/ ON TP7 = Backlights ON signal from main board
2.3 ADJ = Backlights Dimming control signal from main board
0 G TP2 = Circuit ground.

Thanks.

I looked over the board and without a print I have to assume I need to get a main board to make it work.

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

Is 13.6V A good voltage for the 12V here?

I checked over the voltages on the mainboard I have the same 13.6 , 5 V and 3.3V which is derived on the mainboard.

All fuses test OK.

[budm]

Re: Haier LE42F2280 Blue power light dead otherwise

The 12V which is used for the audio power amplifiers to drive the speakers, this voltage is not tightly regulated since power amp does not need tightly regulated power supply to run.
What you can do to see if you can get the backlights to come on is to disconnect the BK ON wire from the power supply board and use 500~1000 Ohms resistor between the BKON pin on the power supply and the 5V pin, if there is nothing else wrong with the main board, then you should see pictures on the screen and all other functions should be working, then we will know that you just have one problem with the BKON drive signal.

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

The 12V which is used for the audio power amplifiers to drive the speakers, this voltage is not tightly regulated since power amp does not need tightly regulated power supply to run.
What you can do to see if you can get the backlights to come on is to disconnect the BK ON wire from the power supply board and use 500~1000 Ohms resistor between the BKON pin on the power supply and the 5V pin, if there is nothing else wrong with the main board, then you should see pictures on the screen and all other functions should be working, then we will know that you just have one problem with the BKON drive signal.

Thanks

I was thinking that also... to force the backlight on and see what I have.
I'll give that a go next

Edit:
Back light comes on nothing displays on the panel.
I checked the VCC to the Tcom and found 0V,
Checked with the cable disconnected from the Tcon and found 10V regressing to 0V
The VCC comes from a chip regulator ( I assume ) X7NV ( with 1X going vertically) on the device case.
I measure 13.6 on the over legs and the center tab goes to Panel VCC

Any idea what this chip is and where I can get a data sheet to confirm its operation? I goggled it and didn't get a hit on a chip

[budm]

Re: Haier LE42F2280 Blue power light dead otherwise

I am not sure if that device is the 12V LCD panel switched MOSFET that is turn on by the main board, so at this point your main board is bad.
Post the pictures around the LVDS cable connector, there should be MOSFET close by.

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

The mainboard reacts to the power button and turns on.
The back light flashes and goes dark until I press the power button then it turns on. This of course is with my jumping the back light on to 5V

Should have added that the source of the TCON Vcc is the mainboard
This device is adjacent to the socket for the TCON cable

The chip in question is the one at the far right

[budm]

Re: Haier LE42F2280 Blue power light dead otherwise

"Should have added that the source of the TCON Vcc is the mainboard" Yes, that is why I indicated that there should be switched MOSFET close by the LVDS connector, this MOSFET gets its 12Vdc from the power supply. What Dc voltage do you at those two 3-pin device when the TV is OFF and when the TV is ON?
Looking at the device with the one leg on top.
Pin 1 (left leg) = xxxV (TV OFF), XXXV (TV ON)
Pin 2 (top pin) = xxxxv (TV OFF), XXXV (TV ON)
Pin 3 (Right pin) = xxxxV (TV OFF), XXXV (TV ON)
I will not be surprise if the MOSEFT is not getting the turn on signal from the processor either.

[ny_jets_head]

Re: Haier LE42F2280 Blue power light dead otherwise

Left most in picture
Pin 1 (left leg) = 0V (TV OFF), .09V (TV ON)
Pin 2 (top pin) = 0v (TV OFF), 13.6V (TV ON)
Pin 3 (Right pin)= 0V (TV OFF), 0V (TV ON)

Right most most in picture
Pin 1 (left leg) = 0.01V (TV OFF), 13.4V (TV ON)
Pin 2 (top pin) = 0.01v (TV OFF), 0V (TV ON) VCC to Tcon
Pin 3 (Right pin) = 0V (TV OFF), 13.6V (TV ON)

[budm]

Re: Haier LE42F2280 Blue power light dead otherwise

"Right most most in picture
Pin 1 (left leg) = 0.01V (TV OFF), 13.4V (TV ON)
Pin 2 (top pin) = 0.01v (TV OFF), 0V (TV ON) VCC to Tcon
Pin 3 (Right pin) = 0V (TV OFF), 13.6V (TV ON)"
OK, for quick test, you can jump Source and Drain and see if you do get pictures on the screen.