Panasonic Th-42A400z led tv

[vinceroger69]

Re: Panasonic Th-42A400z led tv

what are you trying too find on your tv the led strips? if so you need to remove the lcd panel and the various sheets under the lcd but keep these dust free and in order this video may help
https://www.youtube.com/watch?v=5rwLDxKgZIA&t=12s

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Ok so i have found these 2 boards are available but the question is are they replaceable?

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

ok so today i tried the boards from my dead tv in the good tv and they all work so im left with it being the panel..Im guessing the 2 boards at the bottom of the panel are attached and not replaceable? Is this whats meant by the panel. I did test the led in the good tv and have the same reading as the bad one which rules out the leds right?
well if no other options i guess i have a few spare boards..

[aanan]

Re: Panasonic Th-42A400z led tv

Littel help

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Tread carefully. Nothing worse than annoying the wife

Yes or ending up with 2tvs that dont go lol

[dick_barton]

Re: Panasonic Th-42A400z led tv

Hi yeah i did try following the test diagrams and my voltage tests point to a faulty LD board but trying to source one of these isnt proving the easiest well i found the boards but i dont want to pay around $70 shipping. I have another tv exact same model working so i might try the board from that before i pull the screen apart or order a board..i just have to wait for the missus to go away so she dosent have a fit lol.

Tread carefully. Nothing worse than annoying the wife

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Pages 67 & 68 may be of help to you.

Hi yeah i did try following the test diagrams and my voltage tests point to a faulty LD board but trying to source one of these isnt proving the easiest well i found the boards but i dont want to pay around $70 shipping. I have another tv exact same model working so i might try the board from that before i pull the screen apart or order a board..i just have to wait for the missus to go away so she dosent have a fit lol.

[dick_barton]

Re: Panasonic Th-42A400z led tv

Pages 67 & 68 may be of help to you.

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

ok looks like i had the wrong wire pairs so i managed to test the 2 correct pairs of wires in the dark and could see the glow through the back panel the first pair reads 43.9v and the second pair 65.5v is this likely to be bad leds...

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Yes i used the diagram from the test manual from earlier in this post to determine which were the right pairs of wires so i figured it was the 2 outside orange and black and 2 inside red and brown i did try red black and orange brown also but same result.

[budm]

Re: Panasonic Th-42A400z led tv

So you disconnect the LED connector from the power supply board and correctly connected the LED tester Red and Black probe to the correct LED + and LED - of the LED's connector?

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Hi guys im back, I got myself an led tester and plugged it into both sets of leds but the voltage stayed at 326v on both of them which is what it sits on when just the power is plugged into the tester. So im not sure what this means next..does this mean they are good or bad or bad test..any suggestions appreciated.
thanks.

[budm]

Re: Panasonic Th-42A400z led tv

You can test the LED strip without disassemble the screen, you have two sets of LED strings, that is why you have 4 wires, so you will remove the LED connector from the LED driver board and then test each pair with the LED tester. The Tester has Volt meter that will show the total Vf (forward Voltage) of the LED string, so you just have to compare the two readings.
Example of using LED tester to find out the condition of the LED string, as you can see, his reading was only 130V so he has some shorted out LEDs. The screen did light up for second but it went into shut down due to shorted LEDs.
https://www.badcaps.net/forum/showthread.php?t=70274

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Hi Guys thanks for all your suggestions so far so ive got to the point where i need to test the led strips. One of those led testers is about $50 if i buy from ebay or over $100 local,my question is do i still need to pull the screen apart to test the strips or can i test them somehow without spending lots, i do understand if its a strip i need to pull the screen apart anyway.
Im just looking for an easyish solution.
Unfortunately or fortunately i guess im booked in to have eye surgery for glaucoma on the 4th July so wont be a lot happening with the tv for a while anyway.
I will be keeping an eye on the forum and let you all know when im back into it.
cheers
Nick

[yohnsee]

Re: Panasonic Th-42A400z led tv

Don't know how close this manual is to your set but may be useful.

It was sure useful for me, thanks.

[R_J]

Re: Panasonic Th-42A400z led tv

That tells me that one of the two led strings is loading that side of the Ld power supply,
an led tester with current readout would likely confirm it.

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Hi I tested both C7813 and C7817 with the LD2 plug removed and yeah the voltages did jump up to close to each other.
Nick

[R_J]

Re: Panasonic Th-42A400z led tv

If you disconnect the LD2 plug going to the panel and check the voltage across C7813 is it still low, or does it come closer to C7817
Needs to be measured while turning on tv as it will error and drop down

[lambchopsnz]

Re: Panasonic Th-42A400z led tv

Ok it turns out you cant edit posts even though it says edit it wants to create a new reply so here are the pictures the way i first intended on uploading them i hope...