JVC LT-65N550A LED Issue

[RooTV]

Hi everyone

I was just given this JVC LT-65N550A and the guy told me that he checked it out and it has the usual LED issue.

Black screen but a picture shows when using a torch.

I haven't had a TV this thin before and when I pulled the "lump" off the back to show all the mainboard cards etc, there was no sticker saying what type of panel it is using.

Do I need to pull the whole back off the TV? it seems to me that there may not be anything underneath it to have a sticker on?

I seem to be the lucky one that gets a lot of TV's with "hard to find" parts.

I'm not sure where to start looking for replacement LED strips unless I pull the TV totally apart. I'm trying to avoid doing that twice.

Any hints on these JVC's that may show me the panel used or the replacement LED strips to get?

Thanks for any help.

[diif]

Re: JVC LT-65N550A LED Issue

Photos always help. It will be a chassis common across a few brand names. The only bit that is JVC is the screen printing on the front of the TV.

[budm]

Re: JVC LT-65N550A LED Issue

Need to see pictures so we can see what we are dealing with.

[RooTV]

Re: JVC LT-65N550A LED Issue

So JVC's are so generic they are used in many different brands?

I emailed JVC for spare part info and was just told that the led strips are not available as a spare part. So helpful.

Im working on the pics. I assume you are referring to pictures of the back cover off or the whole back of the tv?

[budm]

Re: JVC LT-65N550A LED Issue

The whole back of the TV so we can see how all the boards are connected together.

I do not know how up to date this info is:
https://www.consumerreports.org/tvs/...hat-they-seem/

[RooTV]

Re: JVC LT-65N550A LED Issue

here are some photos...

[neilc6]

Re: JVC LT-65N550A LED Issue

You are not likely to find replacement strips for those Chinese models. They are branded RCA/Westinghouse/Proscan/Haier in North America. I usually repair the strips, move it to the edge (in case it is noticeable), and turn down the backlight level in the service menu (source-2-5-8-0 or menu-1-1-4-7) under Panel Settings. Only typically find 1-3 burnt out with the protection shutdown. Most of these models use Samsung compatible 3V LED modules with the small pad positive. The default picture modes run the backlights at 100% so very common to see backlight failures after 2 years.

From the Tcon label, tcon part number is 55.65T07.C07 which is an AUO panel. Looks like it is used on Vizio E650i-A2. From an ebay listing, strips could be part 48.64S03.L01 with one listing there for used strips. Most manufacturers (and authorized service centers) consider the backlight part of the panel assembly and not replaceable.

Also when removing the panel, there is double-sided foam tape holding down the panel boards. There may also be double sided tape on the panel itself as well.

[RooTV]

Re: JVC LT-65N550A LED Issue

Wow i didn't think it would be that confusing.
Thanks for the heads up

[mmartell]

Re: JVC LT-65N550A LED Issue

Did you verify the led driver circuit is ok ?

[RooTV]

Re: JVC LT-65N550A LED Issue

No. I just assumed the led's were the issue as that is what the guy told me.
Probably not wise eh?
What's the best procedure for checking led driver circuit?

[budm]

Re: JVC LT-65N550A LED Issue

https://www.badcaps.net/forum/attach...5&d=1597195824
Ah, so I thought you have already done the Voltage testing to come up with Bad LED conclusion after Voltage testings were done.
You need to check the COLD SIDE Voltages of each pin of the connector using chassis GND ref. The connectors have pin names so you MUST put down the pin names follow by the Voltage readings fir each pin when TV is OFF and when TV is turned on.
Did you buy the LED tester yet?

[neilc6]

Re: JVC LT-65N550A LED Issue

Every RCA/Proscan/Westinghouse TV I've looked at that turned on with no backlight had bad backlights. The protection shutdown is doing its job and protecting the power supply.
Haier models tend to have eeprom issues as well but the symptom is the the tv had a standby light but didn't turn on.

[RooTV]

Re: JVC LT-65N550A LED Issue

Yes i have the led tester

[budm]

Re: JVC LT-65N550A LED Issue

Yes i have the led tester

Well, did you use it to test and find out what it shows for each LED strings?
I did not see that was done in the first post.

[neilc6]

Re: JVC LT-65N550A LED Issue

From your picture, you have two banks of LED strips (small 2 pin connector with black and white wires). You can power each bank and compare voltages. I would expect one to have a shorted LED and report about 3V less than the other if the LEDs are evenly distributed. You can also power up one bank of the LED with the tester instead of the power supply and turn on the TV to check the screen and make sure the video is working. Works better than the flashlight test.

[budm]

Re: JVC LT-65N550A LED Issue

From your picture, you have two banks of LED strips (small 2 pin connector with black and white wires). You can power each bank and compare voltages. I would expect one to have a shorted LED and report about 3V less than the other if the LEDs are evenly distributed. You can also power up one bank of the LED with the tester and turn on the TV to check the screen and make sure the video is working.

I wonder why he did not perform the simple test with LED tester.

[RooTV]

Re: JVC LT-65N550A LED Issue

I havent performed test because I have not had a chance to do anything with it yet, apart from pull off the back cover.

I finally have time to do some testing today.

This, and I am still really new to all this and wasn't sure what to test or how to test it, so I need to give myself a lot more time than an experienced person to do it

Im sorry I have come here asking questions half baked, but my inexperience is showing.

[RooTV]

Re: JVC LT-65N550A LED Issue

Ok, game over.

As neilC said, I found double sided tape holding the screen down, and that led to the screen cracking, regardless of how careful I was.

Parting it out now.

Thanks for all your help.

[neilc6]

Re: JVC LT-65N550A LED Issue

You can still check the LEDs with the tester so you have an understanding of how to use the tester. Measure the voltages from the connectors but you can observe the LEDs lighting up with the panel removed. Each strip can also be checked with the panel removed. With a short, it's not necessary but with an open LED, you need to isolate it.

[RooTV]

Re: JVC LT-65N550A LED Issue

yep. doing that now