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Old 11-26-2016, 05:14 AM   #21
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Default Re: Hitachi LE55A6R9A - No backlight

I'll make the orders soon, but I may have to wait a few weeks with the holidays and all.

In the meantime, a question. The LED tester can be used to test the strips prior to opening the chassis and messing with them, yes?

I'm not super hung up on saving this TV, more interested in practice, so I'm not opposed to opening it up. Still, if this particular unit can be salvaged without risking damage that's a plus. And I can, of course, practice that on a different TV in the future.

Last edited by PorkfriedPanda; 11-26-2016 at 05:15 AM..
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Old 11-29-2016, 03:47 PM   #22
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Default Re: Hitachi LE55A6R9A - No backlight

Bought the LED tester, confirmed that bottom LED strip works, top LED strip doesn't.

Exploring options from here, watching vids, etc.

Thanks for all the info guys
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Old 11-29-2016, 04:26 PM   #23
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Default Re: Hitachi LE55A6R9A - No backlight

The led tester will allow you to test each led strip or individual leds to verify which leds are faulty or show up any led strip connection problem. However it does mean removing the led panel carefully.
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Old 11-30-2016, 03:20 AM   #24
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Default Re: Hitachi LE55A6R9A - No backlight

And don't forget to test your meter !
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Old 11-30-2016, 04:25 AM   #25
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Default Re: Hitachi LE55A6R9A - No backlight

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The led tester will allow you to test each led strip or individual leds to verify which leds are faulty or show up any led strip connection problem. However it does mean removing the led panel carefully.
Of course, that's what I'm studying up to do.

I'm considering buying the little dedicated ShopJimmy gizmo to detach the single LED, and maybe some LEDs and diffusion covers so I can do this again if I have to.

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And don't forget to test your meter !
Definitely. I keep forgetting to do that, next time I've got a little spare time I'll unhook a car battery and check it.
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Old 12-09-2016, 03:44 AM   #26
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Default Re: Hitachi LE55A6R9A - No backlight

Car battery ? How about a simple 9v or AA even.
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Old 03-18-2017, 07:08 PM   #27
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Default Re: Hitachi LE55A6R9A - No backlight

I'm bot sure what the thread etiquette is on this forum so if I have breached it with this post, I apologize in advance. I'm bot sure if I can even start threads yet.

Anyway, I have the same tv as the OP of this thread. As far as I can tell (watching youtube vids), all 3 of the main boards in my tv are good.
It has sounds but no video.

The flashlight test shows me images very light when I hit the menu button.

I now find myself still unsure how to proceed. It sounds like my 2 potential issues are:
Led inverter board or
Led strips themselves

So, do I just buy both and go with it? I prefer to be a cheap-a$$ when possible.

Also, is it an absolute must to buy specific led strip "kits" specific to each model tv, or can I just sub in some led strips I picked up on ebay for $10. These particular ones run off of 12vdc I believe.

A little about me, I am a competent arcade monitor (crt) repair guy, and overall good at repairs on arcade games and pinball machines.

I certainly encourage input, and will not be offended easily.
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Old 03-19-2017, 04:35 AM   #28
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Default Re: Hitachi LE55A6R9A - No backlight

Have you read through the thread and carried out any of the tests suggested earlier in the thread?
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Old 03-19-2017, 08:52 AM   #29
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Default Re: Hitachi LE55A6R9A - No backlight

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Have you read through the thread and carried out any of the tests suggested earlier in the thread?

It seems like most of the thread is attempting to determine if his meter works. ��

If i remember correctly, the positions CN202 and CN203 , i was getting something like 270vdc out of 1, and a few vdc from the other.

I'm have not purchased an led tester (and probably won't).
I do believe, based on watching shopjimmy video(s) , that the power, t-con, and main board are all good.

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Old 03-19-2017, 09:13 AM   #30
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Default Re: Hitachi LE55A6R9A - No backlight

If you believe that you have 270V at the led connector of which they appear to be wired in series then I believe that you may well have an open circuit led.

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Old 03-19-2017, 10:06 AM   #31
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Default Re: Hitachi LE55A6R9A - No backlight

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If you believe that you have 270V at the led connector of which they appear to be wired in series then I believe that you may well have an open circuit led.
I definitely had 270vdc at CN 202.

So when you say "open circuit led"

are you saying a single LED or strip is bad?

Or is my voltage so high that a diode or transistor went out on the power board?

Again when watching a few videos I determined I had +12vdc at all of the points listed between the boards, +5vdc as well where it was supposed to be.
Shining a flashlight on the screen when powered on, got me some image in menu mode.
I am an absolute newbie at led/lcd tv repair (first attempt here).

thank you for replying
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Old 03-19-2017, 10:20 AM   #32
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Default Re: Hitachi LE55A6R9A - No backlight

i believe it works like this....If you have a very high voltage spike going to leds then that is a very strong indication there is an open led because it won't turn on to draw that power to put a load on it and draw to normal voltage ranges approx 1XX volts. When power supply detects this over spike high voltage it goes into protect mode and shuts it down due to open (blown) leds.
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Old 03-19-2017, 10:29 AM   #33
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Default Re: Hitachi LE55A6R9A - No backlight

The leds are connected in series, a little like old fashioned fairy lights, and when one goes open then no current can flow in the circuit to light the leds.

On the other hand it could be that a connection on the led strips inside the panel has gone open and that would cause the same fault condition. This has been the case in other threads here on the Forum where wire has been soldered across the connection to bridge the fault out.
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Old 03-19-2017, 11:26 AM   #34
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Default Re: Hitachi LE55A6R9A - No backlight

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The leds are connected in series, a little like old fashioned fairy lights, and when one goes open then no current can flow in the circuit to light the leds.

On the other hand it could be that a connection on the led strips inside the panel has gone open and that would cause the same fault condition. This has been the case in other threads here on the Forum where wire has been soldered across the connection to bridge the fault out.
So I could pull the panel open and look for continuity from the begging of the wiring to the end of the led strips? Somewhere in the middle there may be a loss of connection?

Or do I just buy the led strips (when they become available again from shopjimmy, unless someone knows elsewhere to buy them), and change them?
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Old 03-19-2017, 11:40 AM   #35
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Default Re: Hitachi LE55A6R9A - No backlight

It's a large screen so I would search the forum for information on hints and tips for lifting away such a large lcd panel without breaking it.
There are also "Youtube video's" which could aid you. There are also a lot of useful tips for testing the leds.
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Old 03-19-2017, 12:34 PM   #36
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Default Re: Hitachi LE55A6R9A - No backlight

Thanks gentlemen.

I think I replied earlier without reading all of recent replies to this thread.

Looks like I should learn how to carefully open this thing up and pull out my meter and look for a break in continuity.

It sounds like maybe I should do it with the power on as well and see if the voltage stops somewhere along the line?
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Old 05-01-2017, 03:11 PM   #37
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Default Re: Hitachi LE55A6R9A - No backlight

Well just following up on this one. Shopjimmy just got the led strips back in stock, so now I have them.

This is my first lcd/led tv repair, I've done hundreds of crt's. I have to say, this reflector shield or whatever they call it is a joke. It's paper thin and it's held down with double sided tape. I will report back with how much damage I do to it and also if changing the led strips fix my problem.
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Old 05-01-2017, 03:55 PM   #38
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Default Re: Hitachi LE55A6R9A - No backlight

well I got everything apart , started to install the new led strips and the busted at the connection between the 2 pieces.

I call shopjimmy and they said "yeah, manufacturing defect"

This thing is apart and at work and in the way. So in the trash it goes. oh well
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Old 05-01-2017, 03:59 PM   #39
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Default Re: Hitachi LE55A6R9A - No backlight

Just bridge the connections
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Old 05-01-2017, 04:02 PM   #40
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Default Re: Hitachi LE55A6R9A - No backlight

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Just bridge the connections
yeah if that had even a 1% chance of working I'd do it.

I am at work not at home where I have complete access to my work bench and all of my tools. I've done some pretty intricate soldering before and I don't believe I could pull this off if I had my tools at my disposal.

I love this site and I appreciate the insight, I probably won't be back because I don't intend to work on this type of tv ever again.

thanks guys
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