Can a small crack kill the whole panel?

[Gorrillasnot]

hello all,

After repairing the LEDs on a 50" TV (Sharp LC-50LB370U) I managed to crack the LCD in the lower left corner as can be seen in the first pic @ post #67 seen here https://www.badcaps.net/forum/showpo...0&postcount=67.

I have tried retesting all the voltages which were normal, and reseating the t-con cables, running with only 1 t-con cable connected at a time etc. but I cant get any picture to display at all on the screen.

My question is could a small crack like that kill the whole panel?
Is there anything I can try before scrapping the TV?

thanks

[dick_barton]

Re: Can a small crack kill the whole panel?

There are plenty of cracked screen that display colours/strips/pattern across the screen so I would have thought there would have seen something on the screen.

[Gorrillasnot]

Re: Can a small crack kill the whole panel?

There are plenty of cracked screen that display colours/strips/pattern across the screen so I would have thought there would have seen something on the screen.

That's what I was thinking..I've seen screens with way worse cracks display at least something.

I went back a double checked my voltages and all were the same except for 1. DIM = 0 standby and 3.2v power on and is now 2.7v after fixing LEDs.

Also before the LEDs were fixed the black wires at -VLED2 and -VLED1 showed 0v powered on or off and now show 4.5v powered on.
does this seem normal?

thanks

[Gorrillasnot]

Re: Can a small crack kill the whole panel?

does those voltages seem about right?
maybe a bad t-con?

thanks

[tom66]

Re: Can a small crack kill the whole panel?

I can confirm that a small crack can kill an entire LCD panel because I've done it before, and all that was visible was a very very faint vertical banding pattern.

[budwich]

Re: Can a small crack kill the whole panel?

your "observations" are somewhat "thin". Are you saying that you get nothing as in no back lights, no white screen (one tcon panel connected)... ???? flashing codes???

you likely need to go back to basics and verify / list all the voltages that are printed on the connectors of the boards.

having said that, is it really worthwhile since the screen is cracked.

[Gorrillasnot]

Re: Can a small crack kill the whole panel?

your "observations" are somewhat "thin". Are you saying that you get nothing as in no back lights, no white screen (one tcon panel connected)... ???? flashing codes???

you likely need to go back to basics and verify / list all the voltages that are printed on the connectors of the boards.

having said that, is it really worthwhile since the screen is cracked.

Sorry about that..to be more specific when the TV is first plugged in it has the red standby light, after pressing the power button the standby light blinks red 7 times then turns blue, the backlights do come on, but there is never any image or change in whats displayed on the screen..just a dark blank screen as seen in the pic below.
Running with 1 ribbon cable disconnected on the t-con doesn't give a white screen or otherwise change what is being displayed. I've tried each side being disconnected (one side at a time) and nothing changes on the screen.

Ive retested all the voltages and they all were within spec..the only difference between before and after fixing the LEDs is the connection labeled 1. DIM = 0 standby and 3.2v power on before fixing the LEDs and is now 2.7v powered on after fixing them.
Also the -vled2 and -vled1 are now showing 4.5v powered on.

It's probably not really worthwhile to get working, I just hate to give up.
If I could get it going I thought I would use it in the garage.

thanks

[freakaftr8]

Re: Can a small crack kill the whole panel?

I'm assuming you have checked to make sure the you have 12 V going to the tcon board? How about tcon outputs? See anything on the ribbon connections in excess of 20v?

[ajshoe]

Re: Can a small crack kill the whole panel?

done the same thing on a 50 inch led set. when installing the display back into frame I created a very small "chip" on edge of display - messed up set - garbage can. could not believe I did that !
When removing and installing display screen - be VERY careful & patient.

[budwich]

Re: Can a small crack kill the whole panel?

thanks for the extra info. You should list the voltages / pins that you have checked (designations) along with any readings as your "normal" may not be "normal". Further, have you tried any "forced on power up sequences" since it appears you have some form of error code... which have you tried determining what that might be / mean? it wouldn't happen to be 2-5 flashes... :-)

[Davi.p]

Re: Can a small crack kill the whole panel?

I don't understand this thread, even if you succesful bring back an image, that will be damaged, you can get more selling good boards than selling an entire defective tv!

[budwich]

Re: Can a small crack kill the whole panel?

I don't understand your comment. IF the OP can't get some sort of display to happen with the set and he has no other way to determine if the cards are working correctly, selling them thereafter would be a bad thing for him and the buyer.

[Gorrillasnot]

Re: Can a small crack kill the whole panel?

thanks for the extra info. You should list the voltages / pins that you have checked (designations) along with any readings as your "normal" may not be "normal". Further, have you tried any "forced on power up sequences" since it appears you have some form of error code... which have you tried determining what that might be / mean? it wouldn't happen to be 2-5 flashes... :-)

At CN9100
15.v = 0v (standby and power on)
12v = 11.8v
12v = 11.8v
12V_A 11.8v
GND
GND
PS_On = .12v standby and 3.7v power on
1. DIM = 0 standby and 2.7v power on

the LED connector on PSU
+VLED2 65.4v then spikes to 96.4v then goes back to 65.4v
+VLED1 same as above
-VLED2 0v standby 4.5v power on
-VLED1 same as above

I have tried the chanel down + input power up sequence and it didn't change anything.
I don't think the TV is giving an error code( i could be wrong) the front LED always blinked red 7 times before turning blue (same as when TV worked)

I don't understand this thread, even if you succesful bring back an image, that will be damaged, you can get more selling good boards than selling an entire defective tv!

Depending on the damage if it was just that small area in the corner I figured I could use the TV out in the garage.
I wasnt looking to sell the TV..mainly just tinkering and trying to learn at this point.

thanks

[budwich]

Re: Can a small crack kill the whole panel?

have you checked any fuses on the tcon?

[Gorrillasnot]

Re: Can a small crack kill the whole panel?

I checked the fuse F101 on the t-con and it showed .4ohm on 200ohm scale.
Is there more then 1 fuse on the t-con?

thanks

[freakaftr8]

Re: Can a small crack kill the whole panel?

Here's the deal. Yes the crack has hindered the gate driving of the panel, You're area on the bottom crack spot is right where the 1st gate drives the horizontal span of the panel and every other gate consecutively needs to drive with the hand off of the 1st section. Sense that section has been damaged 1st then there is no handshake and no passive information going to the next gate thus for yes this can wipe out the whole panel it is rare but it can happen

[RJARRRPCGP]

Re: Can a small crack kill the whole panel?

Reminds me of this, thus, I try my best to not drop anything or bump anything with an LCD!

https://www.badcaps.net/forum/showpo...6&postcount=58

[Davi.p]

Re: Can a small crack kill the whole panel?

I dont know if you done other errors, lets suppose of not, it's a simple equation, if a broken glass brokes the tcon it's not useful to fix it or change it, it will break again...

[budwich]

Re: Can a small crack kill the whole panel?

if the 15v isn't ever there, then it might be a problem. Based on my limit experience, that gets delivered to the panel.

[Gorrillasnot]

Re: Can a small crack kill the whole panel?

i tested both sides of the t-con fuse and get 11.8v so its getting power. I don't know how else to test it.

i havent tested the 15v after fixing the LEDs but before i fixed them and before damaging the LCD it has never showed any voltage.

thanks