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Old 05-25-2022, 03:24 PM   #21
Diah
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

for me its not panel fault.. the set trying to kill him self ( suicide ) LOL
+ 8Years old and picture setting dynamic !!! if one LED its ziner diode leaked.. there will be pulling of currents not Volts. if you measure currents you will find it.. even with this age of TV LVDS could be dried out. changing at Resistances of one of its PINs. clean them and it sockets could make change.. reduce BL could make change.. turn off 3D profile could make change too.. just be nice to it and care of its age pls.
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Old 05-26-2022, 08:18 AM   #22
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

A few assumptions
Which module can move the image vertically?
The panel? I do not think so. Streaks, lines, dark, etc but not moving an image seems to me.
T-Con? Definitely, which is exactly what that module does. However, my replacement module does the same.
Main module? Yes it could be, if it delivers such an image T-Con cannot solve that. But how to test that without a replacement main module?
I come back to the power supply. Could it be that the quality of the delivered power supply compromises the functioning of other modules? Quite possible, I think.
Visually, I see nothing wrong on any elco on the PSU. To avoid having to unsolder each capacitor to measure it, I would first consider the following experiment.
Through an external power supply I offer the PNL 12V and UR 13.2V, before starting the device.
If he then works normal, maybe I can hang a scope on those lines, but in any case I have to look in the direction of capacitors on the PSU.
Do you think the experiment with external power is worth to try?
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Old 05-26-2022, 10:52 AM   #23
Diah
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

this experiment will not work. because the Main boards full function at Dc to DC need another parameter to switching on like BU5V /AC_DET / ERROR,
Alternative to this you can run the set will less load... BL down... sound down... wifi plugged out etc.
the questions,now you are talking on the image jumping as we saw at your second video.. which are different from first Video you upload. is this new behavior ?
other question did you log in Inspection mode to see if there are error as suggest at post#18?

Last edited by Diah; 05-26-2022 at 10:56 AM..
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Old 05-26-2022, 02:56 PM   #24
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

You can scope your power supply and main board voltages for fluctuation.
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Old 05-27-2022, 02:17 AM   #25
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

The set appears to operate normally the last few days.
Reason? More in use lately, warmer room temperature, mechanical manipulations, ...
The vertical image jumping is there sometimes on top of the darkening. It's the extra factor of bad start-up indication.
I've checked the first page of the inspection. See included picture.
Lamp Error = 0
There are some monitor err causes.
1) 21 B00011422:40
2) 21 B00011399:05
3) 21 B00011251:35
4) 1A B00011239:26
I hope this give a clue where to search.
Next I'll monitor the voltages during start-up with a scope.
Attached Images
File Type: jpg IMG20220527094108[1].jpg (540.8 KB, 7 views)
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Old 05-27-2022, 03:19 AM   #26
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

so the inspection mode pointed to 21 PCB Panel power failure

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Old 05-27-2022, 03:35 AM   #27
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

Okay. that's the PNL 12V on the PSU board.
How did you figure out this detail?
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Old 05-27-2022, 05:36 AM   #28
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

Quote:
Originally Posted by SmartSarah View Post
Okay. that's the PNL 12V on the PSU board.
How did you figure out this detail?
early i uploaded for you the service manual at my post #6 .. display code detail listed on Page 63
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Old 05-27-2022, 06:20 AM   #29
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

Oh, I read only the page you indicated me earlier. I didn't realise what an information treasure you posted to me. I am sorry for this aberration.
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Old 05-27-2022, 06:48 AM   #30
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

as you mentioned before
Quote:
Originally Posted by SmartSarah View Post
The set appears to operate normally the last few days
so you need right now only to reset the error at page 2 of inspection mode. and if the fault back in future days.. you can see the error code again and work on it rails at PSU
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Old 05-28-2022, 03:08 AM   #31
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

Update - the problem returned
Inspection
- MONITOR ERR CAUSE: all 4 positions "00 0000000000000"
- BL voltages 190V, current 22mA (measured with DC current clamp)
Observations
- I've noticed extreme latency on right side during inspection (see Ghost latency 1 video)
- I made another video while toggling through LCD TEST PATTERN 2 (the other are not supported). see LCD TEST PATTERN 2
- After power off, the last image is noticeable and fading out on the right side during about 10 seconds (no video made)
Could it be like a bad ground in the panel?
Attached Files
File Type: zip Ghost latency 1.zip (4.11 MB, 2 views)
File Type: zip LCD TEST PATTERN 2.zip (8.97 MB, 2 views)
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Old 05-28-2022, 04:13 AM   #32
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

fading image on screen. i had one time faced it at Hisense and i do post it over here.. i just solved it with panel driver firmware which i took from friends in china.

so i suggest you at my post#7 to put back yours original T-CON. did you ?
at same service manual was advised to inter adjustment mode in case changing module of main or panel.. but i don't think you need this if you put back the original t-CON and did reset from inspection mode page 2.

EDIT: if you did have same fading remain with original T-CON. i would change all caps at Panel_12V rail on PCB

Last edited by Diah; 05-28-2022 at 04:32 AM..
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Old 05-28-2022, 04:44 AM   #33
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

The original T-CON has always been in place. I just swapped it shortly but since it made no difference I installed the original back.
Ok, at least I'll start measuring the 12V caps. I'm not sure if I've replacements available on the shelf. Would it hurt if I additional place caps in parallel?
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Old 05-28-2022, 05:07 AM   #34
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

mathematics wise yes.. but as currents who knows and we don't have any record under hand.. so i would just measure ESR out side the circuit. if it was out of the order.. u can do this experiment until u got exact value
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Old 05-28-2022, 06:47 AM   #35
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

I've measured 6 x caps 470F, all good. C7133, C7130, C7123, C7120, C7950A, C7950B.
Replaced C7123 by a new 1000F. No difference.
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Old 05-28-2022, 10:41 AM   #36
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

So, I don't think main board is responsible for erasing image. That is done at t-con/panel.
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Old 05-28-2022, 03:58 PM   #37
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

Quote:
Originally Posted by SmartSarah View Post
I've measured 6 x caps 470F, all good. C7133, C7130, C7123, C7120, C7950A, C7950B.
Replaced C7123 by a new 1000F. No difference.
if you test all were good why you replaced C7123..
it sound for me the error 21 TV registered could be related to Test you did to ribbon disconcerting one side cable or LVDS before since no more error listed.
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Old 07-02-2022, 05:20 AM   #38
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

Small update on this.
It's all in the boot of the TV.
I follow this procedure nowadays.
Bad image -> pull the mains socket -> reboot (= cold restart with large red SHARP logo).
Again bad image -> repeat pulling the mains socket for a few seconds.
Good (= steady SHARP logo), so not jumping, not fading to the right -> leave it on. And than it stays fine, for weeks!!!! until next reboot.
Brightness or backlight has no influence. Last "session" it worked fine on dynamic setting for 3 weeks.
The only reason for this behaviour I can think of is that one or more (passive) components is degrading and troubles some syncing during start-up.
But besides blindly de-soldering and measuring capacitors I have no clue where to start diagnosing.
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Old 07-02-2022, 05:34 AM   #39
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

wonder if it could be a memory problem?
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Old 07-02-2022, 05:52 AM   #40
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Default Re: Sharp LC70LE747 Flickering - darkening gradually to the right side

also wonder if it might be a bad/intermittent connection in backlight circuit.
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