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**aaronwt6** · 11-12-2018, 02:01 PM

Re: Sony KDL-46HX729 Vertical Streaking

Looks like panel failure, unfortunately.

**Charleyd** · 11-12-2018, 06:15 PM

Re: Sony KDL-46HX729 Vertical Streaking

OK, but what really fails when a panel fails, besides individual LCDs failing giving stuck pixels (actually pels) or lines?
As I try to imagine what is going on with the display, it seems that the signals that feed into the sides of the LCD panel (Gate drive?) are all staying "ON" instead of switching ON only when they are supposed to and then switching back OFF when that row is finished. Now consider that there are redundant gate signals feeding in from the opposite edges of the display. Since the display still bears some resemblance to what it is supposed to look like, it strikes me that perhaps the problem with the gate drivers only exists on one side while the good side is still trying to drive the rows correctly. (I expect that the problem with the gate drive could be coming from the T-Con, i.e., the T-Con could be failing to send the correct timing signals to the gate drivers on one side, or the problem could be with the gate drivers on the side tabs themselves.) I have read many posts talking about peeling off the side tabs from the panel when there is a problem with them, e.g., a short in one of the gate driver ICs. So I am wondering whether the problem with the subject TV could be rectified by removing the gate driver tabs on one side of the panel (?).
It should be possible to test my theory of the problem by disconnecting one or the other of the flat ribbon cables between the T-Con and the panel to see if this makes the problem disappear for one side of the panel or the other. Since the TV is not in my possession, I was hoping that someone had tried this for this symptom already so that I can make a decision on whether to purchase the TV.
Comments?

**Davi.p** · 11-13-2018, 01:35 PM

Re: Sony KDL-46HX729 Vertical Streaking

I already owned a Samsung tv with this common fault, i've done many tests like the thread here in this forum, (LE40A756), i've ended up removing one side's tabs with no improvements, the half connection test on tcon showed both halves with the fault. Yes it seems a gate driver fault, i have not tried a replacement tcon, someone on Italian forum done it with no solution but this is not a proof 'cause many faulty tcon are sold as good in the market. It can be may be a clock signal problem, ho knows? What i haven't tried, i and if i owned again a tv like that i would try it for sure, it's a reflow of the tcon main chip, but the chances of success are few 'cause someone on yuotube already have tried it (see EEVBLOG>"Samsung dumpster dive")..