Hisense TV Panel issue - Page 1
Forum section: electronics / repair

author: LOL_Duck
author_rank: Newbie
timestamp: October 15, 2020, 02:54:42 pm
content: I have a Hisense 55" LED/LCD TV that's 3.5 years old, and just started playing up. I'm quite sure it's out of warranty, but I've still yet to check what my options are, if any, as it just started happening right now.After it has been on for a while, the panel will suddenly shut off (everything, including OSD). The image becomes "corrupt" and freezes on a frame as it slowly fades out over a 10-second period. It also slowly turns red as it's fading out. This occurs on any input, TV, HDMI, etc. The backlight and audio however still remain fine. The only way to get the panel working again is to turn the TV off and on. It appears if I instantly turn it back on, it might only last minutes before I lose the image again. But if I wait a little longer before turning it on, it could last a couple of hours.I've yet to record a video of it, as it's very random, but will do if need be and I get an opportunity.If it so happens that the warranty/australian consumer law no longer covers the TV, what are the chances of it being a (slightly) easy fix? Thanks.LINKS TO RECORDINGS:https://streamable.com/06guk5https://streamable.com/dm72lh

author: m k
author_rank: Super Contributor
timestamp: October 15, 2020, 06:35:07 pm
content: It seems you need a hair dryer and some cold spray.With luck you don't break it totally and with more luck you'll find the fault.Cooling the faulty one can be very peculiar.Mean that the part you are spraying is not it even that it very much look like it and the real one is the other one that gets only some doppings of your spray.

author: shakalnokturn
author_rank: Super Contributor
timestamp: October 15, 2020, 07:34:42 pm
content: A couple of pictures of symptom, mainboard and T-Con may get people more involved.Out of experience LDO voltage regulators or the P-MOS for T-Con board Vcc switching on main board can give similar symptoms.

author: limtk55
author_rank: Newbie
timestamp: October 17, 2020, 03:01:59 am
content: I think its a Gamma IC problem. Depending on the model of your TV, the Gamma IC is usually located on the TCON board, or embedded on the PCB attached to the panel with flex yellow flat wires. To know which is the GAMMA IC, just look up the IC ident datasheet on the internet. There is no other way unless you're in the trade.Usually the failure of this IC causes image distortions and solarisation (redness of images). You might want to check the gamma IC voltages usually marked as GM or CM (1 to 14) ie. GM1, GM2 .... GM14. Usually these voltages go in ascending or descending order, and any break in the order signals a faulty Gamma IC.OK : 1V, 2V, 3V......13V, 14VNot OK : 1V, 2V, 3V,2V, 5V.....14VIf the test confirms it, just try replacing the faulty Gamma IC and see if it fixes the issue.Let us know the outcome!

author: LOL_Duck
author_rank: Newbie
timestamp: October 17, 2020, 05:20:18 pm
content: Thanks for the responses. I'll definitely refer to this thread in future if I need to. But interestingly it has been fine the past couple of days. I even had it on for about five hours before switching it off and the panel didn't shut down at all. I'm not totally confident it has somehow "fixed itself" just yet, but then again stranger things have happened.In regards to the redness, it only does that for a couple of seconds before the screen has fully faded out. As for the image corruption when the panel loses the image, I'm not sure if that's the "nature" of LCD displays with the "liquid" distorting the image once power is lost, or if it is in fact an IC causing it.Basically the panel is either 100% fully working, or not working at all. There's no in between, except when it stops working... the 10-15 where it fades out and develops a red hue as it's fading.

author: LOL_Duck
author_rank: Newbie
timestamp: November 02, 2020, 09:30:43 am
content: So it has recently been OK (or taken many hours before the fault occurs), but only because of cooler weather by the looks of it. Now that today is a much warmer day, it returns.Pics attached. The IC on the T-CON board is NT72333TBG.Again, what happens is, the LCD loses power/picture, but everything else including backlight still works 100%.(Found a T-CON that's exactly the same from the same TV model, that wasn't too expensive. Hopefully that'll do it when it arrives.Also, quite confident it's the T-CON board. When it fails, there is still power (12 Volt rail, 3.3 Volt rail etc) from the mainboard going into the T-CON board, but the 'output' from the T-CON drops down to virtually nothing.I'm almost convinced that the reason they don't put fans in TV's is because they want them to fail after a few years...some things run quite hot.)