LG42CS570 Screen Acts Like It Needs To Warm Up

[CloakedWarrior]

My Tv was manufactured in 2012 it is an LG 42' LCD Tv Model# 42CS570-UD.

The Problem I seem to be having is when the Tv is powered on after being off for a period of time the screen freezes and glitches for about 30 to 45 minutes before returning to normal operations. The problem has since been replicated by the air around the Tv being cooler than the operating temperature of the Tv it will cause issues until the air is warmed around the Tv. I have powered on the Tv with only the right ribbon being unplugged from the T-con board with the screen only remaining black. Again with only the left ribbon being unplugged powers on in the same glitchy fashion only more pixelated. Any help in this department would be greatly appreciated hence I am no expert lol Thank you in advance for your time and effort.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Just a follow up the TV has been off for 2 days and I powered it on this morning and to start off the LG logo screen will appear upon start up (full screen) after a brief second it will slowly fade away. After initial start up the top 1 inch of the screen will start showing normal picture. I have let it run for 30 minutes now and the picture seems to be growing from 1 inch making its way to the bottom of the screen. Any suggestions or help would be greatly appreciated.

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Just saw a similar problem here, try cleaning your connections and make sure they are not loose.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Any specific ones? Or just in general?

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Tcon connections with isopropyl alcohol and a q-tip, never force a connection, not saying that you would but once in a while you get somebody who yanked them out and ruined them, on the ones going to the panel theres little clamps that you flip up with fingernail, be very careful they are delicate. Maybe try unplug and replug the lvds connector from tcon to main and same for connector from power board to mainboard, might not be the problem but sometimes you get a bad, loose or dirty connection.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Okay thank you for your advice I will give this a try and follow up asap.

[bman4]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Could be shorted tab driver feel around frame for warmth!

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Update: I cleaned the ribbons to the drivers both on T-Con side and driver side. I also cleaned the connector to the main board and T-Con board. The behavior did not change.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Update I left the TV off for 2 days and the symptoms are now different. When the Tv is powered on Cold it will display the LG start up logo as normal full screen; after start up the top of the screen will display 1 inch of source picture full screen horizontally; the bottom portion of the screen will be cloudy gray vertical lines; sound is normal no other issues. After start up and approx. 40 to 45 mins of running source the screen will slowly grow from 1 inch to 3 inches and so on and so forth until it reaches about mid ways of the screen horizontally; the bottom will then glitch back and forth until returning to normal operations until powered off for another amount of time.

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Tcon maybe?

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Tcon here, model seems the same. https://www.ebay.com/itm/LG-42CS570-...AbuW:rk:3:pf:0

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Going to give the T-Con board a try. Any possibility that it could be the solder joints on the main board? I've seen videos of individuals putting the main board in a 385 degree oven for 10 minutes or so to re do the joints because of the processor solder becoming cracked underneath.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Update : I have replaced the t-con board with no resolve to the issue.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Could be shorted tab driver feel around frame for warmth!

Do I feel around the frame at power up or after being on for sometime?

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

If it does it should get hot pretty fast shouln't take more than 15 minutes.

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

And the numbers on the sticker of the tcon matched? https://www.shopjimmy.com/lg-6871l-1...-con-board.htm

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Wondering if it's a weak or bad capacitor somewhere.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

The T-con did match just the same exact issues. Not sure about a weak capacitor but I did replace 2 capacitors on the power board that seemed to have a slight bulge to me but upon checking them they were good.

[CloakedWarrior]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

I noticed that while the Tv is on if I tap on the top of the screen where the I'm guessing the PCB or LCD driver boards are the screen seems to change and correct itself a bit but not until there is a significant amount of heat surrounding the boards with the case on. Ribbons are clean. I clean both there end and t-con end when I installed the new t-con board.

[nomoresonys]

Re: LG42CS570 Screen Acts Like It Needs To Warm Up

Ok, seems like a bad tab bond, need to very carefully strip down to tab bonds, a lot of times a shim will make the picture good, only the bad bond needs the shim, I think I saw some use tape, I'm using one I shimmed a year ago right now as pc monitor.