Question Philips LCD TV going wonky BUT works sometimes

Jul 26, 2020

I'm a non-technical person but follow tom's guide since long. Taking strength from the discussions on this site, I decided to try to troubleshoot my TV by myself. So please let me know if I make some rookie mistakes while posting on the forum.

I have a Philips TV, a few years old, model 42PFL3505/V7. In the last few months, the TV has been behaving erratic. The TV has 2 HDMI ports and 1 of those crapped out about 3 years back. I needed to use only 1, so I kept using HDMI2. Then back in April, HDMI 2 stopped working. I would keep getting a "no signal" blue screen. By this time, Covid-19 had hit and my kids' PS3 was connected using AV cable to TV1 input and worked fine for a couple of months. Occasionally I would see some "blips", like a sharp sort of spike, that came on the display and went in a fraction of a second. I'm not sure what that means. This week, the AV1 stopped working reliably and went wonky. I will describe the current state below.

Sometimes when switched on, it works fine for a while, say 10 mins - 1 day. Then, without notice, the TV display goes crazy, image being highly distorted and green and pink colored scratchy patterns on top. When the signal goes bad, the TV makes a VERY LOUD scratchy sound and I have to rush for the remote to mute the sound. This sound is like the old CRT TVs used to make when the had no input signal coming. The picture of this condition can be viewed here -

I tried the obvious things that are recommended on the forum - checking for loose cables, changing the HDMI cablesNone of these have worked. Today I took the TV off the wall and plugged out all cables. Waited several minutes then turned on. Still, the TV, even when in blue mode, displays some "symptoms". The "No Signal" box on the blue screen shows funny characters. Picture of this is attached here - The horizontal lines above and below the text did not used to be there earlier and they are showing these "reverse" apostrophe marks.

At this point, I'm not sure how to proceed but I'm willing to try opening up the TV and check for loose internal cables. If there is some kind of a systematic document or guide on what to try here, I would much appreciate if someone can point me to the right direction.

Appreciate your help on this.