Riddled TV Repair Forum

AJD · Joined: 21 Aug 2008 Posts: 2

Hi, i have a Phillips 27PT543S37A L01.1U AC-7638

TV seems to work great for about 4-5 seconds then shuts off. Picture is clear, sound is fine. But it seems like some safety circuit is tripping and causing the TV to shutoff. The green power light remains on, and if i hit power the green light will go out. If i wait a second and hit power again, the TV will come on and repeat the process all over. I have replaced capacitor 2455 but didn't really do anything. Also, if you change channels repeatedly every 3 seconds the TV will never shutdown...

I read that this model of TV is notorious for dying... hopefully there is a simple common solution to the problem.

Thanks

EDIT: I should probably mention that the person who gave me this TV informed me that something was spilled in it (the outside case is sticky) but looking inside the TV i didn't see anything that was obviously broken/burned.

EDIT: Okay, i noticed one more thing. When the unit shuts down, if i press channel up/down it will come back with a grey screen with horizontal lines... but i can still hear audio. I noticed http://www.riddledtv.com/repair/philips.html and says the fix for the horizontal lines on a magnavox 25" is to "Replaced filter capacitor." Any ideas on where that is? Anybody got any suggestions?

EDIT: Okay noticed one more thing, the set seems to turn of as soon as the EPG goes away, i.e the Channel number and the "Stereo/Mono" thing. Any ideas?

Thanks

Google

jack of all trades · Joined: 08 Oct 2008 Posts: 1 Location: midwest

Phillips TV, model:27PT543S37A REPAIR
SYMPTOM:
Clicks and turns off after turning on set when cold. Have to turn on and off several times to work, or keep changing channels, right side of screen is black for a while.
PROBLEM: It is almost always a bad transistor and a bad capacitor. (about $0.70 in parts)
SOLUTION:
This repair is fairly straightforward. You will need a soldering iron, a solder sucker, and a small torx bit. Unplug the set. Lay the TV on the floor, screen down. Remove the torx screws holding the rear cover on. There should be 10, (don't forget the 2 by the input panel). You will see 2 circuit boards, the one of interest is the large one near the bottom of the set. This board has a retainer clip on each side that needs to be pulled out to allow the circuit board to slide out. Slide the board out about 5-6 inches. You might need to support the board so it doesn't slide back down into the TV set. This circuit board should have numbers by each of the components. You want to look for 7461 (transistor) and 2455 (capacitor). They are located right next to each other near the center of the board. The transistor will usually overheat and discolor the circuit board immediately around it. Warm up the soldering iron and get the solder sucker ready. Heat up the solder joint while removing excess solder with the sucker. Once the transistor and capacitor are free, check the numbers on each. The capacitor (round cylinder) should have "47uf" on it. The transistor should have "C33725" on it. You can order these parts from Digi-Key (google it) for about $2.50 including shipping if you use USPS option. The part numbers are: 493-1060-ND for the capacitor and BC33725-ND for the transistor. Once you get your parts, solder them in and check TV operation. It should work as it did before. (Wouldn't it be nice if these companies could focus on quality rather than saving $0.04 here and there??!!??). This repair can be done by anyone familiar with a soldering iron in about 30-45 minutes their first time. Good Luck!!

scotty71 · Joined: 27 Oct 2008 Posts: 2

Thanks for that info. I used your answer to hopefully fix my TV that was showing the same problems. I did damage board slightly at the transistor pad, but I put in a "fix"

Appears here that only the cap was bad and measured around 5uF. So I just replaced it. I did however solder in sockets at both locations so I could change either of them easy in the future.

The TV now powers up at the 1st push of the power button and comes right on, but I have yet to keep it on for very long to see if it will shut off. The person I got it from said it would shut off after about 2 Hrs, it you got it to even come on.

I was wondering how many parts on this board on not watertight as this board at times has had flowing water running over it as the TV was put outside after it started to mess up. The people live near a creek and sometimes the water flows around their house after a large rain. I did have to clean off nearly a 1/2in of dirt from the board

There are two resistors at the back of board near the plug that goes to the CRT board. They are 150ohm each and maybe 1/8 watt. The board is very discolored under them. I was going to replace them with a 1/4 or 1/2 watt resistor, but am putting on doing that until I can find out what circuit they are a part of on the board.

Numbers 3477 3478

thanks