Question about Philips 17PF8946A 17 in. EDTV-Ready LCD Television
I replaced about 10 electrolytic capacitors and a PWM controller IC (MC34067P). Fortunately, i found an almost identical schematic diagram in the internet, so i started troubleshooting. To make it short, i replaced most of the electrolytic caps and mylar caps in the Preconditioner stage and VsVa Power supply stage. And finally the PWM Oscillator IC (MC34067P). You have to make sure that the Preconditioner stage is running ok, with an output of 380 to 395 volts DC. There are two fuses on the board (in my 32FD9954), one is for the mains AC located near the mains connector coming from RF filter (two wire connector- large wires), the other fuse is in the middle of the board. You measure the DC voltage on this fuse on the middle of the board and it should be about 380volts or above. The real culprit is the PWM IC. Initially i replaced the MOSFET (STY34NB50F) in the Preconditioner, then the caps, then finally the IC. Then it worked!!! I put back the old MOSFET, it's not damaged, so now i have a spare one. Just replace the electrolytics near the PWM IC (2.2u, 4.7u, 100u, 1000u) I think the design problem is that the IC is nearly located to the heatsink which generates lots of heat. The IC deteriorated in time and the electrolytes in the capacitor evaporated due to the excessive heat inside the case. I'm thinking of incorporating 120cm computer fans at the back to suck down the heat. Happy troubleshooting. I have the necessary diagrams if you need it. regards, Valerio
Posted on Dec 21, 2006
I have 6 philips15pf5120 lcd tv's. all of them turn on but no pic. after many hours of research and tesing i found a fuse on the lcd back light power board that is open. i toke a risk and soldered a jumper across the fuse and to my surprize tv fixed. its been on for almost an hour now with no problems. the fuse is a board mount 2.5 amp right by the input connector. on a side not there are also two 150uf 25v caps that were buldged as well and replaced. hope this helps.
Posted on Aug 01, 2009
Actually, it doesn't really matter what Phillips TV you purchase the reality is that anything Phillips has produced in their TV line the last two years (if not longer) are ALL defective as is becoming more and more evident by the number of web sites croping up all over internet with complaints. The largest defect on their TVs is the on and off function that has become so endemic it would pay to check out here on internet at least one or two law firms already in the process of a class action suit against Phillips. Phillips, by now, needs to admit that they are very well aware of the problem yet continue to manufacture these lemons. Worse is the number of innocent consumers at the mercy of repair places that rather than take one possiblity at a time prefer to simply order a very expensive and seldom available computer board when, in fact, the problem can be solved by examining properly the "fixins" then going to Radio Shack and purchasing a fuse for less than $3.00 you can install yourself! In fact, you get four fuses in a box! The problem/solution: there is a small fuse that is accessible to the average person (though with utmost care) that blows out (no one has figured exactly how or why) that causes the off and on to continuously turn the screen black with triple blinks then two blinks then one, etc. At first the fuse does NOT appear to be blown so inspect closer. It's located right next to the "board" nearby as you open the back. In discussions about this there are now numerous people who have applied this with success. And as to the length of time "the solution" will last: Some have said "so far so good", others have said two years and most - with the advent of internet communication - seem to be the more recent affected that are thus far doing ok. I obviously know all the above because my own brand new 27PT5441/37 Phillips from Circuit City who muscled me out of buying a repair contract went "dark" right at the end of the usual 60 day warranty!! Now I know why it was sucha deal!! And why C.C. talked me out of buying the contract that I find despot on their part since denying me a contract gives away the fact that they've had complaints. Good luck and since at this moment I can't find the web site where I found "these angels" who tipped each other off I recommend you try to find it also using "phillips" as the key word.
Posted on Nov 02, 2006
I also purchased my Phillips 42in. from Circuit City, but they suggested for me to purchase the extended warranty contract. My now second plasma is in the shop under the extended warranty. The TV wouldn't turn on, just flashed seven times, pauses, then repeats. I'll ask the repair shop what the resolution was and then post it here. Hopefully they can't fix it and I'll get a new TV.
Posted on Sep 08, 2007
Would you like to sell this unit? If so for how much?
Posted on Nov 13, 2006
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