42PFL7422D/37 Service Manual Needed

[Panama]

Re: 42PFL7422D/37 Service Manual Needed

Update on my 42PFL7432D/37.

The no light - no image problem returned after a few days so I tried the trick suggested by selldoor of heating the large capacitor (see red box in picture) with a hair dryer before startup. It solved the problem so I ordered the replacement cap until they got the proper one and I soldered it in.

Unfortunately the problem has not changed. If I heat the new capicitor with a hair dryer, it starts up fine, otherwise no image. Hmmm.

Any thought / advice would be apprceiated.
Thx

[selldoor]

Re: 42PFL7422D/37 Service Manual Needed

OK If heating the area works it suggests a cold solder joint
Re solder all the joints inside the red area except the green ones.

If you examine with a magnifier you may find a cracked one in which case do that first

[Panama]

Re: 42PFL7422D/37 Service Manual Needed

Ok. I was not able to remove the old solder - 25 Watt iron didn't produce enough heat to let me suck it up. but I held it on each connection until it was liquid and added a bit more solder, but no excessive amounts. Some of the connections did look suspect before and they all joints look good now. But I've got nothing now, even with the heatgun to the cap - on one try.

So I suspect I'm onto a problem here. Do you think I need to pick up a 40W or 60W iron to do this job properly? and do I need to suck up the old solder then resolder each connection?

[Panama]

Re: 42PFL7422D/37 Service Manual Needed

2nd time around resolding the connections outlined in the diagram -was able to suck the majority of the old solder and do what I think is a good resoldering. but still no resolution of the problem. Heating cap and that area of the board now does not work. I'm baffled.

[selldoor]

Re: 42PFL7422D/37 Service Manual Needed

Hi- when I said try heating theBig Black cap it was in the context of the
Lelon cap on the other board.

Anyway something did work however briefly- we just need to find what.
Does the sound work?
Does the dim unlit picture still come on.
Power Board:
With it all connected and on can you test the voltages on the connectors from the secondary side NOT the ones to the lights. Cant actually see a tagged ground screw so use the ground on the top left connector.(in your picture)
If all the voltages are not present, on the MAIN Board bottom Left there is a red fuse. With the power OFF for 5 minutes can you check it. Meter on ohms 200 - should read the same as touching the probes together.
Post result.
If that is ok with it all switched on Meter on 600vDC CAREFULLY measure the voltage at the fuse.
Also on that board a little way up between the ywo white connectors at the bottom there is a white rectangular component at 3004 and another that looks the same a little to the right - is there any marking on these.?

[Panama]

Re: 42PFL7422D/37 Service Manual Needed

Hi Selldoor
The sound works, but the ghost image no longer presents and the backlight does not lite anymore. I did try to preheat the Black Lelon cap with no effect. Same for the new main power supply cap.

On the secondary side connector I got the following readings
BL-DIM - 0.0V
PO - 0.0V
BL-ON - 0.02 V
GND - 0V
NC - 0.0V
PSON - 4.07 V
5.2VSS - 5.08 V
12V - could not contact with DMM.

Both the Main Power supply fuse and the Red fuse on the SSB did check out for continuity, however I could not get a voltage reading on either w DMM setting on either 1000VDC or 200VDC.

The small components on the SSB labelled 3004 and 3D3 were both marked with 100.

Now the set has gone into error code mode (6-3), but I will try to get the fuse readings a bit later.

[TheJudge]

Re: 42PFL7422D/37 Service Manual Needed

Afternoon gents,

Seems the Philips curse has hit me as well. I have zero electrical engineering background but found this thread to be incredibly informative and am hoping to have similar success. Just a few hours on the message board has given me a new found respect for the level of knowledge and complexity of this profession.

My model is the PHILIPS 52PFL7422D/37 Chasis 0523.1U LA. I'm operating under the assumption that many of these boards are similar to the aforementioned 42" in question. Current status of unit...solid blue light indicating power with green lights #1, #2 and #5 lit. Backlight seems to be working from what I can see through the rear holes. Inverters (of which there are 4) master and slave sides look to be in decent shape. Possibly replaced since it was a refurb buy from '08. The only thing that has stuck out to me is on the main power board, the large yellow "capacitors" (not sure if that's correct) seem to have a little discoloration which can be seen in the photos. My apologies in advance for picture quality but it is all I have to work with. Very curious if I should simply change out the main supply board or inverters as well? Backlight working, and actually came on for about 10 minutes last night but simply goes out with blue light staying lit. Also, the unit has been in a screen in porch out of the elements for the most part but does have a layer of dust on components. Is there a better solution or cleaning agent to wipe off the affected areas? TIA!

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

Has anyone worked on one of thest Philips 42PFL7422D/37 LCD TV's yet?

I got one yesterday. It has sound but no picture. The guy I bought it from stated that this failed the same exact way before. A tech came to his house and swapped a board out it worked for a year then the same problem again, except now the warranty is gone. I have only been researching so far cause I'm stuck at work overnight - woohoo!!!. I have seen where some people have replaced master inverter boards or slave inverter boards. I have to do some testing to see which is bad. What's the chances one of you guys can find a service manual for this? I hate swapping boards and I'd like go to component level.

Pics of boards to come - as soon as I can get home and get sleep.

As a nubie to this forum, I'n not sure this is the correct way to post. I have a Phillips 42PFL7422D/37, Chasssis # Q523.1ULA. Upon powering up the picture will flash on for about 500ms and the screen goes black, but I have sound. When I press menu the menu screen shows up and I can change any setting. However when going to the setting assistant the screen goes black again. Assuming that it is a small signal issue I ordered the SSB board. Am waiting for delivery. Is this an issue with the SSB or something deeper.

[Dgtech]

Re: 42PFL7422D/37 Service Manual Needed

Sounds like an interesting failure. I would probably pursue this problem the exact same way. I wouldn't be able to single out any one component that will cause that.

Of course, I hope you already read through the known failures with this set in this thread and tried everything already right??? Of course pictures would help too.

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

Yes I have read many of the posts and checked all of the boards for overheating, capacitor swelling and the rest. I have many years of experience with semiconductor test equipment, final test etc. so I know what to look for. I will post pictures soon. The SSB board is due in soon, I'll update you when it arrives.

[Dgtech]

Re: 42PFL7422D/37 Service Manual Needed

There's really no need to post pics if you are electronics qualified unless there was something you were unfamiliar with. You seem to be on the right track.

[budm]

Re: 42PFL7422D/37 Service Manual Needed

@dmanning7. Do your boards look like this on this thead:
https://www.badcaps.net/forum/showthread.php?t=24458
It is also Phillips 42PFL7422D/37, Chasssis # Q523.1ULA.
The one in this thread does not have the same board.
Service manual:

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

Neither of the manuals match the set I have. Mine has the inverter boards on either side of the chassis. However the wiring block diagram shows the inverters.

[tibimakai]

Re: 42PFL7422D/37 Service Manual Needed

I would also check if there is a newer firmware, maybe it helps.

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

Been there, done that.

[budm]

Re: 42PFL7422D/37 Service Manual Needed

It will be best then for you to post good clear pictures of the boards for us to see.

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

Here is a picture of the boards.

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

got the new ssb board, installed it, programmed the option no's. Got the same result as with the old board. I can see the menu and the back light is on, but when I try to do the setup assistant, the screen goes black, but with a flashlight I can see the images. What next. By the way I did not see the service manual that matches my tv.

[mobohacker]

Re: 42PFL7422D/37 Service Manual Needed

Just a follow-up post for anyone who needs the information. I purchased a DPS-168EP board for $60 and replaced it. It immediately fixed the problem.

I have this same version of the 42PFL7422D/37 as this old post from last year. This is a TV without the ambilight with a build date of 2008. No master/slave inverter boards. Instead just the one DPS-168EP power board with two pairs of white wires going to jacks at the LCD panel edges. Symptoms were the same - sound but no video after turning the TV on (no light on the screen at all). Turning the TV on and off several times would eventually make it work.

Just wanted to report that I replaced the DPS-168EP board (now $114 in December of 2012) and it did fix the problem. I can't see anything visibly burned on the old board. It looks like that large transformer is acting like a fluorescent ballast transformer for the cold cathode fluourecent tube(s) that light the LCD.

Fluorescent ballasts arcing internally are a major failure item for building lighting with T8 and T12 tubes, so I imagine the same is true here. The ballast transformer is probably starting to short/arc internally. In TVs they often have shutdown circuits if something in the high voltage section starts pulling too much current. I'm guessing that when that transformer arcs on startup a shutdown circuit somewhere keeps the inverter off.

The audio circuitry is on the video board. From the schematic in the manual for the chassis I see that video board has its own power supply fed directly from the AC power input, hence the sound but no picture symptom.

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

There is not a board in my tv that resembles the DPS-168EP. Look at the picture on my previous post.