42PFL7422D/37 Service Manual Needed

[mobohacker]

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.

Hi - I should have worded that better. I wasn't replying to your post, but rather just general info related to that post I quoted from last year. For anybody else who may have my version of the set with the same problem. The same thing that fixed that set last year with the CPS-168EP board fixed mine.

As for your problem, I just read through your posts, and if it were me I would try replacing the master/slave inverter boards as a set. I had that set in my hands. Before I had opened up my set I bought the board pair just based on what I had read here on the forum about the inverter chip and the 4 mosfets on those boards being high failure items. Then took the back off and discovered mine had no inverter boards. Sent them back and got the DPS board. That master/slave board set was $60. From a time perspective I figured that for just $60 I couldn't justify the time investment to troubleshoot the thing myself, especially given the fine pitch surface mount chips.

Good luck!

[dmanning7]

Re: 42PFL7422D/37 Service Manual Needed

Got the master/slave inverter boards, installed them and still have the problem. What I need is a schematic of the power supply to check for voltages etc.

[PhilipsKSI]

Re: 42PFL7422D/37 Service Manual Needed

I have this model (Philips 42PFL7422D/37) and here's what the issue is:

When I turn on the unit with channel set to tuner like channel 3 for Cablebox, it turns on for a second and then goes black but sound remains on and power LED remains on.

When I turn on unit with HDMI input selected, it works fine although I can see a couple of backlights are out when picture is bright. If I power up (cold start) unit in any of HDMI selected modes, I can then switch to channel 3 and it works there as well but not vice-verse.

So it has to be cold started up in non-tuner mode to work otherwise, screen is black.

Any suggestions? And what do you call the screwdriver that's needed to open the back of this unit?

[johnboy1313]

Re: 42PFL7422D/37 Service Manual Needed

I have this model (Philips 42PFL7422D/37) and here's what the issue is:

When I turn on the unit with channel set to tuner like channel 3 for Cablebox, it turns on for a second and then goes black but sound remains on and power LED remains on.

When I turn on unit with HDMI input selected, it works fine although I can see a couple of backlights are out when picture is bright. If I power up (cold start) unit in any of HDMI selected modes, I can then switch to channel 3 and it works there as well but not vice-verse.

So it has to be cold started up in non-tuner mode to work otherwise, screen is black.

Any suggestions? And what do you call the screwdriver that's needed to open the back of this unit?

All I can help with is the screwdriver bit. It's called a torx bit. I wanna say it's a T10 bit, but I may be wrong. It's been a while since I opened one of those up.

[PhilipsKSI]

Re: 42PFL7422D/37 Service Manual Needed

All I can help with is the screwdriver bit. It's called a torx bit. I wanna say it's a T10 bit, but I may be wrong. It's been a while since I opened one of those up.

It is a T10 for most of the screws. I tried to open it but there are two screws that are behind this plate at the bottom and cannot be accessed with a T10 screwdriver. Also there seem to be some screws that aren't T10 on top and I'm not sure if they also need to be removed but regardless it didn't open after removing the accessible T10 screws.

[LEDWill]

Re: 42PFL7422D/37 Service Manual Needed

Hi all,

This thread is great. I have a Philips 42PFL7422D TV as well and am having similar issues to others on this thread. I'm new to TV repair, though I have a little background electronics. I do not have any test gear so it's making this difficult.

The main problem is that you turn the TV on, the blue power indicator light comes on and the screen flashes with the input bar "AV2" comes up and then the whole screen goes black after a couple seconds. I seem to be able to change the input on the TV, and I can hear audio, but the screen is totally black.

I opened the TV up and saw that the Master Inverter board had a bulging cap. I've looked close at all the boards and can't seem to find anything else visibly wrong. I replaced the bad cap, which did not fix the problem. I went ahead and replaced the other cap on the master inverter and the two caps on the slave inverter board. Still has the same issue. I'm not really sure what to do next. I don't really want to buy a new set of inverter boards since I'm not totally sure if the issue lies there.

Any help would be great. I'll attach some pictures. Please let me know if you need any further info. Thanks!

[Dgtech]

Re: 42PFL7422D/37 Service Manual Needed

Hi all,

This thread is great. I have a Philips 42PFL7422D TV as well and am having similar issues to others on this thread. I'm new to TV repair, though I have a little background electronics. I do not have any test gear so it's making this difficult.

The main problem is that you turn the TV on, the blue power indicator light comes on and the screen flashes with the input bar "AV2" comes up and then the whole screen goes black after a couple seconds. I seem to be able to change the input on the TV, and I can hear audio, but the screen is totally black.

I opened the TV up and saw that the Master Inverter board had a bulging cap. I've looked close at all the boards and can't seem to find anything else visibly wrong. I replaced the bad cap, which did not fix the problem. I went ahead and replaced the other cap on the master inverter and the two caps on the slave inverter board. Still has the same issue. I'm not really sure what to do next. I don't really want to buy a new set of inverter boards since I'm not totally sure if the issue lies there.

Any help would be great. I'll attach some pictures. Please let me know if you need any further info. Thanks!

I hate to say it but...without any test meter, that's the safest bet. Its a 75 percent chance that its an inverter problem. Id feel a lot better if you can prove it though. Borrow a meter maybe?

[-goodtimes-]

Re: 42PFL7422D/37 Service Manual Needed

Hello,

First off, to all the helpful posters, Thank you very much!

So, I have a PHILIPS 42PFL7422D/37. It went black. The symptoms were as follows;

-TV powered up, showed status for approximately 2 seconds (bar across the top of the screen showing "HDMI 1 on the left and the time on the right" then no picture and just sound.

-with a flashlight to the screen I could see the picture

-the blue power led was lit

My conclusion, due to research of the problem, was bad inverter boards. I ordered new inverter boards (master and slave set) and installed them. While I had the back of the TV open I carefully inspected all visible boards, components, and connections for any faults or damage and found all to be visibly good.

After reassembly I powered up the TV and viola! it came on as usual.....so it seemed at first. I very quickly noticed that the picture had a very slight (but very noticeable) flicker, especially noticeable when the picture was light (like on the menu screen). The flicker was definitely not there before the old boards went out. I checked all connections again, including power, HDMI, and all connections inside the TV. There is no change. The flicker is there no matter what is connected or not connected. With nothing but the power cord connected and TV on with a back lit screen you can still see the flicker. I did some more research and found very little information directly referring to this model. I did find a tidbit of info suggesting two different possible causes, one being the capacitors on the inverter boards are bad, and the other suggesting that I turn the contrast to 100 and the brightness to 50. I tried the contrast and at 97 the flicker disappeared. Is it possible that the NEW inverter boards have a bad capacitor or capacitors? I will attach a picture of the inverter boards that were originally in the TV, the replacement boards, and a picture of the label on the back of the TV showing the model of the TV.

The old/original boards are numbered 6632L-0470A and 6632L-0471A
The new boards are numbered 6632L-0501B and 6632L-0500B

I hope my post is not too long but I wanted to give as much information as possible.

Any help would be greatly appreciated.

[-goodtimes-]

Re: 42PFL7422D/37 Service Manual Needed

Also, I forgot to mention, the picture seems grainy. Not too long before the picture went out I had purchased the Disney WOW! calibration disc and had all of my settings dialed in (they really did not change much from the way I had them) and the picture was crystal clear and not grainy at all. I used several different discs and streamed videos of very familiar material to confirm it was not just the first thing I watched after the repair.

[Dgtech]

Re: 42PFL7422D/37 Service Manual Needed

I believe that the flicker you are seeing is from a dying CFL lamp, just as you would notice this in an office building lighting fixture with CFL tubes. Keeping the contrast lower is better for these sets anyway. When I used to have one, mine use to hum and produce a heated smell whenever the contrast was above about 80%. I sold my set since then. I got tired of replacing parts. Im sure GM or Ford made it - LOL.

[-goodtimes-]

Re: 42PFL7422D/37 Service Manual Needed

Ok, well thanks for the info and quick reply. I also just noticed a slight dim/dark line across the bottom of the screen.....about an inch from the very bottom. Are there any parts that I can replace or repair to fix the set? I am motivated and cannot afford a new set as of now. Is it probable that the new boards are faulty?

Thanks!

[Dgtech]

Re: 42PFL7422D/37 Service Manual Needed

How bad is the line? Pictures

[-goodtimes-]

Re: 42PFL7422D/37 Service Manual Needed

I will see if it shows up in a picture, but it was a soft darkened line about an inch up from the bottom of the screen and about 1-2 inches wide. Let me try and get a picture.

[-goodtimes-]

Re: 42PFL7422D/37 Service Manual Needed

Here is a picture.

[-goodtimes-]

Re: 42PFL7422D/37 Service Manual Needed

The discoloration/line goes away after 15-20 minutes. ???

[Dgtech]

Re: 42PFL7422D/37 Service Manual Needed

Sorry I didn't get back to you but with all the nice weather, I had to get lots of chores done.

At my job we have the normal fluorescent tubes in our ceiling light fixtures. From laziness, people keep replacing the bulbs knowing that it has a ballast problem. So the bulbs last just a little while and then they start flickering. Then soon they are out all together.
In your case this looks to me like the lower CFL bulb is going. It was probably going before the inverter went out. I had monitors like this. I confirmed my suspicions by taking it all the way apart to get to the bulbs and indeed they were about to fail completely. Dark on ends like the ceiling variety. Replacing the bulbs are somewhat difficult and the difficulty level varies from set to set. If the set is ran like this for a while, you may see it completely fail. Either the inverter again, or the lower half completely dark from the bulb's death.

My strategy would not be to fix this set any more than what it is already. I would sell it to a technician and try to get at least $80 for it. Put that money towards a new set since they are getting cheaper.

[-goodtimes-]

Re: 42PFL7422D/37 Service Manual Needed

Thanks, I think I will continue to try as I cannot afford a new tv at this time.

[LifeJoka82]

Re: 42PFL7422D/37 Service Manual Needed

I have a Panasonic 42PFL7422D/37 plasma TC-L42E50 tv that works but once I turn it on it has a strobe light effect. I took the tv apart and found that one of the 2 LCD circuit boards had a prong thing that was burnt. I have 2 questions: 1 how do I find the circuit board model number and 2 how do I take the circuit board off. If anyone has the answer please feel free to message me on here or email me joshua.daniels82@yahoo.com.

Thanks

[tom66]

Re: 42PFL7422D/37 Service Manual Needed

I have a Panasonic 42PFL7422D/37 plasma TC-L42E50 tv that works but once I turn it on it has a strobe light effect. I took the tv apart and found that one of the 2 LCD circuit boards had a prong thing that was burnt. I have 2 questions: 1 how do I find the circuit board model number and 2 how do I take the circuit board off. If anyone has the answer please feel free to message me on here or email me joshua.daniels82@yahoo.com.

Thanks

What TV do you have....

A Philips 42PFL7422D (CCFL backlit LCD TV aka LCD TV)
--OR--
A Panasonic TC-L42E50 (LED backlit LCD TV aka LED TV)

[polarbehr]

Re: 42PFL7422D/37 Service Manual Needed

Any ideas?