Philips plasma 50PF7320/10, display problem

[nikil511]

Hello everyone :-)
I have a Philips plasma screen, (50PF7320/10) with a display problem. (see images attached)

Everything else seems to be working fine, audio, tv reception, menus, etc.. it's only these horizontal lines that appear messed up in the screen.

I have read the repair manual (LC4.9E AA) and the training manual (PDP_2006)

I have a led flashing continuesly, on the SSB, and I can not get into SDM mode, via remote control using the 062596 code. Has anyone managed that ?

I dont see any bad caps, or other worn components. I wiggled the ribbon cables / connectors, with no effect.

Any help is really appreciated !

Thanks
Manolis

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

additional photos for references...

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

I moved to the SSB board, and found some suspicious bad? caps

Can someone give me his opinion ? photos attached

On image 6764 it seems some fluid from the caps has been spilled.

On image 6765 it seems to me that all caps have grown a bit :-) or their plastic cover seems a bit tight ?

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

I tried the customer services mode via the remote, and it worked. (image attached)

So the errors are:


(first detected error)
8 - Scaller eeprom I2C error while communicating with the scaller


11 - Columbus I2C error while communicating with 2d/3d combfilter columbus


(latest error)
16 - EPLD I2C error while communicating with EPLD

[PlainBill]

Re: Philips plasma 50PF7320/10, display problem

I'm suspicious of the main logic card (it's behind the small signal card), but I'm not real confident with that diagnosis. Perhaps Wizard will step in and give some help.

In the meantime, research the troubleshooting manual for the plasma panel. The plasma panel and support cards (sustain, buffers, power supply, etc) are from Samsung. Many of the main logic cards from Samsung have a test mode. Putting the panel into test mode would eliminate any chance the problem is due to the small signal board.

PlainBill

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

investigation continues

I checked the I2C line, and on the 3V3SW
I get 3.29V. So I assume voltage is ok for I2C

I dont have an oscilloscope with me here at this point, so I cant check if it is stable ...

Plainbill, thanks for the tip. Will look in to it.

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

I found on various service manuals that:
in order to Get Pattern to be Full White
(place jumper CN2012 on Logic Board).

however when I do, nothing changes... TV works as normal (menu etc..)

Do I also need to put something special in the "compair" plug ?

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

I have a new symptom.
TV turns off after a few seconds...
I get to see some picture, change a few channels, but after a few secs (5 to 10 seconds) it turns off.

blinking led on main board, (indicating data is flowing) turns off, also small SMD led on PSU turns off (i think it's called protection led ?)

For the time that the picture is on, I have the same visual problem as when started.

I did the following test, removed all AUDIO related connectors, and screen does not turn off. Visual problem remains the same, but not the screen does not turn off after a few sec.


Put audio back, to confirm, and yes it turns off after a few secs.

Conclusion:
Some voltage is on the "limit" ?
Will do more voltage tests.

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

I managed to enter the SDM mode, starting up with the related jumper shorted.

However, I can not switch to SAM mode.
When I press the volume down and channel down, it appers like its "crashing" or something. some unreadable chars / pixels ? appear on screen, no menu.

The thing I noticed is that the SDM text is "shaking" ... so I took a video, which you can see on this link:

http://www.youtube.com/watch?v=0EG686Gvj30

maybe to the eye of an experienced, it might ring a bell!

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

By the way, I have added all above photos, in original high-res in flickr

http://www.flickr.com/photos/9612414...7625358889519/

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

Ok.... after playing around with the TV I have "created" new symptoms, more clear this time! So I will try to summarize them:

1) Attempt to use TV as normal, all boards connected => Front Green LED blinking, no picture, ( I am in SDM mode hence there errors are 16, 11, 8 as seen on screen when it was working)

2) Attempt to start PSU with NOTHING ON => Alert LED on PSU blinking 13 times (12V problem)

3) Attempt to start TV with only picture boards (no audio, no signal board) => Alert LED on PSU blinking 4 times (3V3 problem)

4) Attempt to start TV with only picture boards (no audio, no signal board) and "white-picture" jumper shorted on main board => PSU alert LED blinks 13 times

(And this is the most interesting one)
5) Attempt to start TV with all picture boards, no audio, however with signal board connected only to PSU and not to main board - and main board white jumper shorted.

I have a white picture !!!
This white picture has the black horizontal lines ( initial symptom of tv)
I noticed now that the bottom lines are purple instead of black
While is not consistent, bottom corner is pink-ish


Also, D3V3 line on PSU goes from 3.2volt to 3.4v .. not stable!
and 12v line is 11.9 and using the "12v trimmer" on the PSU I can not get it to go any higher. If I turn the trimmer to the right, psu turns of with LED blinking 13 times, before actually increasing the 11.9v


Conclusion?
I definitely have "some" problems with the PSU .. I was thinking to replaces ALL CAPS larger then 100mf
Does that make sense ?
Should I replaces specific voltage regulators as well ?


Regarding the screen. When I do manage to get the white screen, can the black lines be justified due to faulty PSU ? or is this a different problem ? hence once I sort the PSU, I will have to replace main board or Y-circuit ?

Video with white screen: http://www.youtube.com/watch?v=iRfd033WtnU

[cadiman]

Re: Philips plasma 50PF7320/10, display problem

You have a y drive buffer out. for starters. If I remember that is a two part buffer (upper and lower) I have unplugged the bad buffer board and then the y drive would stay up and running and the power supply would stay on

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

..but, I also definitely have faulty PSU as well..
any change the "problematic electricity waveforms" are making some other components not working properly, and once the PSU is fixed, then the y drive will work ?

Y circuit, 3 boards (2 buffers and one main)
it could be on the main .. or on the buffers, or both ?

I need to track the problem to at least one board, before I go ordering replacements!

[mbates14]

Re: Philips plasma 50PF7320/10, display problem

bad Y buffers. if they intermittently short, they will shutdown the power supply or blow the sustain board.

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

ok, so can the Y buffers be repaired ? are there any common-failing components that I should check ?

[PlainBill]

Re: Philips plasma 50PF7320/10, display problem

ok, so can the Y buffers be repaired ? are there any common-failing components that I should check ?

Yeah. The ICs on the buffers are known to fail. This blog discusses the problems with the buffer ICs used in the 42" version of this TV. As far as I know, the same ICs are used on the 50" set you have.

PlainBill

[epod]

Re: Philips plasma 50PF7320/10, display problem

hi got the same tv green light but no picture three clicks when powered on but nothing im not getting no red flashing light on the front but one green on the in side any help please xmas soon need tv grrrrrrrrrrr

[nikil511]

Re: Philips plasma 50PF7320/10, display problem

Hello epod,
The led flashes I am talking about are on the PSU circuit, which you can see only if open the back of the TV.

Start from there, and I will help you diagnose the problems as much as I can (I'm no expert)

If you search around, you will find the service manual with the "led" codes etc.. (I'm in the office now, if you cant find it, let me know, I'll send you mine once I go home)

Manolis

[epod]

Re: Philips plasma 50PF7320/10, display problem

hi nikil 511 thanks for reply yes the light i see is coming from in side if i unplug the bootom plug that goes to logic board the two green lights stay on 8002 8001 but if i plug it back in they go out and i get a 4 flash code the code means d3v3 but i dont now what that is thanks

[PlainBill]

Re: Philips plasma 50PF7320/10, display problem

hi nikil 511 thanks for reply yes the light i see is coming from in side if i unplug the bootom plug that goes to logic board the two green lights stay on 8002 8001 but if i plug it back in they go out and i get a 4 flash code the code means d3v3 but i dont now what that is thanks

The service manual is here. 3.3V is produced on the Small Signal board. If this set uses the same DC/DC converter as the /37 version, the failure is well documented, and relatively easy to repair (three SMD ICs), total cost under $10.00.

PlainBill