Philips 42" Plasma - Model 42PF7320A

[Injustice]

You guys seem to be doing some great work on this site. Keep it up.

I just need some Good Advice on how to proceed with Properly Identifying the problems associated with this Plasma TV.

I have little experience with these matters and no equipment to test, sorry.
I opened it up looked at the Boards and none of them look like they are burned / no smell either.

There was some work done to this TV last year.
I changed the sound board - due to the loss of audio and
A local tech fixed a power issue by soldering some caps and putting in some heat sinks - to help with the overheating. That was another cost by itself.

tomm66, said :
"Yes - bad X-main, replace the X-main. Post a thread if you need more help." and
"Looking at the picture, it also looks like the Y-buffer may be bad, but the X-main is causing the discolouring too."

based on his evaluation of the photo, I am prepared to purchase these boards and replace them myself.
I am thinking this however, seeing that I am already in there - shouldn't I change out all the other boards too. I don't want to go back in there in a hurry

I have all the numbers for the following boards :

Y-buffer lower -
Y-buffer upper
X-Main
Y-Main

From reading other posts, changing one board alone might not do the trick and seeing that I have to send to the USA to get these parts - maybe I can save some time and money while at it.

I was alarmed when I saw the thick Black horizontal bar - thought it was the screen that failed. Why is it in 2 parts and not one continuous solid line ?
How will I know when the screen fails ?

My final question is : Are there any other issues that I might have to consider in completing the repair of this TV ?

Thanks in advance.

[tom66]

Re: Philips 42" Plasma - Model 42PF7320A

The X-main fails on these sets fairly often. When it fails, the gas in the panel doesn't fully discharge -- it almost looks as if the panel is broken, but it isn't. The gas isn't completely even, so some parts discharge and others don't when the X-main isn't providing enough energy for the panel to fully discharge. If the panel were broken, you'd see no image at all and instead hear a loud buzzing sound from the glass.

As far as repairs go, I'd highly suggest you replace the X-main first. The Y-buffers can be replaced after replacing the X-main if distortion is still an issue.

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

What brand should I buy ? Samsung or Phillips ?

The Original in the TV now, is Samsung but when I bought the Sound Card last year, I got Phillips - which is working well.

Logic states to go with Philips vs the Samsung Brand that failed.

Is there a difference ? Do you have preferences in these brands ?

[tom66]

Re: Philips 42" Plasma - Model 42PF7320A

Who made the plasma panel in this set? Order boards from that. They may be marked as Philips boards, but they are most likely made by Samsung.

[tibimakai]

Re: Philips 42" Plasma - Model 42PF7320A

I would just replace the upper and lower Y boards. The bottom chip still looks OK.
I have started on these TVs, I still have a bunch of these Y buffer chips on hand.

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

Who made the plasma panel in this set? Order boards from that. They may be marked as Philips boards, but they are most likely made by Samsung.

Just checked, Made by Samsung.
and that answers my question :P

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

I would just replace the upper and lower Y boards. The bottom chip still looks OK.
I have started on these TVs, I still have a bunch of these Y buffer chips on hand.

Ordered both the upper and lower Y-buffer boards and the X-main, just to be safe.

[tom66]

Re: Philips 42" Plasma - Model 42PF7320A

I'm pretty certain the X-main is at fault as well, you would not see the black part of panel with Y-buffer fault.

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

X-axis is horizontal and Y-axis is vertical right ?
and I am having issues with both
the ''X" issue is more predominant and visible in my case,
the "Y" lines are there too, just not as visible.

[tom66]

Re: Philips 42" Plasma - Model 42PF7320A

X-main is common vertical, Y-main is scan vertical. It is a little strange, the X-main would be more accurately called a Z-main (LG use Z-sustain) or common driver. It has nothing, at all, to do with the columns.

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

Ok, got the parts and did the following :

Changed the X main board - but there was no difference in the display
left the X-main in and then changed both the Y- buffers - this caused the screen to turn totally red and began flashing in 1 second pulses.

I did notice however when changing the X main, that of the 3 ribbons on the right that connects the screen with the board :
The Top one was OK ie. the gold band was in tact - mostly

The Middle one was lacking some gold on the band

The Bottom was in a bad state - about 50% on the gold on the band was missing - interspersed across the band.

It looks that it was consumed - missing parts for proper connectivity to occur.

Please tell me, your thoughts ...

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

Anyone wish to take a stab at this ...

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

Anyone wish to take a stab at this ...

tom66

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

Re-posting

Ok, got the parts and did the following :

Changed the X main board - but there was no difference in the display
left the X-main in and then changed both the Y- buffers - this caused the screen to turn totally red and began flashing in 1 second pulses.

I did notice however when changing the X main, that of the 3 ribbons on the right that connects the screen with the board :
The Top one was OK ie. the gold band was in tact - mostly

The Middle one was lacking some gold on the band

The Bottom was in a bad state - about 50% on the gold on the band was missing - interspersed across the band.

It looks that it was consumed - missing parts for proper connectivity to occur.

Please tell me your thoughts ...

[tom66]

Re: Philips 42" Plasma - Model 42PF7320A

Can we see a picture of the corrosion/deterioration?

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

working on them now

see attached now

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

done

[tom66]

Re: Philips 42" Plasma - Model 42PF7320A

You should just be able to clean those with isoproypl alcohol. So you saw -no- change in picture after replacing the X-main and Y-buffer?

[Injustice]

Re: Philips 42" Plasma - Model 42PF7320A

No change after replacing the X main. which was changed 1st.
After changing the Y buffers - the screen turned Bright red and started flashing / blinking, "like a turn signal"

[tom66]

Re: Philips 42" Plasma - Model 42PF7320A

With the original Y buffers in place, does it still flash?

I think your new X-main is defective though I did go through a similar process with another member on this forum -- three X-main later we determined it was a cracked resistor on the control board, the resistor was responsible for sending an important signal to the X-main causing identical symptoms to X-main fault.

Do you have any access to a digital voltmeter, or an oscilloscope?