Philips 42PF9630A/37 horizontal lines

[mrosenberg42]

Re: Philips 42PF9630A/37 horizontal lines

Even with the cover off after a couple of hours it starts to show the lines, but if I cool it down with a fan the lines cease until I turn the fan off and it heats back up.

I will swap the logic boards between the two and see if the boards make a change with the swap.

[shovenose]

Re: Philips 42PF9630A/37 horizontal lines

alright then, add a small quiet fan to a voltage rail somehwere 5-13v and have it cool it...

[PlainBill]

Re: Philips 42PF9630A/37 horizontal lines

alright then, add a small quiet fan to a voltage rail somehwere 5-13v and have it cool it...

Not a good idea. Normally these sets work well without cooling. Adding a cooling fan masks what may be a trivial problem. It's possible that the actual cause is the main logic board. Cooling the buffer will work only so long until it fails, taking out the Y-Sustain. Spending $5.00 for a cooling fan to avoid replacing a $50 main logic card sounds good until you have to replace the Y buffers, Y-sustain, AND main logic card at a total price of over $250.

Some Plasma TVs are notorious for inadequate cooling. Some of the Vizios using a 50" LG panel is one example. Those can benefit from cooling fans.

PlainBill

[Tvbob]

Re: Philips 42PF9630A/37 horizontal lines

Excessive heat on any device is caused by one of two things.
The device is being turned on too long.
The device is driving an excessive load.
buy a board.

[mrosenberg42]

Re: Philips 42PF9630A/37 horizontal lines

Excessive heat on any device is caused by one of two things.
The device is being turned on too long.
The device is driving an excessive load.
buy a board.

I agree. I guess where I am confused is what is causing the buffer to be driven in excess. A problem in the Y - sus or the logic board? And also why the lower buffer board is not seeing that same excessive load?

[PlainBill]

Re: Philips 42PF9630A/37 horizontal lines

I agree. I guess where I am confused is what is causing the buffer to be driven in excess. A problem in the Y - sus or the logic board? And also why the lower buffer board is not seeing that same excessive load?

I'll be honest with you. I've seen a number of manuals that include 'Theory of plasma displays' tutorials. I have never seen enough of a schematic that I can translate that theory into what is actually happening in the main control card, X, Y, and Z sustain cards, and the buffers. Heck, at one time I was looking for a data sheet for the buffer IC itself and came up blank.

I THINK that the sustain card outputs a voltage and an address for each horizontal element on the display. The buffer decodes that address and routes the signal to the appropriate line. Or maybe the main logic board supplies the address and the digital value for the voltage. One VERY tentative theory suggests that if a particular buffer is turned on too frequently (due to a bad address line) it would overheat.

The puzzle gets worse when you think about the plasma panel itself. Thy Y-buffers drive 768 lines that run the width of the panel. I'm not sure if it's even possible, but if there was leakage between adjacent lines, that would certainly cause additional stress on the buffers.

There are a lot of mysteries. Heck, I don't even know what would happen if you unplugged one of the cables that link the panel to the buffer. Now IF that were safe, and IF you did it, and IF the buffer still got hot, that would indicate the problem is NOT the panel. Of course, if you tried that and several buffer ICs started venting smoke while the sustain shot flames across the room, you would know that was a REALLY bad idea.

PlainBill

[mrosenberg42]

Re: Philips 42PF9630A/37 horizontal lines

Check out Coppell TV repairs latest blog about these particular buffer boards. He says "horizontal line or lines of pink / red sparkles is clearly a buffer on its way out". Which is exactly what my set has going on.

So now the million dollar question: Is the buffer board I just bought good or bad? It seems to work fine till it heats up. Which seems to be an indication of buffer chips going bad.

If I wasn't worried about throwing money away I would order a new logic board and go from there, but these plasma sets just aren't worth a whole lot these days.

I have read so many threads on this exact problem and they all lead back to the buffer boards. Dilemma. Dilemma.

[PlainBill]

Re: Philips 42PF9630A/37 horizontal lines

Check out Coppell TV repairs latest blog about these particular buffer boards. He says "horizontal line or lines of pink / red sparkles is clearly a buffer on its way out". Which is exactly what my set has going on.

So now the million dollar question: Is the buffer board I just bought good or bad? It seems to work fine till it heats up. Which seems to be an indication of buffer chips going bad.

If I wasn't worried about throwing money away I would order a new logic board and go from there, but these plasma sets just aren't worth a whole lot these days.

I have read so many threads on this exact problem and they all lead back to the buffer boards. Dilemma. Dilemma.

What is the history of the buffer board you purchased? If it was 'Removed from TV that had a broken screen, as is', that's how I would sell my marginal or bad boards if I didn't have any ethics. If it was a rebuilt board, but didn't carry a warranty...

I understand what you are saying about the value of plasma TVs. When anyone can buy a new 42" plasma TV for $500, and a new 30" for $700, it's kind of hard to get $400 for a 4 year old set.

PlainBill

[mrosenberg42]

Re: Philips 42PF9630A/37 horizontal lines

The buffer board was purchased brand new from a reputable company. This is actually the second one they sent me because the first had a dead buffer chip which showed up as a black band in the screen.

This second board I assumed to be new as well but doesn't have the normal heatsinks that I have always seen on these boards. So this one could be rebuilt. The original purchase had a 90 day warranty so I should be covered. It's been about 3 weeks since the original purchase.

[mrosenberg42]

Re: Philips 42PF9630A/37 horizontal lines

Quick update on the progress of these Plasma's.

I decided to take the good buffer boards and put them in the set that also had the horizontal lines across the whole picture to see if it would exhibit the same issue I was seeing on the other TV.

Happy to say that after replacing the buffer boards the picture has not exhibited any of the problems the other set was having. But Damn this plasma produces some heat.

Since I have a USB port on the TV I was thinking of adding a USB fan to pull some of that heat out of the chassis. Does a USB fan sound like a good idea or would tapping into a 12v rail somewhere be a better scenario?

I am a little worried that pulling from an existing 12v rail might cause problems. Whereas the USB port is a dedicated 5v.

I found an 80mm Thermaltake USB fan with speed control that looks like a good candidate.

[PlainBill]

Re: Philips 42PF9630A/37 horizontal lines

Quick update on the progress of these Plasma's.

I decided to take the good buffer boards and put them in the set that also had the horizontal lines across the whole picture to see if it would exhibit the same issue I was seeing on the other TV.

Happy to say that after replacing the buffer boards the picture has not exhibited any of the problems the other set was having. But Damn this plasma produces some heat.

Since I have a USB port on the TV I was thinking of adding a USB fan to pull some of that heat out of the chassis. Does a USB fan sound like a good idea or would tapping into a 12v rail somewhere be a better scenario?

I am a little worried that pulling from an existing 12v rail might cause problems. Whereas the USB port is a dedicated 5v.

I found an 80mm Thermaltake USB fan with speed control that looks like a good candidate.

Over a year ago I purchased a slightly older version of this set. I replaced the bad caps. The TV was 'confiscated' by my wife and moved into her office where is sees about 40 hours of use per week. We have seen no further problems. Yes, they generate a lot of heat. But notice the set is designed to use a chimney effect to draw cool air in at the bottom and vent it out the top.

Don't waste your time.

PlainBill

[2canchew]

Re: Philips 42PF9630A/37 horizontal lines

I have a 42 inch Philips 42PFL7704D/F7 and i get distorted lines ever now and then when the credits at the end of a show start displaying or other word show up . but only where the words are and all the way across the screen .This does not happen all the time but is happening more often. these are horizontal. Would appreciate any advise

[tom66]

Re: Philips 42PF9630A/37 horizontal lines

Perhaps the buffers are being damaged by a bad logic card?

On one TV I repaired you would get horizontal lines on the whole screen if the any of the Y row connectors were disconnected. Every other line was not being lit up, like an interlaced pattern.

[Essenar]

Re: Philips 42PF9630A/37 horizontal lines

I'm sorry to resurface an old thread, but I have this exact TV with this exact problem. The TV was donated to me by a school-mate and I plan on replacing the upper board AND logic board. Any advice on where I can get these parts? Also, would replacing the caps on the boards also remedy the issue if I take them to an electrician?