Pink sparklies and voltage - Panasonic P42UT30B

[jonnyapps]

Hi all and thanks for this excellent resource.

My Panasonic P42UT30B plasma from 2011 developed increasing amounts of pink sparklies over the last year or so. Following some advice on here and elsewhere I experimented with adjusting the VSUS. However, I don't have a multimeter. I will get one but in the meantime thought I'd ask here to see if I've put the TV in any kind of danger with what I've done.

Here are the sparklies:


In light blue is the position these two potentiometers were in when I opened the TV up. Pink is the position I've had to move both to in order to eradicate the sparklies. They were moved counter-clockwise, towards a number 1 on the PCB and away from a number 3. This has been done in combination with setting VSUS to 'high' in the service menu.



Can anyone advise if this is safe or do I need to get a multimeter to check what's changed? There's no sticker that I can find that states the voltage settings inside the TV.

Thanks for your time.

[tom66]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Just do it from the service menu only. Tweaking the pots is a bad idea, you should reset them to default and keep VSUS at HIGH unless you have no other option. The TV should adjust VSUS as set ages.

• Power TV on.
  
• Hold VOL- on TV
  
• Press "0" three times on remote control
  
• Wait about 10 seconds...service menu appears
  
• Press GREEN button repeatedly to move through options until you reach VSUS.
  
• Press OK. Screen goes white.
  
• Press VOL+ to set VSUS HIGH, VOL- to set VSUS LOW. The screen brightness is very slightly (few %) brighter on HIGH VSUS (this is down to the gas in the panel...the panel is less efficient under higher VSUS but still produces a bit more light)
  
• Press "5" to show menu again. Verify option is set to HIGH. Press OK to save.
  
• Test panel on test patterns; use green and red buttons to move between these. (Press green until first pattern appears.) Most important ones to test are black, white, and dark red/green/blue colours, as these can maldischarge under high mode.
  
• To exit service menu, power off TV at wall socket. Do not change any other settings or you may "brick" your TV.

It's important that you save VSUS setting, as otherwise, it will go away when you exit service menu.

[jonnyapps]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Thank you very much for the detailed response.

I have followed your guidance. Unfortunately when I return those POTS to their original position and set VSUS to high in the menu as you instruct the pink static returns.

[*]Press OK. Screen goes white.

This whole screen is pinkish for me

[tom66]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Can you give us some data...

) Hours on the set. To view: Enter service menu as detailed before. Enter SRV TOOL by pressing red button once, then "OK". Move cursor to the right hand box that is one off from the bottom longer box. Hold mute for three seconds, and the hour and cycle count will appear. (Don't ask me why it's so obscure...I've no idea.)

) Measure Vsus and Vda using a multimeter. There should be test points. Caution: High voltage. Do not touch the probe location or any exposed high voltage parts.

) Measure Vscn and -Vad on the SC board (150V +/-5V and -190 to -210V approximately). Same caution applies.

) Measure Ve on the SS board (I think about 170V, but am not sure for this panel). Same caution applies.

My set has 9,000 hours on it, and no pinking. I did have some maldischarge/sparklies in "black" on the high setting, which I had the panel set at for a while because it was marginally brighter. That was before I realised I was being an idiot for about 1-2% extra brightness. Not only was the TV using more power, but it was applying more stress to the panel and the driver boards. It was only a bedroom TV, but I ended up setting it back to low and the issue with the maldischarge went away after a few days, so I figure the panel "bedded in" back to the original performance, which is good.

I've seen a similar U30B with 20000 hours on it with a still perfect panel. Odd fault, if any. I'd be leaning towards an issue with the PSU - maybe the Vsus output is too low. I can't see why else it would be pinking at this age. As PDPs age, they shouldn't go pink, they tend to go dark, with the centre of the panel effectively "dying", due to MgO ion impact damage (effectively the phosphor coating gets damaged by the extreme plasma inside the panel cells.) This only happens after 60k+ hours though, which is years and years of viewing normal TV, and can even be restored for at least a few years with much higher Vsus, at the expense of rapidly shortening the panel and driver board lifespan.

If you don't have a multimeter, one like this from Maplin will do; http://www.maplin.co.uk/p/uni-t-ut33...ltimeter-n60ec ... It ain't perfect, but for a £5 multimeter, you can't really complain.

[Moreno83]

Re: Pink sparklies and voltage - Panasonic P42UT30B

You definitely need a multimeter to control these values. A slight change is already 3 to 4 volts which is a lot!! Tom's way is good also but if you DONT see any significant changes when you alter the potmeter then there is probably a problem elsewhere.

The correct setting is 209V or 215V for the y-sus , one of these sets from 2011 is different , not sure if this is the set that has 209V.

This tv has the Ysus+buffers in 1 board. I would start with just tighten the screws and see if it changes anything. It can be that the screws are loose which is a 90% chance with these 2011 sets. The loose screws are arching which can give these symptoms.

Could you please check if the screws are tightened?

[Moreno83]

Re: Pink sparklies and voltage - Panasonic P42UT30B

The screws are maybe a long shot but if the voltage is correct ( 209 or 215v ) then you probably have a bad panel.

How about the mainboard Tom? Can the mainboard give false data to the sc board which results in sparkles? ( SC20 cable ).


Ps . when you use the potmeter on these 2011 sets and you alter it to much the tv will shut down ( protection ). Ofcourse you can damage it but it will shut down because it senses a error ....so you are "safe".

[tom66]

Re: Pink sparklies and voltage - Panasonic P42UT30B

The screws are maybe a long shot but if the voltage is correct ( 209 or 215v ) then you probably have a bad panel.

Not a bad panel unless it has some serious hours on it or is low on gas due to a bleed in the glass. I don't see that happening really. Exceptionally rare in fact.

It's funny because these PDPs are some of the most stable... I'd say they're almost as stable as the PZ80 panels in 2008 sets. The 2009/2010 Panasonic sets had various issues with black level rise over time to compensate for panel aging but these ones are pristine, with no black rise and virtually no maldischarge except from dead cold (which disappears within 20 seconds so it hardly counts.)

So I'm kind of baffled as to what has caused this fault but I am thinking it may well be the power supply in this case unless it really is a dud panel (which would be a first for any Panasonic PDP I've seen.)

How about the mainboard Tom? Can the mainboard give false data to the sc board which results in sparkles? ( SC20 cable ).

It's not data over SC20 cable..it's actual drive signals. The A board drives each of the transistors on the SC and SS boards to generate the various panel signals.
I've seen a Pioneer kuro 9G panel that had an ER value that was incorrect in the service menu and that was causing pinking of the panel. But only on some images. Not on full white, oddly enough. That was only because the previous owner had fiddled with the wrong settings whilst trying to remove red tint.

Ps . when you use the potmeter on these 2011 sets and you alter it to much the tv will shut down ( protection ). Ofcourse you can damage it but it will shut down because it senses a error ....so you are "safe".

Within reason. Running the set at a Vsus of 220-230V will probably eventually kill it.
Power dissipation in PDP scan driver rises massively when Vsus is much above the nominal rating, because the discharge current and ER are no longer aligned correctly. (Resonance point changes.)
Very high Vsus can crack the panel, but only due to heat. Not going to happen with anything a normal TV can do.

[Moreno83]

Re: Pink sparklies and voltage - Panasonic P42UT30B

True , but luckily the voltage on this set won't go lower then 199 and higher then +/-213V. ( If vsus is 209v )
Vsus is normally written on the panel sticker.......

I have seen plasma tv's that had sparkles because of the arching problem....got worse and worse and then shut down with the 7 blink error. I also saw some threads where people said the image on the tv got worse and shut down with a big bang.

Its good to check the screws anyway!

[tom66]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Yes, seconded checking the screws, known issue. Good that you brought it up.
Do that before any of the other checks I mentioned.

[Moreno83]

Re: Pink sparklies and voltage - Panasonic P42UT30B

The potmeter has silicone on it so im pretty sure the voltage would have been a relative stable voltage. ( 209.5/208.5 ) etc.

I have this power supply so if you want to know the exact voltages , i can always measure them.

[jonnyapps]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Wow. Thanks for all of the responses. A lot for me to digest. I've never attempted anything with a TV before so this will take me some time to get my head around.

Will head to Maplin tomorrow morning and take it from there once I've bought the meter.

Will answer all points raised tomorrow.

Thanks again.

[Moreno83]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Before you do anything , just tighten the screws all ALL boards. You will see that they are loose.

Multimeter , DC range , Black prope on chassis and red on Vsus.

[tom66]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Remove the screws (one by one, don't remove ALL the screws from a board) and check them for signs of burning or arcing. If they are burnt/damaged, you will need a new screw kit which I believe you can get from eBay.

[tvtimmy]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Scrape off any carbon or black stuff on the screw holes too.

[jonnyapps]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Remove the screws (one by one, don't remove ALL the screws from a board) and check them for signs of burning or arcing. If they are burnt/damaged, you will need a new screw kit which I believe you can get from eBay.

Just to double check - you're literally just referring to the screws that mount the boards to the chassis?

[tom66]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Just to double check - you're literally just referring to the screws that mount the boards to the chassis?

Yep.

These Panasonic sets use a newer design (that was later adopted by other manufacturers) which uses the actual chassis of the TV to form the ground plane of the board.

If that's missing, or poorly connected (high impedance as engineers would say), parts of the circuit can start malfunctioning. A design error occurred where the screws were not quite torqued correctly during the assembly process, and over time they worked themselves free due to thermal expansion, which caused some arcing and intermittent contacts.

It's certainly worth checking these to see whether they could be the fault. Even if they aren't, if they show signs of burning I'd replace them anyway, just to prolong the life of the TV.

[jonnyapps]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Can you give us some data...

) Hours on the set. To view: Enter service menu as detailed before. Enter SRV TOOL by pressing red button once, then "OK". Move cursor to the right hand box that is one off from the bottom longer box. Hold mute for three seconds, and the hour and cycle count will appear. (Don't ask me why it's so obscure...I've no idea.)

OK, so I've been out of town unexpectedly for a few days. Apologies for the delay and thanks again for all the detailed responses.

The set has been used for 11,324 hours and on/off'ed 3817 times.
There were two screws half a turn loose but tightening them didn't change anything. I shall check each one shortly.

) Measure Vsus and Vda using a multimeter. There should be test points. Caution: High voltage. Do not touch the probe location or any exposed high voltage parts.

) Measure Vscn and -Vad on the SC board (150V +/-5V and -190 to -210V approximately). Same caution applies.

) Measure Ve on the SS board (I think about 170V, but am not sure for this panel). Same caution applies.

Now for confession time. I have no idea how to do this. I've looked at the service manual but that's just confused me more as I'm not too knowledgeable with electronics. I'm more than willing to try but would need to be told exactly where to test. I appreciate this is asking a bit much so feel free to tell me to go get it serviced! I can provide photos of the boards if required.

Here's another pink sparklies image for good measure:


Thanks again.

[chrismurphy]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Just increase VS voltage until red sparkles go away
Dont use service menu

[Moreno83]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Now for confession time. I have no idea how to do this. I've looked at the service manual but that's just confused me more as I'm not too knowledgeable with electronics. I'm more than willing to try but would need to be told exactly where to test. I appreciate this is asking a bit much so feel free to tell me to go get it serviced! I can provide photos of the boards if required.

Here's another pink sparklies image for good measure:


Thanks again.

Ok first things first. What TV settings are you using? Could you please set the tv back to its factory settings and see if it changes anything?
If you have done that and there is no improvement then it is best to remove the sc board from the tv. To much backlight or contrast can give sparkles.

Step 1 is to TURN OFF TV!! and remove the blue/white cable that is coming from the powersupply going to the SC board and remove the SC20 cable. ( Small white flat cable ) and then remove all the screws on the SC board.

Step 2 is to gently flip the SC board on its side , make sure the orange flat cables are not damaged. ( Put something under the sc board so it does not give any pressure on the orange flat cables. ).

Step 3 is to get a solder iron so you can reflow the solder pads on the back of the board. ( It will have black resideu ). You can also gently scrape the black resideu off so in the end it will make good contact with the chassis.

Step 4 is to reinstall the board back in the TV and tighten the screws on ALL boards including the boards on the bottom , all screws will be loose.

Step5 is to put your meter in DC range. Put the black prope on the chassis , a good point is 1 of the small holes from the tv footstand. ( in chassis ). Put the red prope on one of the cables going to the SC board ( top pin out of my head... ).

Step 6 is to turn on the tv and immediately read the value on your meter. It will start somewhere around 207V and it will jump to 215V. It can be that the correct Vsus for this model is 209V instead of 215V. Its either 209 or 215V.

Step 7 is to figure out if the vsus is matching the above. If not then you can apply more or less voltage to the SC board. You can use the potmeter on the powersupply. First make sure you put the potmeter back in its ORIGINAL spot. Use the sillicon for guidance. Measure again and please write down what you are measuring. You only need to alter the potmeter for Vsus , the other one can damage your panel.

Step 8 is to use a tiny screwdriver and GENTLY alter the potmeter. A slight change is already 3 to 5v which is ALOT. To much voltage will give sparkles and less voltage also. Take 209 or 215V for "perfect setting".

If you still dont see any changes you might have a bad mainboard or panel.


So please come back with the values you are measuring and what Tom66 said. You can find it on the SCBOARD on the bottom side , it's a resistor that shows VDA/VCE written next to it in yellow.

I will take pictures when i get home for guidance.

[tom66]

Re: Pink sparklies and voltage - Panasonic P42UT30B

Use the highest voltage range for your meter (usually 500, 600 or 1000V DC). Make sure to use DC, not AC mode.

Vsus can be measured at TPVSUS on the power board.

The SN board (large green board on the left hand side when looking from the back) has the Vad and Vscn voltages.

You test them on the points TPVAD, TPVSCAN with red probe on those points and black on the chassis.

The Vda voltage should be available on a small connector on the power supply, or thereabouts, maybe on a point marked TPVAD. Generally in the 55 to 65V range (often 58V on modern Panasonic PDP).

Be very careful not to slip the probes or touch high voltage parts. It may help to have the ground lead put in a screw hole (I find the stand bracket part works quite well).