Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

[Avilla1985]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

hi i have a panasonic TH-42PX60U, which works fine when first plug in for about 10mins, then shuts off no power and no standby light, it has a tnpa3911 power supply, any ideas on what the fault could be

thanks
aaron

[zacksiga]

Re: Panasonic TH-42PX60U Plasma 7 Blinks

Hi,
I have a Panasonice TH-42PX60U with 7 red blinking lights. I believe I know the problem, but I just want to confirm it with you guys. What I have done so far; I have disconnected the SC20 on the SC board to test to see if the SS board was working, and then I turn on the TV, and it turn on with no picture. The SS Green led light on the board lit. So then I connected the SC20 back and disconnected the SD, SU board from SC board to test to see if it is the SC board. Turn the tv back on and the TV turn on, both the SC and SS green LED lit on their boards. Then I just put back the SU board to see if only the SD was bad, turn the TV on and I get 7 blinking light. Reverse it and did the same with the SD, and I still get the 7 blinking light again. So I think its the SU and SD board are bad, but I am not 100% sure. So I am here to confirm my diagnostic. Can anyone tell me if both my SU and SD board are bad, and that what I should change. Sorry about my previous post with grammar.

[zacksiga]

Panasonic TH-42PX60U Plasma 7 Blinks

Hi,
I have Panasonice TH-42PX60U with 7 red Blinking lights. I believe I know the problem, but I just want to confirm it with you guys. What I done so far; I disconnected the SC20 on the SC board to test if the SS board was working, and the TV turn on with no picture, and the SS Green led lit. So then I connected the SC20 back and disconnected the SD, SU board from SC board to test to see if it is the SC board. Turn the tv back on and the TV turn on, both the SC and SS green LED lit on their board. Then I just both back the SU board to see if only the SD, turn the TV on and I get 7 blinking light. Reverse and did the same the SD, and I still get the 7 blinking again. So I think it the SU and SD board are bad, but I am not 100% sure. So I am here to confirm my diagnostic. Can anyone tell if both my SU and SD board are bad, and that what I should change.

[tw2005]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

On which Board? SC or Main? I heard about removing some diode and shorting some pins on an IC for 7 Blinks and,
I read on one of the benches here from the previous owners that Also, removing 2 capacitors on the Power Supply for some Panasonics which use the TEAxxx IC. removing the capacitors disabled the IC and, it could not send the signal to the main to cause the 2 or 10 blinks. I have not yet tried but, I heard it works
There has to be some way to disable ALL of the SOS on the Panasonics. It seems that they will trigger for almost anything

SC, but I don't know of any way to disable all as each has it's own signal path.

What TV and what issue are you trying to isolate? Do you have a separate post on what you're working on?

I'm not that knowledgeable with those PSU models with the 2/10 blink fault on the modules in the PSU.

[electronicsurplus]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

On which Board? SC or Main? I heard about removing some diode and shorting some pins on an IC for 7 Blinks and,
I read on one of the benches here from the previous owners that Also, removing 2 capacitors on the Power Supply for some Panasonics which use the TEAxxx IC. removing the capacitors disabled the IC and, it could not send the signal to the main to cause the 2 or 10 blinks. I have not yet tried but, I heard it works
There has to be some way to disable ALL of the SOS on the Panasonics. It seems that they will trigger for almost anything

[tw2005]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Hello tw2005,

How exactly can the shutdown CCT be bypassed? is it the same for all Panasonic Plasma or, only this one? Thanks a bunch

WHich one? 7 blinks? on the 2009 Sc I think i removed a smd dual diode and cut a track on the the SOS7 path to SC20, but I think someone else has also simply earthed out the SOS7. may have been Tom but I've tried that too and is less intrusive.

I only tried it because I could get the TV to fire up occassionally so i knew it was not shorted Sc or buffers, just low voltage on the SC.

[electronicsurplus]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Hello tw2005,

How exactly can the shutdown CCT be bypassed? is it the same for all Panasonic Plasma or, only this one? Thanks a bunch

[electronicsurplus]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Does anybody know how to bypass the shutdown circuit in Panasonic Plasma? I read here a short while ago but, cannot find it anymore. It did seem fairly simple.

[allsmith]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

I pulled the PSU tonight to inspect for cold joints(jewlers loop),Didnt really see anything that looked bad but i did reflow a couple joints that looked a little funny.

I noticed that it looks like a fuse has been replaced before,(not sure what kind a fuse it is)

I cleaned and cycled the VSUS pot again.

I pulled the heat sink that covers the 450v caps to get a better look(they both seem to have a slight bulge to them compaired to all the rest)

I noticed a little bit of arc burn on the pins that the two big wires from the sc board hook at the PSU( cleaned that up and put a tiny amount of contact cleaner on the pins and made sure i seated them good on reinstall)

Other thing i noticed is where the mains plug,plugs into the back of tv into that filter unit is very a loose connection, it sure aint very tight when you plug the cable into it.

Put tv back together and it still shut off on me within a couple hrs( whole screen goes dim first)

Do you know what kind of fuse this is,or maybe why it has been replaced?

I think i read about the AC line filters could go bad(Is this a possibility?)

[allsmith]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Sorry,have had some other projects going on last few days and have not had time to work on the tv any(but i have been watcing it every night)

Seems it is shutting off a bit more often here lately.

Tonight it has shut off three times in a row.For a while tonight when the VSUS started dropping, i turned down the picture and brightness control and the voltage would go back up to normal.(but not everytime though)

Next couple days im gonna pull the power supply and inspect for cold joints and get a cap list for it,(I think its worth a shot if them bigger caps are not too expensive.)

Check VAD voltage and see if it drops right before tv shutts off

Im gonna clean that VSUS pot one more time with contact clearner while i have the psu board out.

Dont know if this helps as a clue or not ,but i contacted the original owner of tv and they said it started shutting off about a year ago and that it started turning off more and more often until they bought a new tv(but they kept using it pretty much until a month ago or so)

Do you all think i should pull and look for cold joints on the SC board this weekend when i have the PSU out also?

If after ''If i find no cold joints'' what would you all do first?

#1 replace the sc board( its ony 50 at jimmy and i can return if its not the problem)

#2 Recap the PSU( should i go with the the original Nichicon caps or go Panisonic caps?)

#3 Replace one or both SU/SD board?

Is the question here (Is something pulling down the VSUS voltage,or is the psu not providing enough?

I got a couple more pics of what it looks like "most" of time just before it shut off ( it doesnt always start looking funky at top of screen first,but only sometimes)

Most times the whole screen goes dims pretty much evenly.

Got any more ideas? Thanks All

[tom66]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

It's the large ones at 1400uF 200-250V each that provide Vsus.

[allsmith]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

You have tried the cleaning trick? Maybe try inspecting the board for cold joints. Does Vda vary, too?

Yes i cleaned the pot with very good contact cleaner(but i was thinking about doing it one more time,just to be sure)

I have not tested Vda yet,(not sure how to do that ,but i'll look it up in the service manual)

Yeah i was thinking about pulling the psu and inspecting for cold joints.

Im gonna be putting in a cap order for my philips,Think i ought to replace that one cap i think looks domed compaired to the rest, just for giggles,since thats something I(noobie) can do?Also its the only thing i would know to do before replacing boards

I believe the cap i think is domed is on the primary side of the psu(but im not positive of that)

Can you tell by looking on the psu what caps control the 193v section(sorry im just i noobie thinking out loud)

Thanks Tom

[tom66]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

You have tried the cleaning trick? Maybe try inspecting the board for cold joints. Does Vda vary, too?

[allsmith]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

I tried serviceman mode/aging,and the tv has shut down everytime while scrolling through the different colors.(have done it 3 times,i can get tv to shut off within about 10 min or less sometimes)

white and green seem to trigger it to start dropping the voltage.

I watched the DMM and it will be steady, then every now and then just drop to 180v, but then go back to 193v

But eventually it start to go below 180v and drop more to around 150v then the tv will shut down.

The whole picture does start to go dim all at once(not the top half first)
almost like all of the center of the screen goes first with some color left around the outer perimeter.

[tw2005]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Can't hurt just make sure those high voltage caps are not still holding High voltage if you only just turned the set off. Been caught out myself not checking them and it hurts.

I only have limited experience and the only voltage drop issue I had with 7 blinks was a bad VAD on the SC but Toms PSU idea is plausible. It's all tie in really because the sos7 detects bad voltages on the SC and I guess if the PSU was kind of working and went low it probably would trip the SOS7.

It's a bit like my current 4blink issue on another Panasonic which is meant to be a PSU SOS. The PSU is good but the SC has shorted out the VSUS making the PSU think it's at fault.

[tw2005]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Try service mode, sect 9.3.1. I think in option,aging you can go full white,red,green, blue,black. You may be able to set the pattern to white in there. On mine in automatically changes through the different ones automatically every3 secs but I just tried it out quickly without my manual . Mine is a 2009 model.

[allsmith]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Unless it has been fiddled with you would not need a scope but in the manual it does tell you what adjustments need to be set if any depending what boards are replaced. Any voltages reglated by the SC board should be checked and I believe thats after the correct voltages supplied to it from the psu are set correctly first.
Section 10.3 in the manual.
SC Board adjustment after exchange Vad TPVAD (SC) -105V ± 1V VR6600 (SC).

When I did my SC on the Panasonic it was bang on, no adjustment but that was from Shopjimmy and out of a new TV with damaged screen so wouldhave been already adjusted for voltage.

It's a tough one to give good advice on. For all we know it may be the PSU or bad solder joints. It's strange how it drops but then somehow recovers itself.

If i order any boards they will be from shopjimmy.

I have not had any boards out of this tv yet,think i should pull the PSU and look for cold joints maybe?

[tw2005]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Out of the half dozen times ive actually "seen'' it shut off ,It seems it can do 3 different things, 1 it can shut off pretty much all of a sudden, 2 the screen will start to get funky and dim then shut off,and 3 i saw its voltage start dropping ,the screen gets funky,but then pulls out of it and the voltage goes back to normal without shutting off.

But yeah it does seem to not like a lot off white,the voltage usually drops about .5v on bright scenes when its acting correctly.

The service manual does says to ''input'' a white scene when setting VSUS,dont know if there is a whitewash feature,I been trying to think of a dvd that would have a lot of white going on to watch to test with,but cant think of anything besides hooking up my laptop through svideo and putting a white background up.

If i was to get a new sc board,would it have to be calibrated with a Oscope?
Or would it be plug and play?

Unless it has been fiddled with you would not need a scope but in the manual it does tell you what adjustments need to be set if any depending what boards are replaced. Any voltages reglated by the SC board should be checked and I believe thats after the correct voltages supplied to it from the psu are set correctly first.
Section 10.3 in the manual.
SC Board adjustment after exchange Vad TPVAD (SC) -105V ± 1V VR6600 (SC).

When I did my SC on the Panasonic it was bang on, no adjustment but that was from Shopjimmy and out of a new TV with damaged screen so wouldhave been already adjusted for voltage.

It's a tough one to give good advice on. For all we know it may be the PSU or bad solder joints. It's strange how it drops but then somehow recovers itself.

[allsmith]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

Out of the half dozen times ive actually "seen'' it shut off ,It seems it can do 3 different things, 1 it can shut off pretty much all of a sudden, 2 the screen will start to get funky and dim then shut off,and 3 i saw its voltage start dropping ,the screen gets funky,but then pulls out of it and the voltage goes back to normal without shutting off.

But yeah it does seem to not like a lot off white,the voltage usually drops about .5v on bright scenes when its acting correctly.

The service manual does says to ''input'' a white scene when setting VSUS,dont know if there is a whitewash feature,I been trying to think of a dvd that would have a lot of white going on to watch to test with,but cant think of anything besides hooking up my laptop through svideo and putting a white background up.

If i was to get a new sc board,would it have to be calibrated with a Oscope?
Or would it be plug and play?

[tw2005]

Re: Panasonic TH-42PX60U Plasma Turning Off Occasionally 7 Blinks

My theory behind the buffer board is if the set does not turn off purely on either then we should be able to assume the buffers are good and concentrate on either the PSU as you've suggested or the SC board.

I think the other thing here is what was said about the infomercials, mainly white.

The PSU,SC,SD & SU boards would be working hardest on a full white display. I know they state to set the TV to white for the adjustments.

Maybe it might be a good idea to go into the service menu and set the test pattern to white or maybe there is a white wash feature. It would be interesting to see how long the TV runs if at all under full load.

It may help speed up the fault finding. Certainly an intersting fault, so many variables.