Panasonic TH-42PX80U won't turn on - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 25 Old 07-11-2010, 09:38 PM - Thread Starter
Newbie
 
bandit1965's Avatar
 
Join Date: Jul 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hello All

I have a Panasonic TH-42PX80U, used it last night, everything was fine. Today, I go to turn it on and nothing. I cannot turn it on with the remote or by pushing the button. Wall plug in has the cable box plugged into it and it works so that can't be the problem. I disconnected the power cable and reconnected, nothing changed. Any ideas or am I just missing something obvious, thanks.
bandit1965 is offline  
Sponsored Links
Advertisement
 
post #2 of 25 Old 07-12-2010, 09:12 AM
AVS Special Member
 
tomwil's Avatar
 
Join Date: Feb 2008
Posts: 1,382
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
You have to be perfectly sure you are getting power to the TV. I would unplug the cable box and plug in the TV in the same receptacle to eliminate any chance of receptacle problems.

Also, be sure the power cable is fully plugged into the TV. It should snap into place.

If that doesn't change anything, then try to determine if you hear relay clicks when you plug in the TV. The TV should give at least 2 clicks when plugged in, one click immediately, and another click about 15 seconds later.

If no clicking is heard, then suspect internal problems, possibly a blown fuse on the power supply.

Here are two manuals to help you diagnose and repair the problem:

Panasonic TH-42PX80U Service Manual
Panasonic TH-42PX80U Technical Guide

Good luck!

That which may be known of God is evident within man, for God has shown it to them, so that they are without excuse. (Romans 1:19-20)
tomwil is offline  
post #3 of 25 Old 07-12-2010, 04:04 PM - Thread Starter
Newbie
 
bandit1965's Avatar
 
Join Date: Jul 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Thanks for the quick reply. I will try the plug in and listen for the clicks. If it is internal, is this fuse something I can change myself? I will post my findings.
bandit1965 is offline  
post #4 of 25 Old 07-15-2010, 11:26 PM - Thread Starter
Newbie
 
bandit1965's Avatar
 
Join Date: Jul 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I tried unplugging and plugging it in, I heard no clicking noise. The plug in works for other electrical equipment, so I don't think that is the problem. What's next?
bandit1965 is offline  
post #5 of 25 Old 07-16-2010, 06:11 AM
AVS Special Member
 
tomwil's Avatar
 
Join Date: Feb 2008
Posts: 1,382
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
From the service manual page 14, it says to check the fuses F401, F402, F403, PR401, and PR601 on the power supply P-board.



You can use the diagram on pages 74 and 76 to locate the fuses. F401 and F402 are located near power connector P9, highlighted by the red square, and should be checked/replaced first.


That which may be known of God is evident within man, for God has shown it to them, so that they are without excuse. (Romans 1:19-20)
tomwil is offline  
post #6 of 25 Old 07-23-2010, 10:48 PM - Thread Starter
Newbie
 
bandit1965's Avatar
 
Join Date: Jul 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Where can I buy these fuses and are they easy to replace once found?
bandit1965 is offline  
post #7 of 25 Old 07-24-2010, 05:12 AM
AVS Special Member
 
tomwil's Avatar
 
Join Date: Feb 2008
Posts: 1,382
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
The fuse part numbers are in the service manual, and if you cannot find them locally you can order online at partstore.com.

If you have little experience in testing/replacing fuses, it might be best to buy another P-board off eBay or partstore, or have your set serviced by a repair shop.

That which may be known of God is evident within man, for God has shown it to them, so that they are without excuse. (Romans 1:19-20)
tomwil is offline  
post #8 of 25 Old 11-28-2010, 01:15 PM
Newbie
 
Soybom's Avatar
 
Join Date: Nov 2010
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Thank you for your help. Both fuses F401 and F402 are blown. Where are F403, PR401, and PR601 located?
Soybom is offline  
post #9 of 25 Old 02-27-2011, 06:41 PM
Member
 
Cobra Commander's Avatar
 
Join Date: May 2007
Posts: 31
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Soybom View Post
Thank you for your help. Both fuses F401 and F402 are blown. Where are F403, PR401, and PR601 located?
So you found F401 & F402, as shown in the prior screenshot, within the Red Rectangle.

F403 is a similar-looking fuse (mine did NOT have the red stripe like F401 & F402) but in the screenshot, is hidden under an aluminum(?) shield. If you note the P12 callout out, and run a line straight down to the bottom of the photo F403 is at the 'bottom' of that shield below P12.

PR601 & PR401 threw me way off too, I had to eyeball the PDF for a while and found them. They're an atypical fuse (in my newbie experience) - as they look like what I would've assumed was a capacitor - but a reddish-brown color with orange text. NO clue how to multimeter those puppies. Well, maybe if their soldering points were accessible from the 'foil side' (underside) of this P-Board?

NOTE: Intention is not to bump, but to supplement one of the only decent troubleshooting threads of this popular Panny.
Cobra Commander is offline  
post #10 of 25 Old 02-28-2011, 04:14 AM
Member
 
DavidOH's Avatar
 
Join Date: Sep 2006
Posts: 183
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Lots of info here.

http://www.avsforum.com/avs-vb/showthread.php?t=1001318
DavidOH is offline  
post #11 of 25 Old 02-24-2012, 04:56 PM
Newbie
 
ledvedder's Avatar
 
Join Date: Feb 2012
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Did you ever get this problem fixed? I'm having the same issue. How would I go about testing the fuses?
ledvedder is offline  
post #12 of 25 Old 03-23-2012, 02:33 AM
Newbie
 
brenthen's Avatar
 
Join Date: Mar 2012
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
hi i have the same issue was going now dead but mine is model TH-42PV7AZ do the examples shown in this post still apply also did you find out what was the cause of the fuse blowing
brenthen is offline  
post #13 of 25 Old 03-23-2012, 08:22 AM
AVS Special Member
 
tomwil's Avatar
 
Join Date: Feb 2008
Posts: 1,382
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
Regarding the Panasonic TH-xxPX80U models:

Researching info from an expired eBay auction, it appears that if fuses F401 and/or F402 continually blows out on the power supply P-board, it is usually because the Q406 FET transistor has shorted out.

The replacement for Q406 appears to be generic RJK5020.


That which may be known of God is evident within man, for God has shown it to them, so that they are without excuse. (Romans 1:19-20)
tomwil is offline  
post #14 of 25 Old 04-13-2012, 03:58 PM
Newbie
 
kjak's Avatar
 
Join Date: Apr 2012
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Soybom View Post

Thank you for your help. Both fuses F401 and F402 are blown. Where are F403, PR401, and PR601 located?

How do you remove and change these fuses? It doesn't appear that they just pull out.
kjak is offline  
post #15 of 25 Old 04-14-2012, 05:34 AM
Member
 
DavidOH's Avatar
 
Join Date: Sep 2006
Posts: 183
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
You will have to use a soldering iron.
DavidOH is offline  
post #16 of 25 Old 04-14-2012, 07:39 AM
Newbie
 
kjak's Avatar
 
Join Date: Apr 2012
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Ok, thank you.
kjak is offline  
post #17 of 25 Old 04-28-2012, 04:03 PM
Newbie
 
jimbokimb's Avatar
 
Join Date: Apr 2012
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Hello, so mine just went too - no warning, and no lights flashing at all. I broke it all down and tested the fuses I get a reading of 2-8 on my multimeter. Does that mean they are blown? Also I found the other one (under the metal shield) that which gives me about the same reading 2-8.

Wanting to know if those need three need to be changed. Or what is going on? I'm a bit lost...please help me out. Maybe someone out there had this fixed?

Thank you.
jimbokimb is offline  
post #18 of 25 Old 02-08-2013, 05:31 AM
Member
 
ou8one2's Avatar
 
Join Date: May 2003
Location: Philadelphia
Posts: 89
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by tomwil View Post

Regarding the Panasonic TH-xxPX80U models:


Researching info from an expired eBay auction, it appears that if fuses F401 and/or F402 continually blows out on the power supply P-board, it is usually because the Q406 FET transistor has shorted out.


The replacement for Q406 appears to be generic RJK5020.



Thanks for this info and sorry for pulling an old thread but maybe someone else could benefit from it. My Panny died about a month ago and I found this thread. I pulled Q406 and tested it. It was shorted. However, Q406 was a RJK5010. I was able to order it for $12 and the fuses are made by Little Fuse. Replaced all and my Panny is now working. Thank you!!!

Here are links to where I bought the parts from.

http://www.audiolabga.com/mal_cart/mal_cart.php?find=rjk5010

http://www.littelfuse.com/products/fuses/axial-radial-thru-hole-fuses/5x20mm-fuses/215sp/0215008_mxespp.aspx

You can get the fuses from Mouser, Digikey, etc.

John
ou8one2 is offline  
post #19 of 25 Old 02-13-2013, 12:27 PM
AVS Special Member
 
tomwil's Avatar
 
Join Date: Feb 2008
Posts: 1,382
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 22
John, Thanks for letting us know of your success.

There is a new excellent video on YouTube, showing how to diagnose and replace the Q406 FET.



That which may be known of God is evident within man, for God has shown it to them, so that they are without excuse. (Romans 1:19-20)
tomwil is offline  
post #20 of 25 Old 02-20-2013, 05:10 AM
Member
 
ou8one2's Avatar
 
Join Date: May 2003
Location: Philadelphia
Posts: 89
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Tom,

Nice video. I wish I would have found that first. I called several places for a replacement and they couldn't find a cross reference for it. I even called RENESAS, because they are the manufacturer of that FET, and they couldn't tell me what the replacement was and that they would have to get back to me. That never happened mad.gif So I finally stumbled on the part from the first link. So repairing my Panny for $20 some dollars was nice, eventhough I paid more for shipping biggrin.gif

I didn't replace those diodes because they checked out okay!! So hopefully they don't die out on me anytime soon!!

Thanks for taking the time to make those videos for us people that don't won't to take it to you for repair biggrin.gif

John
ou8one2 is offline  
post #21 of 25 Old 06-23-2013, 04:25 AM
Newbie
 
geoffrey53's Avatar
 
Join Date: Jun 2013
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I hope this may prove useful and possibly save a repair bill. I own a Panasonic TX-P42X50B tv and on two occasions have experienced power outages/cuts resulting in complete power loss with no indication of 'life'. Assuming something had blown and no obvious access bile fuses to replace we arranged for a repair.

However prior to the repair date and having left the tv without power, all cables disconnected. I tried one more time and hey presto we have full working set. The time period is a little hard to gauge for leaving the tv powerless but my best guess would be 48hours.

I can just imagine tv repair firms rubbing their collective hands with glee when this model comes into the shop. "yes pickl it up in two days sir, it will be all fixed no problem" and they just leave it on the shelf gathering dust

Atb

Geoff
geoffrey53 is offline  
post #22 of 25 Old 07-06-2013, 12:51 PM
Newbie
 
deandome2's Avatar
 
Join Date: May 2011
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Sorry. I'm kinda new to multimeters (but a really good solderer, due to my RC car hobby).

How do I test the fuses? what do I set the meter to (ohms? what "level"?) Does it matter what side I put the red & black probes on? What do I look for to know if it's blown or OK? While I'm at at...same question for the MOSFET?

The video is great, but you can't see what how the dial of his meter is set up.

Thanks!
;
deandome2 is offline  
post #23 of 25 Old 07-14-2013, 10:25 AM
Newbie
 
deandome2's Avatar
 
Join Date: May 2011
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I have a TC-P42S2 that's totally dead; no LED flashes, no clicks...just nothing. I tested the fuses, they were OK, but I'm not sure if I tested the MOSFET properly or not.

But given how cheap the used boards are on ebay, I bought one from a well-rated seller w/lots of recent history. I put it in...still totally dead. So my question is, is there a simple test to tell if THIS board is the culprit, or maybe is another one bad, too?

I wast thinking that the leads coming off this board...the ones with 2 or 3 bigger wires (vs. the 2 multi-pin connectors) should have some DC power flowing thru them....so if those leads are dead, it HAS to be that the new board is as dead as my original one.

Does that make sense? I don't want to keep replacing boards, of course, but I don't want to give up on the set quite yet.

Also, what's the proper way to test the Q406 MOSFET? I watched the video on this thread, but it's kind of hard to see which of the 3 leads on the MOSFET he's touching. It looks like the black-wire probe is on the middle wire & the red one's on the 'top' one....is that correct? and does the 3rd wire do anything?

t
deandome2 is offline  
post #24 of 25 Old 07-15-2013, 07:09 PM
Newbie
 
advocates's Avatar
 
Join Date: Jul 2013
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I have looked at a lot of forums and consumer reviews and this is the only model that seems to have many cases of this problem. I have seen isolated cases in older models and one on a newer 58" model, but I don't think I saw any problems on a 50".dqdpMGcool.gif
advocates is offline  
post #25 of 25 Old 11-29-2013, 03:48 PM
Newbie
 
mohamed abdulal's Avatar
 
Join Date: Nov 2013
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10

I have tv

panasonic plasma tv

th-p42x50m

The first was when the power off after 6 or 7 or even 10 hours working again And then turned to change my electricity capacitors Oatguet it idle But then did not work and now do not have any image Aydaúh not only works Allamadh green Bstmrar that operates without the screen Possible that followed me how it works've landed in the screen or what is the solution

pls talling me how can i fix this or tall me how i can make the resat the tv

send me by emial : mohamed.abdulall@gmail.com

mohamed abdulal is offline  
Reply Plasma Flat Panel Displays

Tags
Panasonic Th 42px80u
Gear in this thread

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off