Is my Panasonic TC-P42X3 PS Bad?

[niswanger]

Hello,

Just getting around to troubleshooting my faulty Panasonic TC-P42X3. After a vacation this summer we came back and the unit wouldn't power on. The red power LED would blink 14 times. Did some searching...I tried checking for a short from chasis ground to pin 1 of P2 and it was a short, then I disconnected the cable to the other board and checked again and it was again a short. So this means it's the power supply board right? Again, P2 pin 1 to chasis ground was short with both the cable connected and disconnected.

So now that I have determined that and found that they are $100+ IF you can find them in stock, I thought I would try to troubleshoot at a component level and I need you all's help

I've attached some pictures. There are two fuses that I would like to check but I need to lift one lead correct? These fuses are weird in that they have seats that are soldered and make the fuse non-serviceable w/o desolder of one lead.

So let's start this chase I hope someone here can give me some guidance.

Thank you,
Roy

[freakaftr8]

Re: Is my Panasonic TC-P42X3 PS Bad?

Disconnect SC and ss boards. Short still present on power supply? If not connect one at a time then retest

[niswanger]

Re: Is my Panasonic TC-P42X3 PS Bad?

I checked P2 pin 1 to gnd and it was short, then I disconnected the SC board (other boards connected) and it was again a short. I followed this procedure for code 14 relevent to my model: https://youtu.be/iHBIiRxhe0w?t=1m42s Notice he said that if P2 pin 1 to gnd with SC board disconnected is a short then the PS is bad. Is this correct?

So I re-installed and started at top left P2 (connected and disconnected = short). Top right P11 (with P2 SC still disconnected and P11 DISCONNECTED = 300K ohms from P2 pin 1 to gnd). I'll stop here, thoughts?

Thank you,
Roy

[tw2005]

Re: Is my Panasonic TC-P42X3 PS Bad?

That suggest the SS is shorted. You have to watchout for some of these videos,they have a habit of being incomplete.

basically you're checking if Vsus is shorted. Vsus is supplied to both SC via P2 & SS via P11. they are the same voltage rail, so if the short clears when the SS is disconnected , that would be SS short, you could then just probe across the Vsus pins on the Ss and confirm short.

problem sometimes though is the SS can take out the Sc at the same time and if the Sc is damaged and you put in a new SS it then blows that.

This is a HD model, the video your using is for FHD models and the Sc and SS are not connected to each other like yours but the 14 blink can be triggered by shorted vsus

[niswanger]

Re: Is my Panasonic TC-P42X3 PS Bad?

Yea no kidding on the videos out there which is why I'm not going to play spend $$ to throw away. If I can't be 100% sure of the bad board and/or component then I will just walk away.

This video in the beginning said it's for a number of models and my model was listed so it goes to say then the step where he says that if SS connected or disconnected shows a short then it's the power supply is wrong. I do have some EE troubleshooting training (Nuke ET on a fast attack) it only makes sense (like having to lift a lead to test a component) that you must check for short with everything disconnected.

So the SS board is on on the right under the input board (looking from the TV from the rear with the top at 12 o-clock). I am at work now so will have to wait until I get home . I will need to take the input board (board with the A/V inputs) off to get to the SS board and then find Vsus pins. Now my guess is that it will be shorted so I will have to go from there and his video does show how to troubleshoot the SS.

Finally if I find the problem, then I will need to confirm that the SC is good or bad. Oh boy, why couldn't it just be a bad power supply?

Thanks,
Roy

[tw2005]

Re: Is my Panasonic TC-P42X3 PS Bad?

The SS11 should be the top connector so I'd expect you'll get to it or use the lead end. There's gnd, P15v and vsus on that top one( 3 connections)

SN could be fine but I'd probe SN2 and SN3 for shorts just in case and/or probe all the IGBTs for shorts just in case. i don't know the common fails on this one but on the 2010 models I have seen people go round in circles blowing up new boards because one or the other was bad too. Not an issue on the FHD models

[niswanger]

Re: Is my Panasonic TC-P42X3 PS Bad?

Yes P1 has from top to bottom 15Vc, GND and then Vsus. So good idea, just use that pig tail connection to test.

This model date is Feb. 2011 and again is the 1080P TC-P42X3

I'll post what I find when I get to it. Thanks for your help and freakaftr8's initial help.

-Roy

[tw2005]

Re: Is my Panasonic TC-P42X3 PS Bad?

Yes P1 has from top to bottom 15Vc, GND and then Vsus. So good idea, just use that pig tail connection to test.

This model date is Feb. 2011 and again is the 1080P TC-P42X3

I'll post what I find when I get to it. Thanks for your help and freakaftr8's initial help.

-Roy

How many versions of TC-P42X3 are there? As far as I know and what the panasonic manual states, 720p,1080i HD model.

If there's a cable running from SS3 to SN3, it's HD model

FHD model would be a U30, S30, ST30, GT30 etc

X is the start of the range which is HD 720p

VT SERIES
FHD Premium 3D
TC-P55VT30
TC-P65VT30

GT SERIES
FHD Deluxe
3D
TC-P50GT30
TC-P55GT30
TC-P60GT30
TC-P65GT30

ST SERIES
FHD Core
3D
TC-P42ST30
TC-P46ST30
TC-P50ST30
TC-P55ST30
TC-P60ST30
TC-P65ST30

S SERIES
FHD Leader
TC-P42S30
TC-P46S30
TC-P50S30
TC-P60S30

X SERIES
HD Leader
TC-P42X3
TC-P46X3
TC-P50X3

[freakaftr8]

Re: Is my Panasonic TC-P42X3 PS Bad?

Don't forget Z series. These were all the X series in 1080p definition.

[freakaftr8]

Re: Is my Panasonic TC-P42X3 PS Bad?

Roy. Just repaired a 50st30 model. Ss board failure 14 blinks. Check all mosfets on that board to center pin. Bet you have 2 or 3 shorted. Mine were the 30F131. Yours may be different. But these are known to short.

[niswanger]

Re: Is my Panasonic TC-P42X3 PS Bad?

Okay, I know I have a 720P model. I just checked P11 pig tail from the SS board (that's the one on the right side viewing from the panel from the back with the top at 12 o-clock) and the Vsus pin to ground (chasis) was a short. I checked P2 pig tail from the SC board (left side of panel) and it was in the meg-ohm range.

So it's a short somewheres on the right side of the panel. From the looks of it I need to unscrew the I/P board to access the whole SS board (it's a long board running along the right side of the panel (again from the perspective I mentioned above).

So I can check mosfets while on the board...just measure resistance from center lead to ground? *will be adding picture of the SS board soon to ask where to take measurements.

So I also attached closed ups of all the mosfets on the SS board. Notice the center lead is clipped, is this lead mounted on the other side? I need to determine the gate drain and source and check for short between the drain and source correct? Then I'll probably need to remove it and do a full test on the bench.

LOL, bear with me while I answer my own questions and update this post (for the benefit of others as well). I'm attaching the mosfet data sheet showing the gate, drain and source.

Okay, SS board testing components on-board Q101 and Q102 which are the RCJ450N20 MOSFETS with MM on diode check and positive lead to center leg "drain" and negative lead to the right leg "source" (legs facing my body) and there is no short. But for all 3 RJP30H2As, measuring the same it was shorted. These too are MOSFETS but I "think" they are N-Channel. Am I testing them correctly? Attached is an image with the 3 MOSFETS I "think" I measured to be bad.

Thanks,
Roy

[freakaftr8]

Re: Is my Panasonic TC-P42X3 PS Bad?

Yep they sound shorted to me. alas there's most likely your problem

[niswanger]

Re: Is my Panasonic TC-P42X3 PS Bad?

So I found a used board pulled from a working unit for about the same price as ordering these components. Again, testing like I did is correct for these 3 MOSFETS mounted, that is + lead on the center leg and - lead on the right leg which was a short. Do I have to confirm these MOSFETs are indeed bad by removing them and testing them out of ckt?

What's the likely hood of replacing the SS board and the SC board in my case causing the new SS board to go south?

Thanks,
Roy

[niswanger]

Re: Is my Panasonic TC-P42X3 PS Bad?

Alright, well I thought I was a detailed oriented person...attention to detail! Well, I'm not in this case. I found this for a great price so ordered it: http://www.ebay.com/itm/TNPA5313-Pan...vip=true&rt=nc

It came in and when I went to bench test the MOSFETS all were good but thought it was odd that it had one extra mosfet (see attached images). Then after I installed the board the two large panel ribbon cables didn't line up to the board connectors. Both boards have TNPA5313 printed on the CKT board but the white bar code sticker on the original says 5313AC and the replacement says 5313.

Also, the mosfets on the new board in the same locations as the ones on the old board that are bad are different part numbers. So I need some suggestions and/or help again:

1. Do I find another board for ~$40 that is correct and eat the $13 I spent on this incorrect board?
2. Do I de-solder the good mosfets with different part number and replace the two bad ones on the original board? How likely are they different spec MOSFETS? I tried looking up the data sheet on the new ones and couldn't find them. The original are N-Channel.
a. Speaking of de-soldering the mosfets, any advice here to de-solder them? I have an Ayou Digital Soldering station so it's got good wattage and tips. Do I create a good heat bridge only on the component side of the board and pull or is the large plate that is soldered from underneath accessed via one thru hole?
3. Do I de-solder the right ribbon connector and mount it where it's mounted on the original board? There's a place for it to go there. See attached pic of new board...the spot it should be is where the UPC sticker is located.
4. Same with the left connector, do I de-solder it and move it over 3 pins mounts to the right as it has that available?

Thanks,
Roy

[tw2005]

Re: Is my Panasonic TC-P42X3 PS Bad?

Alright, well I thought I was a detailed oriented person...attention to detail! Well, I'm not in this case. I found this for a great price so ordered it: http://www.ebay.com/itm/TNPA5313-Pan...vip=true&rt=nc

It came in and when I went to bench test the MOSFETS all were good but thought it was odd that it had one extra mosfet (see attached images). Then after I installed the board the two large panel ribbon cables didn't line up to the board connectors. Both boards have TNPA5313 printed on the CKT board but the white bar code sticker on the original says 5313AC and the replacement says 5313.

Also, the mosfets on the new board in the same locations as the ones on the old board that are bad are different part numbers. So I need some suggestions and/or help again:

1. Do I find another board for ~$40 that is correct and eat the $13 I spent on this incorrect board?
2. Do I de-solder the good mosfets with different part number and replace the two bad ones on the original board? How likely are they different spec MOSFETS? I tried looking up the data sheet on the new ones and couldn't find them. The original are N-Channel.
a. Speaking of de-soldering the mosfets, any advice here to de-solder them? I have an Ayou Digital Soldering station so it's got good wattage and tips. Do I create a good heat bridge only on the component side of the board and pull or is the large plate that is soldered from underneath accessed via one thru hole?
3. Do I de-solder the right ribbon connector and mount it where it's mounted on the original board? There's a place for it to go there. See attached pic of new board...the spot it should be is where the UPC sticker is located.
4. Same with the left connector, do I de-solder it and move it over 3 pins mounts to the right as it has that available?

Thanks,
Roy

yeah, revison is important, you've got a 50" board instead of the 42. Moving that connector is not easy, lots of pins. Shopjimmy did have one i though, easier to return it really as it's matched to a 50" panel and why there are some differences. would work and give a picture though.

[niswanger]

Re: Is my Panasonic TC-P42X3 PS Bad?

I just removed the 3 bad MOSFETS from my original SS board. They have Printed on them RJP30H2A. The same MOSFETS on the new board from the same locations (new board does have one extra) are DG301.

Can I remove the DG301s from the new 50" SS board and put them in the place of the RJP30H2As?

Also, it takes a lot of heat on the heat bridge of the back plate to get these MOSFETS to lift. Are they easy to damage with de-soldering and re-soldering? Is this an normal practice to re-use these components?

Thank you,
Roy

[tw2005]

Re: Is my Panasonic TC-P42X3 PS Bad?

more than likely. DG301 is a panasonic IGBT, 330v, 40A, 250A peak

RJP30H2 is a 360V 40A ,

I would say it's fine but if you are repairing yours then replace only what's there but the FET driver IC could be damaged in fact I'd be probing diodes as well unless you just want to take a punt but FET driver IC is advisable.

not familiar with this board so you may have to wait and see if anyone else has done one.