Panasonic TH42PZ80-B Lightning Victim

[davetherave]

Very local lightning strike hit yesterday morning (i.e. simultaneous flash and bang). Since then my Panasonic Plasma hasn't worked. The Sky broadband box is also not working but Sky are sending a new one free of charge.

I've come across this forum trying to see if I can repair the tv myself - I've looked through search and can see similar issues but want to double check the results of my efforts. I'm not particularly experienced but I am confident in following instructions and using multimeter/soldering iron for simple diagnostics/repairs.

I've found the service manual and fairly quickly arrived at a dead end. Here's what I've done (when I say 5V on the following, I'm talking 4.9-5.1V - I assume this is within normal tolerance?):

Plug in, try and switch on, no lights, no clicks.
Check for 240V AC on P board P9 - on and confirmed.
I've checked for continuity across the 5 fuses (F201,301,501,601 and 602) and all ok (well, I tested them on board but as you'll see I get voltage downstream - let me know if I need to take them out to test for this issue).
Check for 5V DC at A7 and confirmed when power button on. 0V when power button off.
Check for voltage on the SS board where the power switch plugs in (SS34) and get 5V there at pin 1. Pin 3 shows 5V and then 0V when I cycle the power button. Pin 2 always 0V.

The service manual is pointing me to the A board but provides no further diagnostics. Is there any further checks I can do and having seen replacement A boards on ebay from supposed write off tvs for £40 is this a road I should be looking at going down…!?

Many thanks in advance,

Cheers, Dave

[davetherave]

Re: Panasonic TH42PZ80-B Lightning Victim

Some pictures to help...

[Caleb]

Re: Panasonic TH42PZ80-B Lightning Victim

Usually lightning kills the A board as it travels down the catv wire, typically the hdmi chip. if you look at the qfp chip just above the vga connector it looks like it might have a pinhole blown in it at the "a" in panasonic. It could just be a dark spot hard to tell without a macro shot of it. Im not terribly familiar with this model but most plasmas have a test jumper on the control board that will light up the tv with test patterns without the mainboard tied in. Hopefully Tom66 or tw2005 will chime in as they are most familiar with the panasonic sets

[davetherave]

Re: Panasonic TH42PZ80-B Lightning Victim

Thanks Caleb. I've attached a macro shot (I'm not at home during the day so I'm afraid the quality of the pics is poor). Was just a dodgy photo - the chip visually looks fine. The power surge took out the tele and the broadband router/modem off the same power socket so I assume the voltage surge/drop entered through the power cable (it wasn't surge protected as I'd swapped the protector out the other week for something else....).

If anyone knows a way of testing as Caleb describes or can confirm that what I've done is sufficient to rule out the P board as being faulty I'd be most grateful. If I'm going to replace the A board then is matching TNPH0740 enough or is the 1 in the circle and A in the square some sort of revision number? There's also a TXN/A1RPTB 1 on a barcode sticker - is this the more specific part number I should be matching?

I've found one here in stock (there's a slight difference in the barcode lettering. If anyone linked to this forum or regularly posts has one they want to sell to me I'd rather give the business to you!!!

Cheers,

Dave

[tw2005]

Re: Panasonic TH42PZ80-B Lightning Victim

https://www.badcaps.net/forum/showth...4&highlight=a5

Pretty sure if you disconnect A5,A6,A7 and turn this on the screen should automatically fire up and be white.

that would confirm everything else is good and bad A-board which is the most likely fault.

this is the revision you'd be looking for and looks like it was fitted to 42,46 & 50" models
TXN/A1RPTB (TNPH0740CB)

There are variations of TNPH0740 so you'll need to match what the numbers above.

[f67bird]

Re: Panasonic TH42PZ80-B Lightning Victim

Don't know if you are up for this kind of soldering... this advice is meant for you and others with the same situation.
If repairing this main board is something you would like to try... The main HDMI ic on this main board is the ADV7495B BSTZ-170 that is directly above the HDMI input connectors in your photo.
If you have chip quik and the flux that comes with it or a good flux, see if you can remove this ic without lifting any of the pads or removing any of the nearby small components. Then remove the remaining chip quik from the pads with desoldering braid.
This ic does not have a solder tab underneath it, so you shouldn't have to use hot air to remove it... although if you do have a hot air gun used at a low setting, it does make it much easier to remove the ic after chip quik is also used.
This will most likely get the tv up and running (without any HDMI or component inputs) if the power supply wasn't hit.
If you want to have an indication that the power supply wasn't hit, you can remove the connectors from the power supply except for the ac input... and check for the standby voltage when you plug it in.

[davetherave]

Re: Panasonic TH42PZ80-B Lightning Victim

Tw2005 - thanks. I didn't come across that post when searching. I disconnected as you suggested and then plugged in and switched on. White screen. Success.

Have removed the A board and will track one down now unless there is a repair service in the uk?

f67bird - thanks for your reply. I confirmed power supply ok and don't have the chip quick as you suggested (I have a simple iron and tube of solder - always on the look out for new tools though so maybe get the wife to get better equipment for my next birthday....

What makes you sure that the hdmi chip is the one that's gone? Is it common that it goes first?

I'll update when the I've got a new A board.

[f67bird]

Re: Panasonic TH42PZ80-B Lightning Victim

I'm not certain that the ic is bad, but it doesn't take long to find out once you get the proper equipment. Hdmi ic's are a weak point when it comes to lightning.
Sometimes you can remove the hdmi ic and have the set come up only to find out that the damage went further than just that ic once you replace it. Many more times the set is fully operational after replacing the hdmi ic.

[davetherave]

Re: Panasonic TH42PZ80-B Lightning Victim

Update. Thanks all, received new A board plugged in and all the working on the tele.

However... the hdmi daughterboard on the onkyo 606 has been fried, and also the freesat box. Freesat box has been replaced under warranty. I don't think the onkyo is recoverable as those HDMI daughter boards are like rocking horse poo. Gives me an excuse to upgrade now.

The surge must have come through the telephone cable blown the adsl router then through the Ethernet cable and into freesat box from there through HDMI to knock out the onkyo and finally tele. Seems as though anything with HDMI boards are fragile - as you had said

Thanks again for giving the tele a longer lease of life.

[davetherave]

Re: Panasonic TH42PZ80-B Lightning Victim

Pic of the daughterboard

[davetherave]

Re: Panasonic TH42PZ80-B Lightning Victim

Otherside

[michael dranfield]

Re: Panasonic TH42PZ80-B Lightning Victim

Its very common for lightning to cause a massive surge on the phone line and damage everything connected to it, in days gone by people use to say unplug your television aerial during a storm , now its you phone line you need to unplug !

[tw2005]

Re: Panasonic TH42PZ80-B Lightning Victim

Yep, HDMI ports seem to be a weak point.

Lost HDMI on my STB and it took out the HDMI port in my Panny but very lucky just the one in use, left me with 3