Panasonic TC-P46C2 -- Completely Dead

[aaronwt6]

Well, after all the learning I've done here I rarely get stumped on troubleshooting any more but this one has me guessing. Picked up the TV for $10 a couple days ago with problem unknown. Was told it wouldn't turn on. I got it up on the bench last night and plugged it in to check it out.

When the power is connected, there are no clicks or noise whatsoever. I'm not sure if the P board in this model is supposed to engage or not upon connection but most Panasonic sets I've dealt with do so I'm suspicious of the supply. However, it does have 5V present on the standby pin so I'm not real sure. Pressing the power button has no effect on it at all so that makes me wonder about the A board.

Other things to note. Per the attached picture, the pins labeled Main-SW1 and Main-SW2 have 5V on them even when disconnected from the A board. And STBY5V-ON never goes high, nor do the relays engage when I force that pin high.

My question is, am I going about forcing the P board on the right way or am I missing something? The P board is only around $40-$50 but I don't want to throw boards at this thing for no reason.

Thanks in advance for any assistance!

Aaron

[ReeceyBurger123]

Re: Panasonic TC-P46C2 -- Completely Dead

Have you tried unplugging the sustain boards and seeing if the tv turns on, if not I would say A board at fault unfortunatly they are quite hard to find.

[tw2005]

Re: Panasonic TC-P46C2 -- Completely Dead

well i've never forced a panasonic P-board but general rule is if 5v stdby is there but no relay clicks, no stdby led it's A board but I'd be having a good look at the SN and SS for shorts too before you open the purse. TNPA5072 shorted at SS11 is pretty common of this gen , I think 4 x RJP30E4 IGBTs go short.

have you tried disconnecting the SS & SN at the same time and tirning it on? probably be same result might be worth a shot, and I think the A boards for these are nearly extinct or very pricey,

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

I've confirmed that the sustain boards are not shorted. Like I said, I just thought it was strange that there were no clicks from the relays when the power is connected, but the A board was pretty much where I was at on it. I did check and verify that I have 5V going to the power button and remote sensor and that gets pulled low when the power button is pressed.

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

Considering sending the A board to Moduslink PTS for repair. I've sent 2 other Panasonic A boards to them with good results.

The reason I was asking about the supply was I'm used to older Samsungs and LGs that can be forced on with no main board. It's nice to see everything working before dumping money in to something.

[tw2005]

Re: Panasonic TC-P46C2 -- Completely Dead

probably the only option unless you know someone with a 42,or 50c2 for a quick a-board swap to confirm

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

Ok. I'm going to proceed with that for now. If anyone knows how to engage the relays on that supply though to check voltages on the bench I'm all ears. I'm usually pretty good at figuring them out but this one really has me puzzled.

[ammarben]

Re: Panasonic TC-P46C2 -- Completely Dead

perhaps panel main on with 5vstb

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

Tried that too. I cannot get the relays to click on with any combination. I'm not sue if I need multiple things engaged or what. I find it strange that the SW1 and SW2 pins have 5V on them with nothing attached. Makes me think that those may need to be pulled low but I don't want to try it without verification.

[tom66]

Re: Panasonic TC-P46C2 -- Completely Dead

SW1,SW2 are for AC power switch. One is source, the other is sink. If you press the toggle power button on the side of the set the voltages should change.

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

I'll look at it again when I get home from work Tom. The power button is on the front of this model and doesn't seem to have any effect on the state of it. There is 5V going to the button as I've already verified. And it goes to 0V while the button is pressed so that parts seems to be ok. However, none of that affects the voltages on the supply at all.

Any idea if this supply should have any active relays when it's plugged in? I know my 55ST30 and a few other models I've worked on from this era do.

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

Per this thread which I somehow missed before opening my own, I'm even more confident on the A board. Sounds exactly like what mine is doing.

https://www.badcaps.net/forum/showth...light=TC-P46C2

I'm going to give it a shot at Moduslink PTS and see how it goes. I've only got $10 in to the TV right now so even if I end up at $100 or a bit more that's not too bad for a 46" set.

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

perhaps panel main on with 5vstb

Thanks for the suggestion on this. That did the trick. Voltages are all present and stable so the A board is off to Moduslink PTS today for repair. I'll give an update once I have it back but I am certainly expecting the TV to power right up at that point.

[Andrew F. Ali]

Re: Panasonic TC-P46C2 -- Completely Dead

Step 1: Disconnect all the connectors on the PSU Board, except AC input connector.
Step 2: On the PSU Board P7 connector, connect a 1K resistor across Pin 1 (STBY 5V) and Pin 5 (F-STBY-ON). Then using another 1K resistor connect across Pin 1 (STBY 5V) and Pin 7 (PANEL-MAIN-ON), on the PSU Board P7 connector.
Step 3: Connect two (2) 120Vac 60W light bulbs in series. Then connect the resulting two (2) wire ends across the P2 (V-SUS Output and GND) connector.
Step 4a: Measure the DC Resistance across P34 (There is no connector). If it reads 0 ohms. Plug in the 120vAC to the PSU Board.
Step 4b: Measure the DC Resistance across P34 (There is no connector). If it reads 'open' solder a wire across the point where Pin 1 and 3 would be. Plug in the 120vAC to the PSU Board.
If the PSU Board is working the Two (2) light bulbs should glow bright. Vdc measurement across P2 will be approx. 190Vdc.

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

Step 1: Disconnect all the connectors on the PSU Board, except AC input connector.
Step 2: On the PSU Board P7 connector, connect a 1K resistor across Pin 1 (STBY 5V) and Pin 5 (F-STBY-ON). Then using another 1K resistor connect across Pin 1 (STBY 5V) and Pin 7 (PANEL-MAIN-ON), on the PSU Board P7 connector.
Step 3: Connect two (2) 120Vac 60W light bulbs in series. Then connect the resulting two (2) wire ends across the P2 (V-SUS Output and GND) connector.
Step 4a: Measure the DC Resistance across P34 (There is no connector). If it reads 0 ohms. Plug in the 120vAC to the PSU Board.
Step 4b: Measure the DC Resistance across P34 (There is no connector). If it reads 'open' solder a wire across the point where Pin 1 and 3 would be. Plug in the 120vAC to the PSU Board.
If the PSU Board is working the Two (2) light bulbs should glow bright. Vdc measurement across P2 will be approx. 190Vdc.

Thanks. I basically just powered it up in the TV like you're describing. I got a brief screen glow and unplugged. The A board was not responding to the power button or the remote, nor was it sending voltage to the PNL-MAIN-ON pin so it's off for repair.

[Andrew F. Ali]

Re: Panasonic TC-P46C2 -- Completely Dead

Thanks. I'm glad I could've been some help. When you get the A-Board repaired and re-installed please remember to give us some feedback.

[aaronwt6]

Re: Panasonic TC-P46C2 -- Completely Dead

Just a follow up on this. Received the repaired board back from Moduslink PTS and the TV is now up and running. Looks like they either replaced or reseated the main processor chip on the board. Not sure if there was anything else but that's the only thing that I noticed.

Thanks to everyone for the tips and advice.

[galo2k]

Re: Panasonic TC-P46C2 -- Completely Dead

hello I have a TC - P46C2 , panasonic 46 inch tv, i purchased the power board and the Y-asus board, I still have the 10 blinking lights, now theyre telling me that I need the main board, how can i test to see if the main board is the problem?

[tw2005]

Re: Panasonic TC-P46C2 -- Completely Dead

hello I have a TC - P46C2 , panasonic 46 inch tv, i purchased the power board and the Y-asus board, I still have the 10 blinking lights, now theyre telling me that I need the main board, how can i test to see if the main board is the problem?

Who's they?

Could be main, or a number of things. Since you've done the SN and P boards, could be main or even the SS board which in this series tends to short.

Try this.

Disconnect SN2, SS11, P35, the 3 white ribbons at the A board. Turn the TV on. If it powers up with no error blink then the A board should be fine.

if it still 10 blinks I'd go A board.

If not I would then look at the SS board for dead short on the Vsus or the RJP30E2 (x4) transistors could be shorted.

Be careful with these as the SS is connected to the SN board and you can blow up the SN with a bad SS.