Panasonic TC-P46G25 10 Blink Code After Power On

[krygods]

After power on the standby light blinks 10 times continuously.

My trouble shooting plasma TVs is very limited so I don't know what voltages are supposed to be present etc.

I've taken pics of the boards as the are in the TV and top and bottom of the PSU.

What would be the next step in troubleshooting the problem with this TV?

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

After power on the standby light blinks 10 times continuously.

My trouble shooting plasma TVs is very limited so I don't know what voltages are supposed to be present etc.

I've taken pics of the boards as the are in the TV and top and bottom of the PSU.

What would be the next step in troubleshooting the problem with this TV?

Common failure with these is the Sc board. Can produce a number of blink codes including 10 blink.

I've marked 6 items to disconnect, then power on and see if it turns on with no blinks. SC, SS, P35, 3 white ribbons.

Do it long enough to verify then turn off. Do not reconnect sc, ss and P35 for at least 5mins to let the voltages to drop or else you may damage the board and with P35 a spike there can damage the panel.

If you have a multimeter check resistance at SC2 across the pins, have it set in megohms, could be shorted or find Q661 on the SC and see if that is shorted.

If you still have 10 blink then it's most likely on the A board, if not then P and A boards are ok and I'd check the SC

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Unplugged the six item you marked.

TV power on and off without the 10 blink code.

If the TV is left on long enough it will shut itself off and flash a 4 blink code.

Here is a picture of the resistance reading across the pins at SC2.

Should Q661 be removed for testing or can it be tested in circuit? What am I testing, GATE to SOURCE and GATE to DRAIN?

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

this will help too. if the SC is bad, you must check the sd/su too in case they are also shorted. Usually ok but not always.

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Unplugged the six item you marked.

TV power on and off without the 10 blink code.

If the TV is left on long enough it will shut itself off and flash a 4 blink code.

Here is a picture of the resistance reading across the pins at SC2.

Should Q661 be removed for testing or can it be tested in circuit? What am I testing, GATE to SOURCE and GATE to DRAIN?

yeah, that's why you power up just long enough or less than 30sec, they do that as I found out when I left mine on.

What's the limit of the meter for resistance? 75K is bad. Traditionally sc2 goes short then you'd have 4 blink but when it does not then 10 blink as IC521 also is a fail point and that affects the 15V line.

Won't matter which way you test Q661, do it in cct. If the Sc has died 99.9% assured Q661 will be shorted across all 3 pins

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Range of the meter is Mega Ohm.

You are right about Q661, shorted across all three pins. Resistance reading is 3 Ohm across all three.

So is the SC easily repairable? I see a few SC board available but expensive $175.

Also what must be done to check the sd/su. I'm assuming those are the upper and lower buffer connected to the SC?

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Range of the meter is Mega Ohm.

You are right about Q661, shorted across all three pins. Resistance reading is 3 Ohm across all three.

So is the SC easily repairable? I see a few SC board available but expensive $175.

Also what must be done to check the sd/su. I'm assuming those are the upper and lower buffer connected to the SC?

yes, have you opened that doc I uploaded? It's all in there except component repair. LOL.

I think they're easy if you have good soldering skills. Trick is getting it right first go. There are repair services although regrettably Moduslink who were very good have shut down. Ebay has some, at least one has used some of the info here to work them out.

i do have a very long TNPA5081 thread that will identify parts and what I've done.

Some have simply failed following it but i've done 7 and apart from the first one, most I've got first go.

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

I've glanced at it I'll go ahead and read through it now that I have a general idea of what the problem is.

Soldering is not a problem for me, I spent a few years soldering as a profession so not much trouble for me when it comes to soldering.

Are the components to repair the board readily available?

Can you post a link to the thread you mentioned?

By the way thanks for the help and insight.

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

I've glanced at it I'll go ahead and read through it now that I have a general idea of what the problem is.

Soldering is not a problem for me, I spent a few years soldering as a profession so not much trouble for me when it comes to soldering.

Are the components to repair the board readily available?

Can you post a link to the thread you mentioned?

By the way thanks for the help and insight.

Sure, no worries. I spent literally months trying to decipher all the parts and surface stuff then found UTSOURCE in china and that solved the parts problem although I'm not sure how genuine some parts are but whatever they've supplied has worked.

https://www.badcaps.net/forum/showthread.php?t=26322

starts off as you'd expect, me not knowing much but it should get you there in the end.

There are kits but there are some items i would strongly suggest to replace regardless of whether you think they are bad or not unless you can be 100% sure.

watch out for the 30f125 IGBTs. They can be missed as often 1 of these will fail but not fully shorted, maybe 250-300ohms so doing a simple short check people have missed these which means the board just blows again

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

I'm trying to find where in the trouble shooting it explains how to test the sd/su.

All I see is how to isolate them to determine if one or the other is bad, but am I wrong in assuming that the SC must be functional in order to isolate the sd/su to determine if one is bad?

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Marked from memory, keep an eye out for burn or failed gate resistors, best measured but over all I think I've had 1 bad resistor. If you download a service manual and check the schematics of the parts I've labelled you'll see how they relate, particular Q661 and that inverter cct which has to be 100% or pop.

I've used a 50" board since it's a clear image but they all fail the same.

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

I'm trying to find where in the trouble shooting it explains how to test the sd/su.

All I see is how to isolate them to determine if one or the other is bad, but am I wrong in assuming that the SC must be functional in order to isolate the sd/su to determine if one is bad?

well you're very close, try slide 42 on. just resistance check it as per the guide

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Here's what I've found with the buffers

TPSU15 - 5.41M OHM
TPSU16 - 218.3K OHM
TPSU17 - OPEN
TPSU18 - OPEN

TPSD26 - OPEN
TPSD28 - 218K OHM
TPSD29 - 5.04M OHM

TPSU18 is supposed to be reference to GND? I don't understand why I don't get a resistance reading when I test TPSU18.

Troubleshooting guide also says the TPSU17 is supposed to measure around 5.7M OHM but I see nothing there either.

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Here's what I've found with the buffers

TPSU15 - 5.41M OHM
TPSU16 - 218.3K OHM
TPSU17 - OPEN
TPSU18 - OPEN

TPSD26 - OPEN
TPSD28 - 218K OHM
TPSD29 - 5.04M OHM

TPSU18 is supposed to be reference to GND? I don't understand why I don't get a resistance reading when I test TPSU18.

Troubleshooting guide also says the TPSU17 is supposed to measure around 5.7M OHM but I see nothing there either.

all those fancy ref points confuse me but to simplify this.

Vfg is thos metal bolt hole tabs, it's floating gnd so just measure from that to each of Vfo, vscn-f and 5V-f. could try reverse polarity of the probes but 218K is looking good, vfo mostly goes short if bad so assuming you're doing this right then so long as the resistance of the other 2 is equal to or higher and not shorted I will say they're ok.

not the first time someone has come back with open or high resistance, could simply be the type of meter, don't know why. My old fluke 75 gets pretty close to what they state.

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

So all the parts that you marked in the picture, is this all of the components that you recommend replacing or are there others? I'd much rather just buy all the components that you've had to replace in the past and replace them all regardless if they test good or bad.

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

So all the parts that you marked in the picture, is this all of the components that you recommend replacing or are there others? I'd much rather just buy all the components that you've had to replace in the past and just replace them all regardless if they test good or bad.

There could be some others but only my first board which as a result of a about 5 failed attempts i ended up with over 30 bit. to get it going.

So on that marked image, it'll take a lot of effort quoting the locators, do my best.

The larger 78M05 reg, i will say is ok to leave but they give a resistance to check in that guide. Only on a TV with bad buffers and the 5V rails on the Sd/su were shorted did i need to replace this.(first board)

Q661 you know is bad, Q660 jsut check in case but expect good.
These i would replace as part of Q661
Q701,Q702, Q818, IC773, IC771.

PC461 opto i forget how i checked but I think across the Vcc/gnd would be a good start . I think the same 5v line that feeds that small schmitt inverter Ic feeds this and I've given some resistance on a good board in the thread.

I've replaced 1, again my first board only.

Currently i'd expect the 5v out of that 78L05 to be shorted.

The DG402 expect both shorted, same DG502 both dead, 30f125 expect 1 bad but i have replaced just one and both with success, safe option would be do both.

45G128 and the TO220 diode next i expect shorted

IC521 often bad bad but I always replace this.

That surface diode next to this often shorted, replace. then either check those pnp/npn sanyos or replace. usually ok maybe one of these once or twice I forget.

i have put all of my board histories if you take time to read. not sure if all the ones I've done but enough of get an idea.

check those 100 ohm resistors , usually ok but if bad there's a chance the small octal buffers or inverter ICs have taken a hit right where SC20 connector is, again only on my first board.

check gate resistors and i always bell out all of those large items on heatsinks but only after you remove the obvious stuff I mention as a shorted IGBT will also show short on the diodes.

hope I have not missed anything. I think 7 parts has been my best effort but usually what I've mentioned above.

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

Thanks for the run down, I'm about three or four pages into the 15 page thread so I'll get through it in my free time and of course go over it a few more times before I attempt the first repair.

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

So far I have found these that are all S/C both directions.

D451
D673
D674



These are also both S/C

Q452
D482



These transistors the collector and emitter are S/C

Q402
Q403



IC773, Schmitt inverter(HA) - How is this tested? Can't find datasheet.

[krygods]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

I tested the buffers this time without using an alligator clip extension for the GND I get a reading now except for the VF-GND (PIN 9) I still can't get a reading just shows open no matter the polarity of the probes.

SC Board
5V_F 5.3M OHM
VSCN-F 218.3K OHM
Vfo 5.41M OHM
VF-GND I still can't get a reading with the probes in either direction

SD Board
5V_F 5.4M OHM
VSCN-F 218.4K OHM
Vfo 4.96M OHM

[tw2005]

Re: Panasonic TC-P46G25 10 Blink Code After Power On

To be honest I would just remove IC773, it will be shorted but since you ask simply measure resistance across Vcc - gnd pins 5 & 3. You wil also find the same resistance across gnd and O/P on Ic771 and often once IC773 is removed that will be ok but I'd replace that small reg too. pay close attention to the correct part number as the suffix determines the size but I have listed a TI direct replacement number too in that thread(SN74AHC1G04DBV)

D673,674 will be because q661 is, you need to remove the failed IGBTs first , then recheck the diodes.