Panasonic TX-P42GT20E 3D , does not turn on!

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

Does this mean that the processor is dead? Btw i found a other main board! The one thats in my tv is TNPH0899 but i also found a TNPH0898? Visually it looks the same?

[Neelix]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

3.27V is ok, but with L5481 solderered into the board, we're back to 0V at pin 8. That means that something else besides C5487 is also faulty and pulling the STB3.3V down. The STB3.3V supplies the processor(IC1100) and it's EEPROM(IC1101) with power. Any of of those two ICs or caps on the supply line around IC1100 can pull the STB3.3V down. Only way to find out which IC or cap, is to remove them one and one until the voltage at pin 8 is right again

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

That are a lot of caps! Im looking at the schematic but i don't really see any caps that would stand out for being removed…..

L5481 must be where it is right? any suggestions where to start?

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

C1117 , r1209?

I ordered the main board but I'm willing to fix this main board , i wanna know what the fault is!

[Neelix]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

L5481 is in right place yes. Had a look at the schematic again and if you remove L1100 then IC1100 and all those caps on the supply line is not connectd to the STB3.3V anymore. So remove L1100 and measure the voltage and resistance again at pin 8 of IC5482

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

I don't know which 1 is L1100. Its a conductor and its connected to pin 88 of ic1100 but i don't see it on the print itself. I do see a cap going to pin 88 but i think its a capacitor?

[tw2005]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

I don't know which 1 is L1100. Its a conductor and its connected to pin 88 of ic1100 but i don't see it on the print itself. I do see a cap going to pin 88 but i think its a capacitor?

use the pdf manual and the find function. it's on the opposite side of the board near the Sd slot and in between that and cn8700, c1102 is next to it

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

Huh? I did haha , when i type L1100 i only find the 1 thats near the IC1100? I already thought it was on the opposite side of the board as it goes to the small cap that goes to 2 small "rings"......

Do i use the wrong reader for the manual? I dont get it

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

Ok , searched for it again on a windows machine and now i find the L1100 ..... thx!

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

L5481 is soldered into place , L1100 is removed and mm now measuring 3.27V + 4.7V again! Im now measuring "OL" Ohm again , so there is another short right?

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

But also , I cant just simply remove all components untill the shorts are gone right? They are there for a reason...... ( Got a spare mainboard to replace components ).

[Neelix]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

We're making progress! 3.27V and high resistance is what you must measure at pin 8. With L1100 in the board, you measure 0V and low resistance. By removing L1100 you took IC1100 and all those little caps out of the circuit and now you measure 3.27V and high resistance at pin 8 which is right. That means that IC1100 or the caps is shorted and when in the circuit, is pulling the voltage at pin 8 down to 0V. Next is to find out if it's the IC or the caps that's shorted and which caps. I suggested previously that you remove the caps one by one, but that's going to take too long and the connectors might break from all the unplugging and pluggin in of the board. So I suggest you remove all the caps(C1102, C1103, C1104, C1108, C1109, C1123, C1114, C1112) at the same time, solder L1100 back into the board and measure again the voltage and resistance at pin 8. If you the measure 0V and low resistance, then IC1100 is shorted and must be replaced. If you measure 3.27V and high resistance, then one or more of the caps you removed is shorted and you must measure the resistance of each to find the shorted ones

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

Thx for the big help Neelix , I will just replace IC1100 to see if it will turn on or not. ( Would save me alot of time removing all caps/replacing them. )

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

I replaced IC1100 and still does not turn on. Voltages are the same.
Will remove and replace the other ones.

[Neelix]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

Must be one of the caps then that is pulling the voltage down at pin 8

[Moreno83]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

I gave up , those caps are TO small to change! My solderiron is to big for those caps ....need a thin iron to replace those!
New mainboard is coming this week...will let you know how it works

[CyborPerez]

Re: Panasonic TX-P42GT20E 3D , does not turn on!

hola, un saludo para todos, sucede que tengo esta mainboard TNPH0899 1A, me gustaria saber si alguien aca me puede facilitar el diagrama de esta placa, o saber donde van los voltages de cadda cable que ingresa de la fuente a la placa, donde estaria stb y el power on, porfavor me podrian ayudar? Les agradeceria esa colaboracion. Gracias.