Panasonic Plasma TC-P42U1 my first plasma

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

i managed to trace voltage to D501 the pic shows voltage readings. i also measured 120v at jg1 and 1v at c604

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

Sorry, didn't see them.

Across TP8/P2 you see pulsing 24V, do you see the same with SS disconnected and SC connected?

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

i dont know why i got 24v before but i get nothing to sc or ss boards from those con. that i can tell.

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

How were you testing it when you had 24V?

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

i get 40v on hot side neer i think there transformers (see pic)
i just had sc con disconnected and turned on power. dvm with grd to frame, it was pusing the 24vac in sequence with front led blink but it doesnt seem to be doing that now. at first i think it shutdown after 7 blinks but now it keeps blinking the code. im not sure.

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

You need to measure DC, not AC. You don't need to measure the AC on the primary for now.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

when i turn it on with both sc and ss plugged in i get about 3v(i thought i saw a surge of 120vdc right away when meter lead touched after power on but it dropped to7v and went down)
sc disconnected 1.5
ss disconnected 2v
i noticed if i hold meter leads to grd and either white wire there seems to be a steady voltage drop so readings might not be acurate.
i think its reading the same voltage drop if the sc or ss are connected or not.
by primary, do you mean hot side?
hope this makes sence.

i may start looking for pb if you think thats where the problem is. i dont want to wast to much of your time.

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

Primary = hot side yes.

I think there might be a problem with your main board (A board) or power supply not turning the TV on properly. You should see a good Vsus around 200V for the rest of the TV to work. Do you have the service manual for this set?

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

yes i have service manual. ill start looking at a board.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

i tried to check voltages on pb at connectors coming from a board.
i got nothing but a few milivolts on a few.

this is what manual says it should be
p6
1, 2, 3 - 15v
4, 5, 6 - g
7, 8, 9 - f_stby
10, 11, 12 - g

p7
1, 2 - 15v
3, 4 - g
5 - stby5v
6 - f_stbyon
7 -
8 - all off
9 - stby_sw
10 - 5vc
11 - ac_low

p34/35(diag shows p34, board shows p35 if i saw it right)
1 - mainsw_1
2 -
3 - mainsw_2

p25
1, 2 - 15v
3, 4 - g
5, 6 - 5vc
7, 8 - g
9 - stby5v
10 - g
11 - panel main on
12 - ps_sos
13 - (nc)
only a few mv registered on any of these

i let it sit plugged in a while and the connectors to sc and ss board read .28mv now

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

I'd look at A board then, it's not turning PSU on. Are all connectors except SC/SS power installed properly?

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

i thought i would mention the relay that you hear click when u power on is there then the 7 blink code
i have everything connected now. as far as i can tell all connections are good. a board is to advanced for me im sure. i dont really unerstand the block diagrams and such.

i dont suppose theres any quik test for the A board. i dont want to take much more of your time on this. if you recommend trying a new A board i will. i just hate wasting $50-100 if thats not the prob.

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

Troubleshooting manual for 12th gen:


Follow the steps for 7 blink code. (It's not the exact same TV, but troubleshooting will be similar.)

BTW, the board I have been referring to as the A board, is the DA board on newer models -- function of D and A board combined into one board.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

the drive circuit leds on sc, ss and the optical connection on A board light up on power up but then fade to nothing.
i disconnected the 3 ribbon cables that go to sc, c1, and c2 on the A board and the drive circuit leds stay on and there was no 7 bink code. it stays solid red. had correct voltage at vsus.
connected just sc and had 7 blink
connected just c1 and c2 and got 6 blink code
while i had all the ribbons removed, and driver circuit led on, i retested conections on pb to the A board.
con 12
15v - good
15v - good
15v - good
g
g
g
15v - good
15v - good
15v - good
g
g
g

con11
5 - 5v - mainsw_1
6 - 3.2
7 -0 - mainsw_2

con13
15v - good
15v - good
g
g
0v - should be 5vc?(i dont know what vc, vf means)
0v - should be 5vc?
g
g
5v - stby5v
g
0v - panel main_on
0v - ps_sos
0v - (nc)

i question voltage on con 11 and 5v seems missing from con 13

you said to follow steps here for 7 blink code (slide#71)

im looking at sos detect section now

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

found this video and did exactly as he said and had same results. his model is different but very similar. he had 3 connectors going to sc board and i have 2

im guessing its the sc board. what do you think?
http://www.youtube.com/watch?v=ZS5vH2Q7RVY

then i found this video and did his test and got the same 8 blink code
http://www.youtube.com/watch?v=yeGEH...eature=related

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

I am way out of my depth here, that looks like one way to fix it but I cannot be 100% because you do not have Vs. I have only successfully fixed one Panasonic plasma and it was old tech.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

i found a sc board on ebay for $60 free shipping, so i grabbed it. everyone else that still had it in stock wanted $100 except 1 other place i found it for $75.
i will update this when i get part and put it in.
service manual says i have to make adjustments to board immediatly after install. is this just for a new replacement? theres a 'quik adjustment after pcb exchange' section

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

Usually you could get some picture noise if it's not adjusted properly, but you'll still get a picture.

[ryan74]

Re: Panasonic Plasma TC-P42U1 my first plasma

i ordered from ebay and the guy listed the part as tnpa-4829 so i emailed him to verify it was a tnpa-4829AD. he replied that part number matched.
i got the sc board today and it is a tnpa-4829AB
there are noticable differences between the two boards.
connection to sd/su boards are slightly different.
i marked a few that i noticed right away in pic below.
can i use this board??
or should i ship it back?
7 day return policy so i have to hurry.

pic 178 is old board

[tom66]

Re: Panasonic Plasma TC-P42U1 my first plasma

You have the 46" version it should still work, but you could not use that on the 50" for example.