Panasonic TX-37LX85P blink 3 times

[rtstorm]

Hi, i have problem with Panasonic LCD TV, when pluged in there is no picture just red LED blink 3 times. I think it's a faulty PSU.

I upload the picture of power suply board, on output i got 5V and 1.1V, all other pin are 0.

PSU model is: TNP8EPL90

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

Here is SM:
http://www.tgohome.com/ServiceManual...&Search=Submit

3 blinks - A Board SOS.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

oh thank you, i take it and have a look, and i see some burned SMD resistor. but don't know whats wrong.

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

The A Board 3 blinks SOS is built around a circuit shown on page 49, see AG_SOS. If one of the resistors in that area is burnt out the A Board may mis-detect a fault and do the 3 blinks.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

I remove the burned resistor, and mark it on picture. How can i find it on TV manual scheme. There is no designation on resistor. I look under page 49, but can't understand the markings.

[selldoor]

Re: Panasonic TX-37LX85P blink 3 times

Which board are you on?

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

I am on A-board (TNP8EAL90), back side.

[selldoor]

Re: Panasonic TX-37LX85P blink 3 times

can you read the part numbers on the two 8 legged devices?

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

1st part
tpc8105
h 7:43

2nd part
3544
8g77

[selldoor]

Re: Panasonic TX-37LX85P blink 3 times

Clutching at straws here but you can see TP1028 in your pic. If you open the manual pdf and search for TP1028
it comes to page 50 of 70 If you pan to the right past c1020 16v 0.1 - check if that is the value of the round blob on your picture? (Clearer pics required) then it says
L1029 ( That is an inductor probably black surface mount) then it says TV-SUB-ON. Well just below that is a resistor R1007 47 It is the only Resistor showing in that area. So that is my guess, but its only a guess.

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

How sure were you of it being a resistor?
Could have been a ferrite bead.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

i am not sure, i think it's a resistor. It was black with no marks

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

That is a ferrite bead.
Value is not critical.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

so i can use similar? and then test it?

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

Yes, you can use basically any ferrite bead as a replacement. As long as it is the correct size.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

i replace it, but no change, still 3 red blink

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

OK, please locate test point TP7022 and check the voltage there.

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

Oh, I just realised TP7022 isn't visible, but you can test the pins of Q5615, which is in section D4 (near IC5600)

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

all 3 pins are 0V

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

OK, there should be a capacitor marked 100 (metal can) nearby. Can you check the voltage across it? Can you post a picture of the area around that transistor?