Panasonic TC-L47E5 won't turn on [3 red blink code]

[dskall]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

According to service manual 16v and 24v are switched on by input from pin 7. You only seem to have about half the voltage you should at 7.5v and 11.5v
I don't know how pfc works by boosting voltage either.

[dick_barton]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

I'm reading 11.5v between TP7414 and chassis/ground.

Also reading 11.5v between TP7415 and chassis/ground.

I'm reading 7.5v between TP7430 and chassis/ground.

Also reading 7.5v between TP7431 and chassis/ground.

Here's a picture of my test... Red probe goes to test point on p-board, black is to chassis. I have aligator clips [presumably] grounding the p-board to the chassis so it "thinks" that it's all assembled correctly. There's no way to reach the test points with the board bolted to the chassis. The book under the p-board is insulating anything from the component side from shorting to the chassis as well as propping the board up at an angle. Pretty sure I'm doing this right.

Did you have Pin 7 shorted to 5.3V when you tested the voltages above? What voltage do you have across the two legs of the 68uF 450V capacitor C7213. Mainboard disconnected from power supply.

[corksil]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

Did you have Pin 7 shorted to 5.3V when you tested the voltages above? What voltage do you have across the two legs of the 68uF 450V capacitor C7213. Mainboard disconnected from power supply.

I just shorted pin 7 in the p2 connector to TP7412 (5.3v) and tested the four points again. Now I'm getting a healthy 16v and 12v reading.

16.1v between TP7414 and chassis/ground.

16.1v between TP7415 and chassis/ground.

12.0v between TP7430 and chassis/ground.

12.0v between TP7431 and chassis/ground.

By 'main board' I'm assuming you mean "a-board" which is the one with all the usb/hdmi connectors etc. I disconnected plug P2 from the p-board and the voltage at capacitor C7213 is still 166V.

With pin 7 on the P2 connector (plugged back in) shorted to TP7412 (5.3V) I re-tested the following from earlier and this is what changed.

Before shorting pin 7 to TP7412 (5.3V), I had nothing on TP7508 or TP7514. With pin 7 shorted, I now have 16.1v on both TP7508 and TP7514.

Before shorting pin 7 to TP7412 (5.3V), I had nothing on TP7512 or TP7513. With pin 7 shorted, I now have 24.2v on both TP7512 and TP7513.

[Repeating earlier tests]

With pin 7 on the p2 connector shorted to TP7412 (5.3v), I have 150v at TP7201.

Without pin 7 shorted, I read 66v between TP7201 and chassis/ground.

[Repeating earlier tests]

With pin 7 on the p2 connector shorted to TP7412 (5.3v), I have 387v between TP7203 and TP7201 [which is the ground side of the biggest main capacitor on the hot side of the board/main filter capacitor.]

Without pin 7 shorted, I read 168v between TP7203 and TP7201 [which is the ground side of the biggest main capacitor on the hot side of the board/main filter capacitor.]

[Repeating earlier tests]

With pin 7 on the p2 connector shorted to TP7412 (5.3v), I have 387v at the CT215 terminals.

Without pin 7 shorted, I read 166v at the CT215 capacitor terminals.

For clarification on power board you have a side marked hot and a side marked cold with lines around each. Okay, I see that now.All measurements on hot side. The ground reference point will be neg. of your main filter cap. I have no continuity to ground on the negative terminal of that biggest capacitor on the hot side. Don't know if that's normal or not.For cold and all others the ground will be chassis.

[corksil]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

Alright, I think I was testing some of this incorrectly. The above post should be clear in describing exactly what the current situation is. I literally re-tested and double-checked all of it 3 or 4 times before posting it. Thanks for the help, I wouldn't have any idea what I was doing if it were for you guys!

[corksil]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

Helloooooo?

[dick_barton]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

Politely put I hope, but please remember that this is a help page with people offering their own time and experiences. They do have families, work and a life to get on with.

If you now have the 16V, 24V and Standby voltages at the output connector as well as your PFC voltage of 387V across the main capacitor then it looks as though your power supply is working OK and the fault must be that the mainboard is not sending the signal to Pin7 of the connector.

Connect another 1K resistor from Pin7 to BL_ON (Pin 11) and check if your backlights now come on.

[corksil]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

No disrespect intended. Honestly, I'm just appreciative for the help.

Alright this is getting complicated. With Pin 7 on the p2 connector on the p-board shorted to TP7412 (5.3V) -- this gives me 387V at the main capacitor. Then I connected a 1k ohm resistor between pin 7 and pin 11, and it did not appear that anything happened.

I checked a lot of test points on the p-board after doing this and most had either 12/16/24v.

Nothing appears to have happened. I don't believe the backlight came on although I'm not exactly in a dark room and it was hard to tell. I did not hear any clicks or noise or anything and my face was 4 inches from the backside of the TV with the rear cover removed and all of the circuit boards exposed.

The only result from this is that the red power light on the front of the TV is no longer "blink blink blink, repeat..." and giving a 3 blink code. At no point in any of this testing would the TV power on via the power button or the remote.

Now I plug it in and it's not even giving the 3 blink code. Seems completely un-responsive.

Any help is appreciated.

[corksil]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

Not sure if it means anything but I used to test 5.3V from TP7412 to chassis/ground. Now I repeat the same test and am seeing 7-7.5V fluctuating between TP7412 and chassis/ground. Hopefully I didn't screw anything up.

[dick_barton]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

The test is done with the main board still disconnected. With Pin7 connected to standby earlier you said you had the supply voltages 16V and 24V as well as the 387V PFC voltage so at that point I would say your power supply is working.
The last test was to add another 1K resistor from standby to BL_ON to test the backlights and hopefully see them come on which you normally see through holes in the rear panel.

Can you confirm that you still have the 16V and 24V at the output connector when Pin7 is connected to Standby?

[corksil]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

Is "standby" the 5.3V that I had on TP7412? I'd like to make sure that I understand you.

Thank you for your help. The world needs more people like you who know how to repair things instead of simply throwing them in the trash and buying new.

[corksil]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

16V on pins 1, 2, and 3 of the P2 connector.

Pin 4 is 0V
pin 5 is 11.8,
pin 6 is 0V,
pin 7 is 11.8 (which is also connected to TP7412),
pin 8 is 100mV and drops gradually,
pin 9 is 100mV and drops gradually,
pin 10 through 14 are all 100mV and dropping gradually
pin 15 is 0V

The main capacitor is still 387V

I don't have 24v anywhere on the output connector.

24.0v on both TP7512 and TP7513

16.0v on both TP7508 and TP7514

Now I'm going to try adding the resistor again and seeing if I can detect any activity from the backlight.

[dick_barton]

Re: Panasonic TC-L47E5 won't turn on [3 red blink code]

The voltages you have given match the service manual.

I would now concentrate on the backlights to see if they are working.

So again with the mainboard disconnected bring up those voltages again as you did above but also add a 1K resistor from Standby Pin 5 of connector P2 to BL_ON Pin 2 of connector P4