Panasonic TX-37LX85P blink 3 times

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

Is there an error output on the inverter; are the pins marked at all?

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

should i check voltages on output in the picture?? I think this is high voltage, just to be sure? i see someone replaced the 3 capacitor

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

Don't attempt to measure the high voltage output with meter - over 3000V present on some LCD TVs.

How is the soldering on those caps? Try cleaning up flux.
I see at least one missing - little SMD C6?

I am trying to understand how the inverter is wired up to the main board. Looks like it goes through A13 perhaps?

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

the solder is OK, i now cleaned it. Yes i see that someone is try to "repair" TV.
Yes it is wired with the A board with A13, and with the power board with the P5

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

On A13, there is a pin #4 called "INV_SOS". What does this measure? I think it should be low if OK, high if bad. Also, check INV_ON and INV_VCC; pins 2 and 1 respectively.

Looking at the design of the board, it sends a 5V/12V power rail to the inverter for its logic power, alongside the 24V for the main power supply. I'm working right now on the assumption the power supply failed and sent 17V down the 9V line... this might have damaged the A board (causing your original 3 blinks)... then I think it may have reached the inverter VCC hopefully it's something simple like a blown fuse.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

#4 = 3.27V
#1 goes to 12V but when clicks then 0V, then again 12V -> click -> 0V
#2 = 0V

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

OK, Vcc is OK, but the SOS signal should be a LOW. If you force it low (to pin 6 is fine) using 100~470 ohm resistor, does the TV do a blink code with inverter installed?

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

I used 100oHm resistor, but no change. Still blinking green LED, and clicking sound. I notice that #1 is not used (there is no wire)

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

What does INV_SOS measure on the A board side when you do this?

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

is there difference if i connect resistor on A board or wire or inverter board. I think it is only important to get LOW signal. And what is LOW? is it ok if there is 1V or should be lower?

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

At either end is fine, we are trying to make it less than 0.8V which is the guaranteed low threshold of the 3.3V logic.

[tw2005]

Re: Panasonic TX-37LX85P blink 3 times

Your current LED indication sounds similar to this little LCD I fixed.
https://www.badcaps.net/forum/showthread.php?t=23136

The PSU/inverter was all one unit and it had a shorted P channel H-FET which was situated on my set right before the inverters. On that one disconnecting the backlight allowed the green LED go solid for a moment then SOS1. The TV had already been tuned in so when an antenna was coinnected I did momentarily get sound from a channel.

You mentioned TPC8105 which is a P-channel H-FET. That's what they look like (8pins)

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

i got 0V on #4 pin when i use the 100ohm resistor, should i try with lower resistor?

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

0V is fine, but since you've now disabled the error signal and you still get the blinking green I'd have a look at tw2005's advice.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

i measured the voltages, please have a look at them. I think that something is wrong here.

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

The 3~5V readings do not look good to me, something may be wrong there. With the board powered off, what resistance do you measure between the tab and each of the two pins? It should be >10kohm.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

by the tab you mean the plate? (screw) I measured, on one side is 29kOhm and other is 124kOhm (i measure the regulator pins that is 3.62V on picture)

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

What is the part # on it?
Yes tab = metal fin/plate at top of device.

[rtstorm]

Re: Panasonic TX-37LX85P blink 3 times

1h45sf
fdd
8447l

[tom66]

Re: Panasonic TX-37LX85P blink 3 times

All of them?
https://cdn.badcaps-static.com/pdfs/...5f51094b3a.pdf