samsung ln46a540p2fxza red light blinking

[cjrolke]

Hello

I have a samsung ln46a540p2fxza and the red power light is blinking, every once in a while I hear the relay on the power supply click. the screen never lights up and I can not get to a menu on the screen. I have pulled the board and looked over the capacitors, none were bulging I still went ahead and replaced some of the normal ones that go bad (the 10v rated ones)

put everything back together and I am still having the same problem. what else can I do to troubleshoot this unit?

I have seen a post on the internet about a bad chip would this help?

is there any locations for a testing point to determine the issue?

thanks

[budm]

Re: samsung ln46a540p2fxza red light blinking

Please up load good clear pictures of the whole back side of the TV so we can see how all the boards are connected together, then the pictures of the power supply board. BN44-??????

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

here are picture of inside the TV let me know if you need more

[budm]

Re: samsung ln46a540p2fxza red light blinking

So the power supply-Inverter board combo is P/N BN44-00202A.
Here is the diagram.
Pictures provided by SHOPJIMMY.
http://www.shopjimmy.com/samsung-bn4...er-supply.htm#

The relay coil is running of the 5.1V STANDBY POWER SUPPLY.
The black connectors on the power supply board have the labels to tell you what each pins are, you need to report the DCV reading of each pin, MAKE SURE to put the PIN NAME for each pin so we can see what are missing.

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

ok
cn 1805
1 .05
2 2.36
3 4.64
4 2.37
5 .03

cn1806
1 11.92
2 0
3 0
4 0
5 0
6 10.50
7 10.54

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

J 890 (big connector)

1 4.10
2 2.26
3 5.16
4 0
5 0
6 0
7 13.94
8 13.95
9 0
10 0
11 0
12 0
13 5.15
14 5.15
15 5.15
16 5.15
17 0
18 0
19 13.56
20 0
21 13.56
22 13.56
23 0
24 0


thanks

[budm]

Re: samsung ln46a540p2fxza red light blinking

Please put the name of the pin after each readings.
'The black connectors on the power supply board have the labels to tell you what each pins are, you need to report the DCV reading of each pin, MAKE SURE to put the PIN NAME for each pin so we can see what are missing.'

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

cn 1805
1 .05 inverter o/off
2 2.36 nc
3 4.64 pwm dim
4 2.37 gnd
5 .03 det_5v

cn1806
1 11.92 12v_cold
2 0 fb
3 0 fb
4 0 gnd
5 0 gnd
6 10.50 ld
7 10.54 ld

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

J 890 (big connector)

1 4.10 ps-on
2 2.26 sync
3 5.16 stbs 1v
4 0 gnd
5 0 gnd
6 0 gnd
7 13.94 13.0vs
8 13.95 13.0vs
9 0 gnd
10 0 gnd
11 0 gnd
12 0 gnd
13 5.15 5.1v
14 5.15 5.1v
15 5.15 5.1v
16 5.15 5.1v
17 0 gnd
18 0 gnd
19 13.56 13.0vm
20 0 gnd
21 13.56 13.0vm
22 13.56 13.0vm
23 0 nc
24 0 nc

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

here are close up shorts of both boards

thanks

[budm]

Re: samsung ln46a540p2fxza red light blinking

cn 1805
1 .05 inverter o/off
2 2.36 nc
3 4.64 pwm dim
4 2.37 gnd
5 .03 det_5v

cn1806
1 11.92 12v_cold
2 0 fb
3 0 fb
4 0 gnd
5 0 gnd
6 10.50 ld
7 10.54 ld

OK, the main board is not sending the Backlights ON (>2VDC = ON, <1VDC = OFF) signal to turn on the backlights inverter circuit, but you need to verify the reading on pin which is GND pin, you show the reading of 2.37V, it should be 0V.

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

I will verify when I get home

thanks

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

I just reset ed the cables and tested

1. 0.03. Inverter
2. 2.38. NC
3 4.63. Pwr dim
4. 0 gnd
5 5.15. Det_5v

[budm]

Re: samsung ln46a540p2fxza red light blinking

I just reset ed the cables and tested

1. 0.03. Inverter
2. 2.38. NC
3 4.63. Pwr dim
4. 0 gnd
5 5.15. Det_5v

That one is still bad.

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

So what is my next step?

[budm]

Re: samsung ln46a540p2fxza red light blinking

http://www.shopjimmy.com/catalogsear...sung+ln46a540p

Which one of these is your main board? You may have the bad C102 SMD cap bad on the main board.

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

One thing that is bizarre is I am getting an A/C voltage rating on the outside of 2 capacitors. Numbers cm808 and cm 807. They are reading an A/C voltage of 60 volts to the to of the capacitor

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

For the main board I see a part number of bn94-02077d

[budm]

Re: samsung ln46a540p2fxza red light blinking

One thing that is bizarre is I am getting an A/C voltage rating on the outside of 2 capacitors. Numbers cm808 and cm 807. They are reading an A/C voltage of 60 volts to the to of the capacitor

You were using the chassis for your Black meter probe, right? Those caps are in the DC primary side so you cannot use chassis GND as the meter GND ref, you have to use the negative leg of the main filter cap as the GND REF for making any DCV reading in the primary side of the circuit. No need to worry about the primary at this point.

[cjrolke]

Re: samsung ln46a540p2fxza red light blinking

I see another part number. Bn41-00975b (2008.01.10)