Sony KDL-46EX400 2 blink error code

[tibimakai]

I ha picked up another one of these. Last time it was keep clicking and it would not turn on.
By replacing the main board, it fixed the TV.
Now it's a bit different issue. When I plug it in, it would turn on(click only) and then off and would set a two blinking error code, which is the power supply board error.
There is no backlight turning on.
It seems that It has a BL_Error code, constant 3.3V while it is plugged in.
It doesn't have any voltage at T_con on or T_con 12V.
Here are the voltages that I'm getting:
T_Con_on= 0V
T_Con_Vcc12V= 0V
Dimmer= 0.02V off and 2.95V on
BL_On= 0.01V off and jumps to 0.43V then goes to 0V when on
BL_Error= 3.333V on and off
Reg 12V= 0 off and 12.72V on
Audio 12V= 0V off and 12.73V on
Pwr On= 0V off and 3.3V on
AC_Off_Det= 2.78V off and 2.78V on
STBY 3.3V= 3.3V both ways

Inverter connector
Vcc_12V= 12.67 on and 0V off
FB= 0V on and off
LO= 12.03V on and 0V off

What is interesting, is that I have replaced the main board with the other TV's bad board and it has the same symptom, 2 blink error code. Now I'm thinking, that main board is not bad after all? Why it was constantly clicking and now with this TV doesn't do that?
I have made some pictures with my phone, just to start this thread.
I will make some proper ones tomorrow.
Any help would be appreciated.

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

I would like to test the inverter board's test points as in the Youtube video, but it seems like I'm not getting that 0.2V AC as him. Not getting almost anything.

[kevinm34232]

Re: Sony KDL-46EX400 2 blink error code

That trick didn't really work for me either trying to isolate the bulb. Check the single leg of the 3 leg diode to the right of the transformer, Im not positive, but I think if you get the 12V there that is indicating backlight problem. In my case I got backlight for a the 2 seconds.

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

I have a feeling that those test point should be checked with a scope and they should show a certain wave.
I will give it a try later on, it is too hot to work in the garage for to long.

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

Not sure about the little transformers output winding location, but if they are the three pins at the left side, they all show 150 Ohms per side.
*150*150* it shouldn't be around 1000 Ohm? Maybe 500 x2?
BL_ERROR should indicate an inverter area problem, no?
Transformer or ccfl tube.
The 12V is there for a couple of seconds.
T-con voltage is missing because of this error, am I right?

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

I know I haven't taken pictures yet, I was busy with other repairs.
Nobody has any input?
I have another one for sale, should I just begin swapping boards?

[tom66]

Re: Sony KDL-46EX400 2 blink error code

Pictures are very useful in doing repairs have you done any further diagnosis than specified here?

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

Not yet, I'm just looking for some ideas, why the T-con would not get the 12V? Because of the protection mode that it is in?
I have tested all the inverter transformers and they are all 150 Ohms.(*150*150*)
I have tried testing the protection side of the transformers, but I can't measure those .2 AC/V as per the Youtube video.
How could I test the CCFL tubes?

[tom66]

Re: Sony KDL-46EX400 2 blink error code

T-Con ON is 0V so T-con 12V should be missing.

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

That's correct. This is what I'm trying to figure out, why.
There is an inverter error too.

[tom66]

Re: Sony KDL-46EX400 2 blink error code

Where is INV ERR?

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

BL_ERROR is 3.33V when the TV is on.

[signup]

Re: Sony KDL-46EX400 2 blink error code

When I plug it in, it would turn on(click only) and then off and would set a two blinking error code, which is the power supply board error.


What is interesting, is that I have replaced the main board with the other TV's bad board and it has the same symptom, 2 blink error code. Now I'm thinking, that main board is not bad after all? Why it was constantly clicking and now with this TV doesn't do that?
.

Hi

In the service manual it says that 2 blinks is the psu fault and this is probably why changing the main board has not changed the diagnostic blink

Wouldnt the self check system get clarification that the psu is at fault before self checking the main/tcon/inverter/panel thus giving it a 2 blink code regardless of whatever other boards you change.

Have you booted the psu as a stand alone to see if your voltages come up

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

Without the main board?

[signup]

Re: Sony KDL-46EX400 2 blink error code

Disconnect all the boards

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

It will start without the PS_ON signal from the main board?
Or should I use a resistor to start it up?

[budm]

Re: Sony KDL-46EX400 2 blink error code

It depends on the design of this power supply/inverter board, most newer one has pull-up resistor built-in so the main board will keep the PS_ON LO, when you remove the cable to the main board, the PS_ON will go HI when disconnected from main board. You have to look at the diagram to find out, most Samsung are done that way now.

[tom66]

Re: Sony KDL-46EX400 2 blink error code

Not exact but similar schematic

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

It doesn't boot by itself.

[tibimakai]

Re: Sony KDL-46EX400 2 blink error code

I have downloaded the 46EX402 and it's much closer to what I have.
It seems that Q6151 FET(TPC8119) doesn't output anything.
There is a resistor like IE 7A fuse, before it and there is 12.71V, but nothing comes out before the error kicks in.