Sony KDL-32BX300 wont turn on

[Rodville]

I am trying to fix this for my brother. He was watching it and then it just went off no lighting strike no nothing it was just like it was switched off and won't come back on. It has no signs of life at all. No power lights, no relays clicking, no screen, nothing happens. I found this thread I found this thread https://www.badcaps.net/forum/showthread.php?t=31359 and he replaced his board and has some voltages. I have nothing at standby or BL ON until I unplug the cable going from the power board to the main board and then I get 0.59 and 0.58 respectively.

I know it's an old TV but I would hate to throw $50 for a power board on a $75 television just for it to not work. (I have read a lot of threads where it was the main board) and I can't justify that.

Is there any way to verify that it is indeed the power board at fault.

[dick_barton]

Re: Sony KDL-32BX300 wont turn on

Do you have any pictures of the circuit boards. Have you measured any of the voltages on the power supply?

[Rodville]

Re: Sony KDL-32BX300 wont turn on

I measured off the power supply board at the connector that goes to the main board.

Here is the board and I measured on the connector at the bottom left.


P.S. I checked the white use near the input and the two yellow ones near the bottom left connector.

[dick_barton]

Re: Sony KDL-32BX300 wont turn on

Could you list the Pin names and voltages on those pins
E.G.
Pin 1 5VSTBY 5.1V
Pin 2 12V 12.2V
etc

[budm]

Re: Sony KDL-32BX300 wont turn on

Could you list the Pin names and voltages on those pins
E.G.
Pin 1 5VSTBY 5.1V
Pin 2 12V 12.2V
etc

+1.
And if you can remove the connectors and take the pictures of the connectors so we can see the labels for each pin of the connectors that will be a big help, right now the wires are in the way.

[Rodville]

Re: Sony KDL-32BX300 wont turn on

[Rodville]

Re: Sony KDL-32BX300 wont turn on

Ok I rechecked it to make sure I was telling you guys the correct pins. The top two I am guessing (because the silk screening doesn't line up) are STBY 3.3v and POWER ON read 3.5V each. I plugged the main board back in and then I get 0.5V out of them. If I let it sit 10 min It will read 3.5v again. So I am now leaning towards the main board.

[dick_barton]

Re: Sony KDL-32BX300 wont turn on

Can you measure the following pins and add the missing voltages to them.

Tcon_On
Tcon_Vcc_12V
??
Dimmer
BL_On
BL_Err
12V
12V
Gnd
Gnd
AU_12V_Gnd
AU_12V
Power_On
ACOffDet
Stby3.3V

[Rodville]

Re: Sony KDL-32BX300 wont turn on

I get nothing on all the pins but the top two. At the voltages I stated before.

[dick_barton]

Re: Sony KDL-32BX300 wont turn on

Are you sure the top 2 pins which you give the voltage for are correct. I see STBY3.3V and ACOFFDET as the top two pins?

[budm]

Re: Sony KDL-32BX300 wont turn on

See the pin outs.

[dick_barton]

Re: Sony KDL-32BX300 wont turn on

Thanks budm for the confirmation that the top two pins are Stby3.3V and ACOffdet.

Rodville have you checked the two fuses alongside.

[anmol]

Re: Sony KDL-32BX300 wont turn on

remove socket to mother board and make a jumper at backside pcb with 1 k resistor as picture, (pin 1 to 3) stby to pwr_on
same way you can check back light on at jumper from stby to bl_on. (pin to pin 11}
check all voltage.

wbr

[Rodville]

Re: Sony KDL-32BX300 wont turn on

Thanks budm for the confirmation that the top two pins are Stby3.3V and ACOffdet.

Rodville have you checked the two fuses alongside.

I have checked the fuses and they are not blown.

anmol What do I look for with this jumper?

[budm]

Re: Sony KDL-32BX300 wont turn on

I have checked the fuses and they are not blown.

anmol What do I look for with this jumper?

What is going to happen with the two forced on resistors installed is that when you apply the main AC to the TV BACKLIGHTS should come on and stay on, and the DCV Between the legs of the main filter cap in the hot side should be closed to 400VDC.
The cable between the main board and the power supply board must not be connected for testing this forced on condition.

[Rodville]

Re: Sony KDL-32BX300 wont turn on

Sorry it took me longer to find the resistors than I thought it would.

Yes the backlight comes on and stays on.

[dick_barton]

Re: Sony KDL-32BX300 wont turn on

What is the voltage at BL_Err when in standby and then when the backlights are on when switched on as described in post #13

[Rodville]

Re: Sony KDL-32BX300 wont turn on

What is the voltage at BL_Err when in standby and then when the backlights are on when switched on as described in post #13

BL_Err is showing -0.01 on my meter.

Stby3.3V is showing 3.55

Power_On is showing 3.45

BL_On is showing 3.51

[budm]

Re: Sony KDL-32BX300 wont turn on

At this point it is the mother board problem, it is may be on the main board or something is stopping the main board from seeding the signals to the power supply board.
Did you already try without the T-con connected?
Btw, for sure you do not have standby Voltage when main board is connected.

[Rodville]

Re: Sony KDL-32BX300 wont turn on

How do I try without the tcon?