Sony Bravia KDL-40EX400 Dead totally

[CraigR]

Let me state first that I have read all the other posts on this forum about this model and problem. Sony Bravia KDL-40EX400 dead with no lights or sound. I ran into this one other time and had good luck with a PS repair kit from shopjimmy.com so I ordered it and installed it and get the same. The kit included:
Fuses 1 F6101
Transistors 4 Q6301, 6302, 6303, 6304
Integrated Circuits 2 IC6101, 6301
Resistors 3 R6107, 6342, 6348
Diodes 1 D6308
No noticeably bad caps were seen.
So with that all changed I still get only 3v standby so next I put a 100ohm resistor between bl_on and standby and another between standby and PS_on this made the backlight flash on for less than a second then back off. and it would not do it again unless I waited a while like I needed to wait for a cap to discharge then I could get it to do it again. so now I'm not sure if I still have problems in the PS or inverter??

[tibimakai]

Re: Sony Bravia KDL-40EX400 Dead totally

Did you disconnected the wire harness, between the PS and mainboard?

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

Yes

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

Anybody??

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

I pulled all the caps and checked with ESR meter and all were good. I tapped of the main cap and when plugged in I get 390volts for a second then it drops or discharges. this is with the main board also disconnected and shorted harness Like checking for backlight.

[budm]

Re: Sony Bravia KDL-40EX400 Dead totally

OK, can you take good closed up pictures of the two white connectors with multi-wire on them so we can read the labeling of each pin.
Take the DC Voltage readings of each pin when TV power switch is NOT activated and when the power switch is activated.
Please list all the readings of each pin so we can see what are missing on which pin.

[Agent24]

Re: Sony Bravia KDL-40EX400 Dead totally

Did you check all the PSU outputs for shorts?

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

give me a bit for readings.

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

3.29v stby
2.7v ACOFFDET
3.2v Pwr_on
3.2v BL_ERR

Those are the only ones with power and no difference when pushing the power switch.

[budm]

Re: Sony Bravia KDL-40EX400 Dead totally

Why are your pictures mirrored image? Brighter pictures? I cannot read the labels.
"3.29v stby
2.7v ACOFFDET
3.2v Pwr_on
3.2v BL_ERR"
There are two connectors so which one are those readings are from?

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

The readings are all off the plug in the first pic.

[budm]

Re: Sony Bravia KDL-40EX400 Dead totally

https://www.badcaps.net/forum/attach...9&d=1415330345
Did you check that yellow fuse next to the connector?
Also what DC voltage do you get right at the two legs of the main filter cap in the primary side? It should be around 160VDC then jumps up to >350V when power switch is activated.
Does the voltage on the PWR_ON pin go down to <1V when is OFF?

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

Yes fuse is ok and the main cap is at 390 volts for a second when I plug the set in then slowly drops until about 167 volts it makes no difference pushing the switch it just stays at that until unplugged. Same with PWR_ON always stays at that 3volts and switch does nothing.

[budm]

Re: Sony Bravia KDL-40EX400 Dead totally

At this point, it is pointing to problem on the main board since that PWR_ON/OFF should toggle, at the same time there is error signal that are generated some where to kill the PWR_ON signal after the resistor R6223.
Also there is no any error code showing either. In other thread I saw that they fix it by updating the firmware but in their case there are error codes.
Training manual:
https://www.badcaps.net/forum/showpo...36&postcount=2

Also try disconnecting the cable to the T-CON board.

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

I'm thinking I would have taken the main board out of the equation since I disconnected it when I went to try to get the backlight to turn on.

[budm]

Re: Sony Bravia KDL-40EX400 Dead totally

So those readings are not when all the boards are connected?
Hook all the board back up but try leaving the T-CON out.

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

Those reading are with everything connected.

[budm]

Re: Sony Bravia KDL-40EX400 Dead totally

So did you try without the T-CON connected?

[CraigR]

Re: Sony Bravia KDL-40EX400 Dead totally

Yes, like in my first post the main was disconnected so that would mean the TCON was also disconnected.

[budm]

Re: Sony Bravia KDL-40EX400 Dead totally

But the T-CON board is the board by itself which is connected to the Main board, we need to have main board connected to the power suppl board but the white connector on the bottom left where the T-CON is attached to is to be removed.
https://www.badcaps.net/forum/attach...5&d=1414697633