Sony Bravia KDL-46XBR3 No display or sound

[x_orange90_x]

I just got an XBR3 that does not appear to be turning on. As soon as you plug it in the SONY logo and the green power light come on but the screen stays dark. Pressing the power button once gives a single blink of the power light and it remains on. Holding the button in for about 4 seconds causes the logo and the power light to turn off, but as soon as I let go of the button they come right back on.

I have an XBR4 that if I recall correctly has a very distinct relay click when you turn it on, however I'm not hearing that from the XBR3. I just got it yesterday and haven't had a chance to open it up and investigate, but I'm suspecting it may be bad caps on the power supply?

I've read about various board failures with this model causing no screen and sound, but I am not sure if that's the case here. I don't have any blink codes either, just a solid lit power light.

[x_orange90_x]

Re: Sony Bravia KDL-46XBR3 No display or sound

I checked a few voltages tonight. I only have a couple pictures of the boards and connectors because my camera sucks. Anyway, on the large plug between the main and psu I got 5v on the Standby pin, but only about 14.2v on the 18v pin. I also checked the 11v pins on the upper right hand side of the psu and only got about 9.5v on them.. And likewise, the 7v pins were around 6.7v.

The 11v pins on the D2 and D3 board connectors read roughly 9.5v also.

With the set "on" (green power light and white Sony logo), if I unplug the psu to main board connector everything cuts out, naturally. But if I plug it back in the power light and logo immediately light back up. It appears as if the main is either sending, or holding, an always on condition. What should I be looking at next?

[vinceroger69]

Re: Sony Bravia KDL-46XBR3 No display or sound

Link to service manual if needed

[x_orange90_x]

Re: Sony Bravia KDL-46XBR3 No display or sound

I checked voltages on several of the caps on the power supply board and all of them I checked were half voltage or less. For example the two large caps are supposed to be 450v and they were 175v, 16v caps we're reading at 8v, and a 25v read 10v. I had only the power plug and main board connector plugged in. Several of the pins on the main board plugs we reading less as well, for example a Standby 3.3v was reading 1.9v.

Am I possibly looking at a failed PSU, or is there a signal the main board is supposed to be sending that maybe it's not?

[vinceroger69]

Re: Sony Bravia KDL-46XBR3 No display or sound

I checked voltages on several of the caps on the power supply board and all of them I checked were half voltage or less. For example the two large caps are supposed to be 450v and they were 175v, 16v caps we're reading at 8v, and a 25v read 10v. I had only the power plug and main board connector plugged in. Several of the pins on the main board plugs we reading less as well, for example a Standby 3.3v was reading 1.9v.

Am I possibly looking at a failed PSU, or is there a signal the main board is supposed to be sending that maybe it's not?

Those voltage readings are odd firstly change your battery in your meter then i would test a 1.5 or 9v battery and make sure your meter is reading correctly and double check your meter is on dc volts

[x_orange90_x]

Re: Sony Bravia KDL-46XBR3 No display or sound

I will verify the meter and report back. Thanks Vince.