Sony Bravia KDL-37v5810 Power Fault

[Easky15]

Hi, I have here a 37 inch sony kdl-37v5810 when the tv is powered on its just a black screen with no backlight and the green light is on and flashes when buttons are pressed but no sound so don't think set is powered up fully, I read the dc voltages and the only one which seemed a bit strange was the 15v read as 17.8v, I then unpluged the cable going from the inverter to the main board and tried to power it then i got a backlight with black screen, Does this sound like a main board or a power board fault? Recieved my DCA55 today so hopefully that might help fix it. Still waiting on my fluke 87 arriving.. :-)

A few pics added that might help

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

Anyone know how i further test this tv??

[budm]

Re: Sony Bravia KDL-37v5810 Power Fault

Post good clear pictures of the back side of the TV so we can see what we are dealing with.

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

Post good clear pictures of the back side of the TV so we can see what we are dealing with.

Hope this helps..

[budm]

Re: Sony Bravia KDL-37v5810 Power Fault

OK, you need to remove that black cover off the Inverter board, remount the board with out the cover, then you have to measure the voltages and signals at that white connector on the Inverter board. Aslo post good clear pictures of the inverter board especially around that white connector.
You should read Basic LCD TV troubleshooting guide.

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

I wrote a reply to you ages ago but must have forgot to hit send, Sorry.. ;-) Voltages on pins 1-5 VDD on inverter board is 24.81 DCV, also getting same 24.81 both sides of f2 and f3, tested f1 on the t-con and not getting any voltage there either side,

[budm]

Re: Sony Bravia KDL-37v5810 Power Fault

OK, to the right of the Inverter board connector CN1, you can see big fuse F3 (F5A /125V), next to that fuse is small black fuse that looks like resistor, it is F1 (F 0.16A/30V), check and see if that fuse is open, it should have 24VDC at both ends of the fuse measure it with ref to the chassis ground.

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

OK, to the right of the Inverter board connector CN1, you can see big fuse F3 (F5A /125V), next to that fuse is small black fuse that looks like resistor, it is F1 (F 0.16A/30V), check and see if that fuse is open, it should have 24VDC at both ends of the fuse measure it with ref to the chassis ground.

Yep , Gettin 24.81v either side of f1 fuse.. ;-)

[budm]

Re: Sony Bravia KDL-37v5810 Power Fault

Pin 12 is the BL_ON pin, what DC do you get there, it should be >2VDC? so far your power supply is good.

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

Pin 12 BL_ON reads 0.029v

I think i mentioned before the only strange voltage from the psu is the 15v which reads 17v

[budm]

Re: Sony Bravia KDL-37v5810 Power Fault

OK, so the main board is not sending the BL_ON, but the PS_ON is OK because the 24V is on. You also not getting the the 12V to feed the T-CON which is also switched on by the main board to turn on the MOSFET on the main board that feed the switched 12V to the T-CON. Reading of 17V on 15V is not big deal right now, that 15V may not be regulated power supply for probably the audio amplifier circuits.
It looks like big troubleshooting time for the main board.

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

I have all the gear hear to fix it just not the know how, I now have a dca55 and fluke 87 so hopefully they'll help, ;-)

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

might help

[budm]

Re: Sony Bravia KDL-37v5810 Power Fault

I myself never fix the main board down to component level unless it is simple thing like bad regulators (VIZIO).
I cannot find the service manual on ELEKTROTANYA either. You can inspect the main both sides real well to see if it has any burnt/damaged components, check regulator and switching supplies, etc.

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

Ok no worries, Thanks again for your help mate, Might just go ahead and buy a replacement main board,

[aar5384]

Re: Sony Bravia KDL-37v5810 Power Fault

Sorry to jump in on this, but i have one of these exact same tv's with the same problem but with an error code..

Mine appears to power up with the green light and press the buttons and it just blinks the green light, however after about 20 seconds the green light goes out and the centre red light starts to blink 8 times pauses then repeats, is this the same or something else?

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

UPDATE.. Just fitted a replacement board and still got the same fault.. Could anyone suggest how to further troubleshoot this set or which other board i should replace next??

[selldoor]

Re: Sony Bravia KDL-37v5810 Power Fault

Follow post 1 to 11 and redo any tests and post the results - if budm couldnt come up with anything you might be stuck - was the board a new one or an untested pull.

[budm]

Re: Sony Bravia KDL-37v5810 Power Fault

So the BL_ON line is still stuck LOW? Main board is the one that generate this signal. Do you still get 24VDC to inverter?

[Easky15]

Re: Sony Bravia KDL-37v5810 Power Fault

BL_ON still reading 0.029v and yes still getting 24v at the invertor, The board is used from ebay but the seller says it was pulled from a set with a cracked lcd...? and everything else was working when he removed it..