Sony KDL-46ex520

[Global Safari]

Hello Everyone,
I am new to the group and trying to figure out some voltages.I am in the
process of troubleshooting a voltage issue.I am trying to figure out where a certain voltage comes from.In the picture that I have attached it shows 12.35 volts at pin 1 of CN6001.My question is,that voltage generated from the main
board in the picture, or is it a direct voltage from my power supply board.
If so, where can I check to see this voltage on my power supply board.Power
supply board has no markings of voltage reference points. The tv I am working
on has no 12.35 voltage at that test point.

Thanks

[neilc6]

Re: Sony KDL-46ex520

The 12V for the tcon is generated on the power supply board and switched through the main board. You should give a more general description of the problem you are trying to fix and pics of the entire back of the tv and power supply board. The 12V will pass through a fuse on the tcon that should also be checked. Sonys typically flash diagnostic blink codes if you count the number of blinks.

[Global Safari]

Re: Sony KDL-46ex520

Hi,
Thanks for the reply.I have uploaded more pictures of the back showing the
boards.Led blinks 5 times then loops again.As I mentioned in the first thread
there is no 12 volts at that Pin..that 12 volts get sent to the T Con board.
Since that is not present, thats why I am getting the 5 blinks.

[nomoresonys]

Re: Sony KDL-46ex520

Do test #3 below since the board has no legend just put down the number of the pin followed by voltage in standby (tv plugged in but off) and the voltage when you hit the power button, maybe we can try to figure out what's up, might not be easy.

[Global Safari]

Re: Sony KDL-46ex520

Will do.Will be back soon. Thanks.

[nomoresonys]

Re: Sony KDL-46ex520

This sony probably has pullup resistors, try with tv unplugged from power, unhook cable from powerboard to mainboard, leave unhooked, plug power cord into powerboard, see if backlights come on and stay on, that is if they are not on at present.

[Global Safari]

Re: Sony KDL-46ex520

Okay..took voltages at standby by and with power on( found out that wire harness from main to power board has issues).


Also I tried the step in your last reply..no backlights

PIN 1 Standby PIN 1 Power on

O VOLTS DC 0VOLTSDC


PIN 2 PIN 2

0 Volts DC O Volts DC


PIN 3 PIN 3

3.3vdc 3.3 VDC


PIN 4 PIN 4


0VDC 0VDC


PIN 5 PIN5

3.3 3.3

PINS 6 -11 PINS 6-11
12.5 12.5

PINS 12-14 PINS 12-14

0VDC 0VDC


Left side is standby..right side is with the power button pushed. No change in voltages from standby to power on. Sorry for the numbers close to each other.

[nomoresonys]

Re: Sony KDL-46ex520

Ok, be CAREFUL on this test, with everything hooked up, it's testing the big filter capacitors on powerboard, looks like you have 3 of them, the ones that say 450 volt, KILLER voltage, with tv in standby meter on 600 dcv, negative probe on negative side positive probe on positive side, should get about 160 v in standby, then power up tv, should be about 400 v or a little less, only touch the capacitor legs with the meter probes, keep hands well away.

[Global Safari]

Re: Sony KDL-46ex520

I only have 2 on my board.In standby and power on, I get 393 vdc.
Scratching my head on this one.

[neilc6]

Re: Sony KDL-46ex520

Check for blown fuses on the main board.

https://www.badcaps.net/forum/showthread.php?t=66995

[Global Safari]

Re: Sony KDL-46ex520

Hi
Can you tell me from what I have tested does it point to the
main board?

[nomoresonys]

Re: Sony KDL-46ex520

Not sure, maybe check diodes D6602, D6603, D6604, so what's going on with the wire harness? do any of the connector ends look burnt, you can check it for continuity, just be careful not to expand the connector ends.

[Global Safari]

Re: Sony KDL-46ex520

On the power supply board or the main board?

[nomoresonys]

Re: Sony KDL-46ex520

Maybe check those big capacitors again with cable from powerboard to mainboard unhooked.

[nomoresonys]

Re: Sony KDL-46ex520

On the power supply board or the main board?

Unhook it from both and check harness for continuity from end to end.

[nomoresonys]

Re: Sony KDL-46ex520

I've used stripped bread ties to put in the ends, when meter probes are too big and to keep from stretching connectors out of shape.

[nomoresonys]

Re: Sony KDL-46ex520

Maybe check pin 3 and pin 5 again, with everything connected, see if one of them changes voltage when you toggle the power on and off.

[nomoresonys]

Re: Sony KDL-46ex520

Those diodes are on the powerboard.

[nomoresonys]

Re: Sony KDL-46ex520

If we knew what pin 1, 2 and 4 was for it would be easier or had a schematic.

[nomoresonys]

Re: Sony KDL-46ex520

Maybe take the powerboard out and check underside for bad/cold solder joints, sometimes they look ok but can be loose, look closely at anything on a heatsink and the transformer legs joints, they take the most abuse, be very CAREFUL not to touch the HOT parts, they can hold a BIG charge for quite a while.