Dead As A Doornail. Sony KDL-40EX400

**budm** · 02-10-2015, 10:30 AM

Re: Dead As A Doornail. Sony KDL-40EX400

500 Ohms is fine, and you must remove the cable going back to the main board.

**Michale32086** · 02-10-2015, 10:38 AM

Re: Dead As A Doornail. Sony KDL-40EX400

Thanx, Budm...

I found a 430ohm resistor and plugged it in as pictured..

No response from the TV. Still doornail dead...

Did I select the right pins??

STBY 3.3v and POWER ON

Attached Files

**tom66** · 02-10-2015, 10:40 AM

Re: Dead As A Doornail. Sony KDL-40EX400

Picture is not clear enough to see if you've bridged the correct pins. What is the voltage now at POWER ON, with red meter probe on POWER ON and black probe on the chasiss of the TV? (Leave the resistor in place.)

**Michale32086** · 02-10-2015, 10:54 AM

Re: Dead As A Doornail. Sony KDL-40EX400

Originally posted by tom66

Picture is not clear enough to see if you've bridged the correct pins.

Yea, still looking for a nice hi MP camera...

Originally posted by tom66

What is the voltage now at POWER ON, with red meter probe on POWER ON and black probe on the chasiss of the TV? (Leave the resistor in place.)

Voltage at POWER ON is 3.27v with the resistor in place..

Attached Files

**tom66** · 02-10-2015, 11:00 AM

Re: Dead As A Doornail. Sony KDL-40EX400

Hmm. That should turn it on then. Can you remove the resistor and reconnect the
PSU and main boards. Then check power on pin again - just make a note if it goes high briefly then low, or not...

**Michale32086** · 02-10-2015, 11:07 AM

Re: Dead As A Doornail. Sony KDL-40EX400

OK, TV plugged in, POWER ON was at 3.3v...

I pulled the resistor and the meter went down to 0v...

Plugged the connector back into the Main Board. Meter read 1.9v for a sec or two, then went down to 0v

**tom66** · 02-10-2015, 11:13 AM

Re: Dead As A Doornail. Sony KDL-40EX400

To me this indicates your power board is bad. I think main board is trying to turn on board but failing. Put the resistor back in place and check voltage across the 450V cap Also try connectingpower on to gnd again with a resistor.

**Michale32086** · 02-10-2015, 11:22 AM

Re: Dead As A Doornail. Sony KDL-40EX400

Power to 450v Cap is 162v with resistor in place...

POWER ON to GND inline with the resistor??

IE POWER ON<===>RESISTOR<===>GND

**tom66** · 02-10-2015, 11:23 AM

Re: Dead As A Doornail. Sony KDL-40EX400

That's correct

**Michale32086** · 02-10-2015, 11:29 AM

Re: Dead As A Doornail. Sony KDL-40EX400

Still dead... STBY shows 3.3v POWER ON shows 0v

**budm** · 02-10-2015, 12:09 PM

Re: Dead As A Doornail. Sony KDL-40EX400

The power on pin is active high, so it needs >2.5Vdc to turn on.
Since the PFC Voltage booster did not come on with force on resistor, then you need more in-depth troubleshooting.
See PDF.
P/N of this power supply board?

Attached Files

**Michale32086** · 02-10-2015, 12:41 PM

Re: Dead As A Doornail. Sony KDL-40EX400

Originally posted by budm

the power on pin is active high, so it needs >2.5vdc to turn on.
Since the pfc voltage booster did not come on with force on resistor, then you need more in-depth troubleshooting.
See pdf.
P/n of this power supply board?

aps-54

Attached Files

**budm** · 02-10-2015, 12:49 PM

Re: Dead As A Doornail. Sony KDL-40EX400

Looks to be this one.

Attached Files

**Michale32086** · 02-10-2015, 12:52 PM

Re: Dead As A Doornail. Sony KDL-40EX400

That's it...

**tom66** · 02-10-2015, 01:00 PM

Re: Dead As A Doornail. Sony KDL-40EX400

Check DC volts across C6323, C6117, C6118, C6115 -- all on the primary side with PSON being wired HIGH. Can you also check if R6342 is intact (should be a short) and get the part # of IC6301 on the bottom of the board (the large multi lead chip)

Looks like IC6301 is an "all in one" main SMPS controller and PFC controller. I hope it is not a custom Sony part or getting a replacement may be tricky.

**Michale32086** · 02-10-2015, 01:11 PM

Re: Dead As A Doornail. Sony KDL-40EX400

OK, by PSON being wired HIGH, I assume you mean the resistor in place as before.

Not trying to be anal, but as Commander Spock would say, "Infinite reminders are infinitely preferable to gross errors"

As for R6342, it IS intact and DOES show a short..

IC6301 doesn't appear to have a part number on it.. which would argue for the idea that it's proprietary..

Attached Files

**tom66** · 02-10-2015, 01:19 PM

Re: Dead As A Doornail. Sony KDL-40EX400

Yes, POWER ON wired to STBY3.3V through the resistor. Try this trick to reveal part #: http://electronics.stackexchange.com/a/5410

**Michale32086** · 02-10-2015, 01:27 PM

Re: Dead As A Doornail. Sony KDL-40EX400

C6115 is dead... .000v

I am going to have to get under the board to check the rest.. It will take me a few...

**tom66** · 02-10-2015, 01:30 PM

Re: Dead As A Doornail. Sony KDL-40EX400

Usually, I find I can gently bend over the capacitor to probe the leads. (Only do this with power off -- the top of the cap is often live!)

**Michale32086** · 02-10-2015, 01:38 PM

Re: Dead As A Doornail. Sony KDL-40EX400

Originally posted by tom66

Usually, I find I can gently bend over the capacitor to probe the leads. (Only do this with power off -- the top of the cap is often live!)

Yea, I thought they were flush with the PCB.. They aren't..

OK

C6115 0v
C6117 14.29v
C6118 14.53v
C6323 14.28v

I'll try that trick with the IC as soon as I can dig up some chalk..

Dead As A Doornail. Sony KDL-40EX400

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