Sony KDL-55EX620, no stand-by volts from one bad resistor?

[DXseekerMO]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

+1

I was so busy typing and looking at the schematic I didn't see you jump in there. Thanks budm

[DXseekerMO]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

Ok I looked at the board. It looks like I can test collector voltage at one side of R6307, on top of the board. I see no way to test base voltage from the top of the board.

The board needs to be screwed down so it is grounded, correct? If so how am I going to test base voltage?

Thanks for hanging in there R_J

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

when the conditions of ac detect of ic6501 are met pin 26 logic is high. Since vcc of that ic is ~18 volts i would believe +18 on pin 26 would be considered high,
ph6302 (led) is off, transistor between 3 & 4 open, q6402 off (open) +3.3 applied through r6403 and r6404 to ac_det_off = 3.3 volts.
If you are getting 0 volts on ac_det_off, q6402 could be shorted.

+1

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

So +18 volts on pin#2 of the opto = +18 on pin 26 which is not low but high
So AC_OFF_DET should be 3.3 volts?

Yep, that is what should happen.

[R_J]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

Q6301 is the switch controlled by the power on opto, you could diode check it or check the voltage on the base and the collector
Its collector connects to pin 28 of IC6501
Mode select input
GND connection: Normal sequence
VCC connection: Standby mode

[DXseekerMO]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

Ok here's what I see when looking at my board:

Q6301 is the one that looks crispy. I think it is on the primary side of the board.

[R_J]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

When the conditions of ac detect of ic6501 are met pin 26 logic is HIGH. Since VCC of that ic is ~18 volts I would believe +18 on pin 26 would be considered HIGH,
PH6302 (led) is off, transistor between 3 & 4 open, Q6402 off (open) +3.3 applied through R6403 and R6404 to AC_DET_OFF = 3.3 volts.
If you are getting 0 volts on AC_DET_OFF, Q6402 could be shorted.

[DXseekerMO]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

I think we need to clean slate and start it over.

Ok guys, I have asked for and monopolized a heck of a lot of yous time, and all for naught because of my poor understanding and information. I am really sorry for this.

For my poor information and wasting of everyone's time I wouldn't blame either or both of you for bailing out. You all are gracious and kind.

Here's your chance to bail, no hard feelings.

I thank both of you for what you have done. You all are troopers for sure.

[DXseekerMO]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

OK, I read through the thread and see this one indicating 0V on pin 3 of the OPTO, so that means the Opto is not ON! so the AC_OFF_DET line should be high right now. But then again I am not sure at this pint which info is right, which info is wrong.

I hope my post before this one clears things up?

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

I think we need to clean slate and start it over.

[R_J]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

So +18 volts on pin#2 of the opto = +18 on pin 26 which is not low but high
So AC_OFF_DET should be 3.3 volts?

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

"I am unable to find a test point on the top side of the board for PIN26 of IC6501. I was using leg 2 of PH6302 as I traced that leg to PIN26 to give the PIN26 measurement. Voltage across pins 1 and 2 are zero. When I test PIN2 on PH6302 to hot ground I get 18V, also get 18V on PIN1" That means the OPTO is not on.

[DXseekerMO]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

What is the voltage on pin 26 of IC6501? (remember use hot ground) I would also check the voltage across pins 1 & 2 of PH6302 AC DET optocoupler.

I am unable to find a test point on the top side of the board for PIN26 of IC6501. I was using leg 2 of PH6302 as I traced that leg to PIN26 to give the PIN26 measurement. Voltage across pins 1 and 2 are zero. When I test PIN2 on PH6302 to hot ground I get 18V, also get 18V on PIN1

Replacing the IC will be the easiest (Shopjimmy sells the IC so it may be commonly failed part), or you can force AC_OFF_DET signal line HIgh to fool the main board that the AC_OFF_DET is OK to see if the TV will work properly or not.

How does one force the AC_OFF_DET signal line high?

I believe he reported as LOW (FAULT condition, so the LED in the Opto is ON = LOW AC_OFF_DET to the main board).
It should be HIGH if there is no fault condition.

I may have measured that and reported low because I was using chassis ground when taking the measurement. At PH6302 I have 18V on pins 1 and 2 when measured using hot ground

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

So I am frustrating myself and I have made a mistake. I am getting things transposed.

What you all don't know is about 20 years ago I was seriously injured by a 6500 pound truck on a supposed 10,000 pound rated lift which folded under the weight and came down on top of me. Turns out the cheap lift was over-rated. Of the many injuries I had, I also had a head injury and sometimes this causes me to get things backwards.

I died on that shop floor. I wouldn't be here if it wasn't for the service manager knowing what to do.

Sometimes I feel like "Cousin Eddie" on National Lampoon's Christmas Vacation. Rev up the microwave, piss myself and forget who I am for a while.

I don't mean to do it. It happens on automatic pilot and I'm none the wiser....least for a bit anyhow.

Pin 4 of PH6302 has 3.45V
Pin 3 has zero volts.

OK, I read through the thread and see this one indicating 0V on pin 3 of the OPTO, so that means the Opto is not ON! so the AC_OFF_DET line should be high right now. But then again I am not sure at this pint which info is right, which info is wrong.

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

In which post was that? I could not find where he supplied pin 26 voltage

I believe he reported the Voltage reading on pin 2 (Cathode) of the Opto.

[R_J]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

In which post was that? I could not find where he supplied pin 26 voltage. He was using cold ground for all measurements up to post #35

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

What is the voltage on pin 26 of the ic? (remember use hot ground)

I believe he reported as LOW (FAULT condition, so the LED in the Opto is ON = LOW AC_OFF_DET to the main board).
It should be HIGH if there is no fault condition.

[budm]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

Replacing the IC will be the easiest (Shopjimmy sells the IC so it may be commonly failed part), or you can force AC_OFF_DET signal line HIgh to fool the main board that the AC_OFF_DET is OK to see if the TV will work properly or not.

[R_J]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

What is the voltage on pin 26 of IC6501? (remember use hot ground) I would also check the voltage across pins 1 & 2 of PH6302 AC DET optocoupler.

[DXseekerMO]

Re: Sony KDL-55EX620, no stand-by volts from one bad resistor?

I'm unable to source an oscilloscope, right now anyways. That being the case I need to replace that IC and see what happens? Are there any substitutions a o-scope that might get me by?