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

[DXseekerMO]

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

Disregard all of that.

Can someone please tell me what JL means, such as JL6109, JL6108 etc?

[R_J]

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

I can't be 100% but it could be jumper location, just a way to reference a board location to the schematic. JW means jumper wire
And NO YOU CAN NOT jump pins 4 and 26 of the ic, it will not end well

[R_J]

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

If you want to check the input to on pin 4 of ic6501 you will need a scope and an isolation transformer as the input is actually a square wave. If conditions are met, output pin 26 should be a logic high

[budm]

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

JLxxx are just the pads that can be used as test points.
For example: LED driver bd, see service manual page 44 and look at the PCB drawing and the picture here for example: https://www.shopjimmy.com/sony-a-180...blk-board.htm#
Pictures provided by shopjimmy.

[DXseekerMO]

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

Ok budm and R_J......

Let me first tell yous that I appreciate your help. I'm sorry I am such a poor student. I will be trying to understand and trace the problem down one more time today. If I am unable I will be giving up, and not because I want to.

I simply can't believe I'm considering giving up, and I'm super disappointed in myself for even thinking of throwing in the towel but I don't know what else to do.

This morning at 3:30 AM I was looking at the circuit diagram. Here's where I am now:

If I was reading the diagram right it looks like the VCC line comes from leg 5 of transformer T6201. Starting there I have 18V at resistors 6203 and 6204 and pin 4 of IC6201. I do not have VCC voltage anywhere else on that circuit.

Is this significant?

[R_J]

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

Not really, that is just the standby voltage circuit and we know it works because there is _18 volts on C6210 and also +4.7 on C6251 and +3.3 standby

The rest of the power supply will, and should be off. It requires the power_on voltage command from the main, it also requires the PFC_ON command from the main before the other circuits operate.

[budm]

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

Right now you need to get that AC_OFF_DET working, you can try replacing that IC or use the scope to look at the input AC feeding that IC , the spec sheet of the IC explain how it works and what the waveform looks like.

[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?

[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.

[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.

[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.

[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?

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.

[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.

[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?

"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.

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

[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?

[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.