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

[budm]

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

Right now we need to find out why AC_OFF_DET line goes to <1V when main board is connected and need to verify the stby3.3v pin with main board connected is at 3.3V or not, if 3.3V is much higer than 3.3V that can be problem.

NJM2884-33 is 3.3V (Vo of +/-1% ) LDO regulator, so are you sure your are getting 3.3V at the STBY3.3V pin of the power supply connector when main board is connected, or you are getting close to 4V or higher?


Ah found your post #24:
"There was 4.45V at the stand-by pin of CN6001 that became slightly unstable but returned to 4.45V and remained". So that NJM2884 is bad.
Long thread is hard to keep track of the Data.

[DXseekerMO]

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

Right now we need to find out why AC_OFF_DET line goes to <1V when main board is connected and then verify the stby3.3v pin with main board connected.
NJM2884-33 is 3.3V (Vo of +/-1% ) LDO regulator, so are you sure your are getting 3.3V at the STBY3.3V pin of the power supply connector when main board is connected, or you are getting close to 4V or higher?


Ah found your post #24:
There was 4.45V at the stand-by pin of CN6001 that became slightly unstable but returned to 4.45V and remained. So that NJM2884 is bad

When I measure between pins 7 and 9 on CN6101 I get 3.48V with CN6101 attached to the PSU and the main board installed

[DXseekerMO]

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

[/B]:
"There was 4.45V at the stand-by pin of CN6001 that became slightly unstable but returned to 4.45V and remained". So that NJM2884 is bad.
Long thread is hard to keep track on the Data.

This was with CN6101 unhooked from the PSU EDIT and reference chassis ground

[budm]

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

Njm2884.
On page 9 graph it shows example of the 3V version with Zero Io mA and it still maintains 3V output, so at this point I would change out that 3.3V regulator.

[DXseekerMO]

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

Thank you budm, I will order that today and get it coming, and thank you so very, very much for hanging in there and for helping me out.

R_J: Thank you very much for all the help and direction throughout this process and for hanging in there.

Again I apologize for my causing this whole thing to drag out. I sincerely appreciate both of you.

[DXseekerMO]

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

You would use chassis ground or pin 1 of cn6002, You can find out which resistor it is by puting a probe on CN6002 pin 9 and check to each of the 4 resistors of RB9031. the point that is 0Ω is pin8, now check the other side (pin7) of the resistor to ground, that will check the input point (AE5) of the ic9000

Njm2884.
On page 9 graph it shows example of the 3V version with Zero Io mA and it still maintains 3V output, so at this point I would change out that 3.3V regulator.

So a couple days ago NJM2884 arrived here from the parts store. I plan to install it today and hopefully we can get some magic to happen!

[DXseekerMO]

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

NJM2884 installed, 3.25 to 3.28V is present regardless of whether or not CN6101 is plugged or unplugged. There is still no stand-by light.

At this time I think I am going to start a new thread on this same TV. Reason being is I made such a mess out of this thread I think it would avoid a lot of back tracking and confusion moving forward.