Sony KDL-48W600B software update with no picture

[budm]

Re: Sony KDL-48W600B software update with no picture

If you are able to get 12V at the T-CON fuse, it means that the 12V switched MOSFET is getting the command from the processor to tun it on. How about other command Voltages to the power supply board?
If you disconnect the cable between T-CON and the LCD panel, do you get the AVDD, HVADD, VCC1.8, etc?

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

If you are able to get 12V at the T-CON fuse, it means that the 12V switched MOSFET is getting the command from the processor to tun it on. How about other command Voltages to the power supply board?
If you disconnect the cable between T-CON and the LCD panel, do you get the AVDD, HVADD, VCC1.8, etc?

With the interconnect cable detached the voltage is still gone from AVDD, HVADD and VCC1.8.

I will check those other command voltages and report.

[budm]

Re: Sony KDL-48W600B software update with no picture

At this point the switching power supplies on the T-CON are not working, I would inspect all the linear Voltage regulator IC' on that T-CON to see what you have on the inout and on the out, also the resistance with ref to GND for the input and the output of the regulators as well.
Upload good clear pictures of the T-CON board.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

T-CON board blended in to one pic hopefully it's good enough?

[budm]

Re: Sony KDL-48W600B software update with no picture

Oh, it is integrated T-CON.
BTW, since you have backlights which means the PS-ON, BL-ON and Dim control signals are present, so at this it is something on this T-CON that you need to test.
You can do resistance testing on those Voltages test points to see if any of them shows low resistance or not with ref. to GND. I suspect it has shorted MLCC similar to this one: SONY KDL-40W590, https://www.badcaps.net/forum/showth...ONY+KDL-40W590
BTW, do you see error blinking code? Probably not since the T-CON fuse did not blow.
I hope the FW update did not make the problem worst.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

Oh, it is integrated T-CON.
BTW, since you have backlights which means the PS-ON, BL-ON and Dim control signals are present, so at this it is something on this T-CON that you need to test.
You can do resistance testing on those Voltages test points to see if any of them shows low resistance or not with ref. to GND. I suspect it has shorted MLCC similar to this one: SONY KDL-40W590, https://www.badcaps.net/forum/showth...ONY+KDL-40W590
BTW, do you see error blinking code? Probably not since the T-CON fuse did not blow.
I hope the FW update did not make the problem worst.

Ok budm thank you for pointing me in that direction, I think I may have found something. I tested all the test points. The only one that makes the meter tone out (indicating near short to chassis, .015 reading) is the HVIN12V test point. Right next to that is an MLCC and I think a different kind of capacitor, both also checking the same reading across them.

[budm]

Re: Sony KDL-48W600B software update with no picture

Use meter on Ohm mode and report the readings in Ohms.
The '0.015' is that in Ohm on the meter with Ohm symbol?
You can try removing that CD100 to see if the low resistance will go away or not, so far I cannot see if there are any other caps connected in parallel with CD100 or not.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

Use meter on Ohm mode and report the readings in Ohms.
The '0.015' is that in Ohm on the meter with Ohm symbol?

12.8 ohms is the reading.

[budm]

Re: Sony KDL-48W600B software update with no picture

Remove that cap and see.
BTW, Diode DD1 is also connected basically in parallel with the cap via inductor LD1.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

Remove that cap and see.

This I will do, in the AM. If this cap is short can I test run the TV without it, just to see?

[budm]

Re: Sony KDL-48W600B software update with no picture

You need that filter cap.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

Cool, I'll pluck that cap and report.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

Remove that cap and see.
BTW, Diode DD1 is also connected basically in parallel with the cap via inductor LD1.

Removed cap CD100 and it is not short. Low reading across the neighboring inductor (LD01, .7ohms) and ICD2 (.5ohms) to the lower left. It looks like these two may be in parallel?

The caps below this inductor (CD14-17) don't indicate short in resistance but do have the same low reading across them in diode mode when measuring DD1 because it looks like they are in parallel. In one direction (.220.) and the other (1.118)

I'm going to try and find a datasheet for ICD2 and report back.

[budm]

Re: Sony KDL-48W600B software update with no picture

How about the resistance of Diode DD1?
All the test will be done in Ohm mode so we can easily see the resistance readings.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

How about the resistance of Diode DD1?
All the test will be done in Ohm mode so we can easily see the resistance readings.

In one direction it reads 7660ohms
In the other direction it reads 3350ohms

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

For means of comparison:

Interestingly enough, found in the parts pile is an older Sony t-con board (not integrated) that has a similar inductor, ICD2 number 58A and DD1 number B260A. The components are in different places but the circuit is fashioned similarly to the one I'm working on.

The parts pile board: (not the one in the TV I'm working on, this is just a comparison)

It's inductor also tests short (guessing this is how they ohms test)
ICD2 58A also checks short on the same pins (maybe because they're in parallel with the inductor?)

The only difference I see on the parts pile board is DD1 B260A only has electrical flow in one direction.

[budm]

Re: Sony KDL-48W600B software update with no picture

I look at your your pictures and come up with how the cap, inductor, and the diode are connected together so I would expect the diode DD1 will show about the same resistance as cap CD100, unless my assumption is not correct based on the pictures, you need to verify.
See if the place I marked with GND are actually tied together or not.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

I look at your your pictures and come up with how the cap, inductor, and the diode are connected together so I would expect the diode DD1 will show about the same resistance as cap CD100, unless my assumption is not correct based on the pictures, you need to verify.

Must I re-install cap CD100 before testing?

[budm]

Re: Sony KDL-48W600B software update with no picture

I updated the reply.
We are doing static Ohm test at this point, since the cap is not tested as shorts off the board then you can put it back in place. the shorts circuit is some where around that location, just a matter of tracing and finding it.

[DXseekerMO]

Re: Sony KDL-48W600B software update with no picture

CD100 re-installed. Across DD1 is about 3300ohms. Across CD100 is zero ohms.

UPDATE: From GND to GND in your pictures is the same 3300ohms