Trying to Save - SONY BRAVIA KD-75X780F - No Picture BUT there’s sound

[KYBOSH]

from one point you want to learn... that's fine.... but did you know any attempt to work or fed V at wrong area, you will kill many other parts... so why we do spend.time to help you and we do read how you are going to kill the set ? better leave you and laugh !!! NO this no one serious man man will do it-

you can read on the area i show you F and in general F are fuse .

Thank you again!
I checked all of the fuses in this section and indeed all the fuses on the board and they were all intact and read as continuous.
I then proceeded to check each component around those 2 ICs. I checked for both continuity and measured their resistances.
Here is what I found:


The there were several resistors (marked in red) around IC4002 reading as shorted (MM ringing tone) in circuit and their resistance were low (~47Ω).
Seeing how none was completely shorted Im guessing there may or may not be a problem with that IC there (W25Q32JV).

It may just need to be reflashed and not replaced. Either way i will need the dump for this chip if it is indeed the problem.
Searching for it now!

[Diah]

t IC there (W25Q32JV).

It may just need to be reflashed and not replaced. Either way i will need the dump for this chip if it is indeed the problem.
Searching for it now!

dont play with these IC content...
leave the heatsink out and put the MB back in TV....turn on then measure both IC Pins 8 V., and other pins with reference to TV chassis.... keep your eyes on the screen if it show any sign during your messurments

[KYBOSH]

dont play with these IC content...
leave the heatsink out and put the MB back in TV....turn on then measure both IC Pins 8 V., and other pins with reference to TV chassis.... keep your eyes on the screen if it show any sign during your messurments

Interesting results but maybe normal / to be expected.



At certain pins (pin 2,3 and 5 of IC 4002) the voltage fluctuates as low as 0v to as high a 2V+.
But more interestingly if you hold the test leads these pins form more than 5 seconds or so the TV shuts off and gives 8 Red Blinks.
The panel itself never displayed anything on the screen though.

[Diah]

IC 4002 PiQ are fine and active to sync any change of currents... so the circuit of IQ 400 working
but FRC one IC 4201 complete out of business .
check the surface of the huge black IC which downside the MSTAR... see the surface under loop if it broken some where

[lotas]

Interesting results but maybe normal / to be expected.



At certain pins (pin 2,3 and 5 of IC 4002) the voltage fluctuates as low as 0v to as high a 2V+.
But more interestingly if you hold the test leads these pins form more than 5 seconds or so the TV shuts off and gives 8 Red Blinks.
The panel itself never displayed anything on the screen though.

The power fluctuates and data is being exchanged; such experiments can easily damage the firmware inside this chip (this is done using an oscilloscope, not a multimeter).

[Diah]

The power fluctuates and data is being exchanged; such experiments can easily damage the firmware inside this chip (this is done using an oscilloscope, not a multimeter).

for once will not harm at all

[Diah]

nwxt dont touch IC 4002 PiQ again...
all points marked with red measure volts from both side while TV on.... control too the temperature of the MSTAR SoC.. i do believe there are open circuit some where

[KYBOSH]

IC 4002 PiQ are fine and active to sync any change of currents... so the circuit of IQ 400 working
but FRC one IC 4201 complete out of business .
check the surface of the huge black IC which downside the MSTAR... see the surface under loop if it broken some where

No signs of damage here.

nwxt dont touch IC 4002 PiQ again...
all points marked with red measure volts from both side while TV on.... control too the temperature of the MSTAR SoC.. i do believe there are open circuit some where

Nothing out of the ordinary.
Voltage on both sides of all 0Ω resistors and fuses in the vicinity.


Note: Gotta thank you (and the rest of you guys) for taking the time to guide me here. Very much appreciated!

[KYBOSH]

The power fluctuates and data is being exchanged; such experiments can easily damage the firmware inside this chip (this is done using an oscilloscope, not a multimeter).

Friend, in terms of probing and measuring what is the difference between a multimeter and an oscilloscope?
Does a multimeter send feedback/voltage or signal back into the thing being measured?

[lotas]

Friend, in terms of probing and measuring what is the difference between a multimeter and an oscilloscope?
Does a multimeter send feedback/voltage or signal back into the thing being measured?

Internal resistance, internal capacitance, shielding...

[Diah]

you didn't report back on the MSTAR Temperature ?
let go back shortly to the T-CON... let see why there are no sync from MB SoC to it... we start with PMIC measure all this 5 points while set on , always yours eyes on the screen to see if there any sign

[Davi.p]

OK watch this pic, on top of the connector there are 6 test points, the third and the fourth one are FB_VRD and VRD (pay attention not VRB), i think thery are a control loop for the integrity of the gate drivers, VRD is the loop start, FB_VRD is the end, so check both in voltage, for the FB331/332 check also the voltage

[KYBOSH]

Internal resistance, internal capacitance, shielding...

Thank you very much for this. I have an old scope in need of repair what I have been delaying for months.
You just gave me motivation to get it back ON my workbench from UNDER my workbench!

you didn't report back on the MSTAR Temperature ?
let go back shortly to the T-CON... let see why there are no sync from MB SoC to it... we start with PMIC measure all this 5 points while set on , always yours eyes on the screen to see if there any sign

As Requested. Eyes on the screen. No signs of display life.

OK watch this pic, on top of the connector there are 6 test points, the third and the fourth one are FB_VRD and VRD (pay attention not VRB), i think thery are a control loop for the integrity of the gate drivers, VRD is the loop start, FB_VRD is the end, so check both in voltage, for the FB331/332 check also the voltage

And the voltages for both 331 & 332 is 3.3V.

[Diah]

As Requested. Eyes on the screen. No signs of display life..

where are the reset of yours measurements off the 5 points i asked?

[Davi.p]

For your information, "Legend" is an automated tag that the new forum gave to all user with a.certain amount of posts, including me, but i prefer not to use that term, there are users that are far far from a legend, one can be a poor obsessed that do nothing useful in life and his name his legend.. !! :+/
For the rest of that certain user, are also delirium, i will not also report it to the staff that has full the low parts of these stories.. let's go on, and decide yourself who deserves attention..

[KYBOSH]

where are the reset of yours measurements off the 5 points i asked?

I added the voltages to your pic. Just click. On the picture above my response.

Also regarding the temperature of the ofchip I felt it with my finger and it was not hot and i kept checking it every minute or so. it stayed cool for about five minutes. it started to get warm/hot at around the 5 minute mark.But by then I was done so I just unplugged the tv set.

[Diah]

I added the voltages to your pic. Just click. On the picture above my response.

nothings here or there dont make it complex other wise i will never ask

[Davi.p]

And the voltages for both 331 & 332 is 3.3V.

but the other two points?

[lotas]

Also check the resistance relative to gnd t-con of these points (CKV1- 6 (there are 12 points in total)) with the panel connected (two cables connected), then with one cable disconnected and with the second cable disconnected.

[Diah]

For your information, "Legend" is an automated tag that the new forum gave to all user with a.certain amount of posts, including me, but i prefer not to use that term, there are users that are far far from a legend, one can be a poor obsessed that do nothing useful in life and his name his legend.. !! :+/
For the rest of that certain user, are also delirium, i will not also report it to the staff that has full the low parts of these stories.. let's go on, and decide yourself who deserves attention..

are you sick or you realty think you are David.P the criminal we do know... are you planning to turn this user T-CON a part for yours previous experiment with yours land man when you drive him to make his PSU like hot air fried crispy kitchen machine...