Sony Bravia KD-50X690E blown resistor

[x_orange90_x]

I just picked up this tv yesterday and the previous owner said while watching tv he heard a loud a pop and then the screen went dark. I removed the back cover and found the source rather quickly; resistor R8601. A chunk of the ceramic had blown off exposing the inner wire. Due to the damage I cannot make out the colors of a couple bands. I likewise cannot find a datasheet for the power supply. I tried pulling up pictures of the same board online but the resistors have different colored bands which I half expected as I've had this happen before.

The power supply is 715G8413-P01-001-0H2S (PLTVHY401XACB).

Attached are photos of the board and the resistor. Hopefully someone can help me identify the resistor's value. Thanks!

[lotas]

0.1 Om 1%

[x_orange90_x]

0.1 Om 1%

That was quick! Thanks for the reply! Can you tell if this resistor critical, or might I be able to replace it with one of different value? Is it likely that it simply failed on it's own, or should I suspect another component as well?

[lotas]

No, you need to install it like this, it's a current resistor, it doesn't just burn out, check the nearby transistor.

[x_orange90_x]

No, you need to install it like this, it's a current resistor, it doesn't just burn out, check the nearby transistor.

Ok I will check the two transistors nearby. Thanks!


Would this resistor be suitable?

uxcell 15 Pcs Axial Lead 1% Tolerance Metal Film Resistor 0.1 Ohm 2W https://a.co/d/h0zLk6O

[lotas]

Ok I will check the two transistors nearby. Thanks!


Would this resistor be suitable?

uxcell 15 Pcs Axial Lead 1% Tolerance Metal Film Resistor 0.1 Ohm 2W https://a.co/d/h0zLk6O

Yes.

[x_orange90_x]

Update: I am now worse off than when I started. 😮💨

A couple days ago I got my pack of resistors and decided since I had an excess of them, I would replace just that and give it a shot. As expected, the new one popped immediately upon plugging in the tv. So last night I replaced it again as well as a nearby transistor. The transistor had continuity between all 3 legs so I assumed it was completely shorted. The identical one next to it has continuity between Source and Drain pins, which I don't *think* it's supposed to? I didn't have an exact match so I went with a higher voltage one from another board. After plugging the tv back in the resistor did NOT pop, so that solved that I suppose. I had a green standby light but the tv still will not power on.

After a few minutes of unplugging/replugging cables I no longer have the green standby light 😒. Everything is plugged back in snug.

What's strange is the transistor I used as a replacement had no continuity between it's legs before I installed it, and after being put on the board it has continuity between ALL 3 legs just like the old one. If it were actually shorted the resistor should have blown again, right? Is it possible the other transistor having continuity between Drain and Source is causing a problem for the one next to it which I replaced? I have another identical to the one I used, so I could replace the other one if advised.

In the attached photo you can see the 2 transistors and the resistor. The upper transistor is the one with the Source-Drain continuity, and the bottom is the replacement that is NOW showing continuity between all legs. I also checked that diode and it is good.

[nomoresonys]

Any continuity between legs equals bad, remove both and test out of circuit, probably will still show continuity which means bad, don't replace with new ones til you figure out what's wrong. A dim bulb tester saves a lot of money and time, the bulb lights up instead of blowing the components.

[x_orange90_x]

Any continuity between legs equals bad, remove both and test out of circuit, probably will still show continuity which means bad, don't replace with new ones til you figure out what's wrong. A dim bulb tester saves a lot of money and time, the bulb lights up instead of blowing the components.

Is it possible the one with continuity between only drain and source caused the second one to fail, then subsequently the resistor that blew? What are the chances I have two bad transistors? I'm guessing pretty good IF something else caused them both to short, but what?

I think I'll remove the other suspect one and see if my replacement will stop having continuity. Maybe it's in a half open state or something? I don't know, electronics are weird 🥴

[R_J]

The drive ic U8501 is damaged, there may be other components in the gate drive that are also damaged. a short between drain and source will supply 160vdc to U8501.

[x_orange90_x]

The drive ic U8501 is damaged, there may be other components in the gate drive that are also damaged. a short between drain and source will supply 160vdc to U8501.

Oh so I'm better off buying a new board then.

[nomoresonys]

I think by the time you have to spend testing to see if anything else besides the IC is bad, then you have to replace them without messing anything up, then usually have shipping and tax, a replacement board could be the lesser of the evils: https://www.ebay.com/itm/38700745809...Bk9SR_aLk8KbZA

[x_orange90_x]

I think by the time you have to spend testing to see if anything else besides the IC is bad, then you have to replace them without messing anything up, then usually have shipping and tax, a replacement board could be the lesser of the evils: https://www.ebay.com/itm/38700745809...Bk9SR_aLk8KbZA

That's exactly the one I was considering buying!

[x_orange90_x]

The drive ic U8501 is damaged, there may be other components in the gate drive that are also damaged. a short between drain and source will supply 160vdc to U8501.

I went to remove the other transistor and found something I missed. C8611 looks to be in bad shape. Could this be the reason the transistors blew?

Also, shouldn't the resistor that blew protect the IC?

[nomoresonys]

Woah, how did you miss that? Sometimes they just blow, I would build a dim bulb tester for a few bucks in parts, simple build, there's probably 100 how to videos on youtube, but remember the IC is most likely bad like RJ said. Replace blown parts and try it, if the bulb lights up bright and stays lit then there's still a problem. If it lights for a second or two then goes out or very dim then it's probably ok to plug tv back into strip or outlet and try it.

[R_J]

If you look at Q8601 The drain is connected to +160vdc via R8601, if the mosfet shorts D-G-S 160vdc gets fed to the ic through the gate resistor R8613,R8612 and also the source is connected directly to the ic, so it is possible it survived the voltage but who knows for sure. Post the ic number and we can look up the datasheet to see the pin max voltages.
C8611 is across Q8602 D~S so when the cap shorted, it likely caused Q8601 to short as well. replace the cap with a 2kv type of the same capacity

[x_orange90_x]

I've replaced all of the following:

C8611
C8613
Q8601
Q8602
R8601
250V 5A Fuse

I get a green power light that stays solid but no backlights or image (with flashlight). I also have a red light in the optical port. I checked the voltages on C9801 and C9802 and they are at a steady 390V. With the main board disconnected I do not get backlights either. I previously tested the backlights with my LED tester and they appeared to work fine. .

[nomoresonys]

Might be that IC then, did you do as suggested in post #16.

[x_orange90_x]

Might be that IC then, did you do as suggested in post #16.

When I'm back at home I'll try to get the number on the IC.

[x_orange90_x]

R_J attached is a photo of the IC U8601.