How to Troubleshoot Power Supply with no Standby voltage. Sony KD 70x690E led TV repair.

[@danielisaac2203]

Far and few are able to convey knowledge . More importantly actually make the experience comprehensive Love your work. Cheers!

[@adburnett42]

Wow! THANK YOU! found a free broken 70" Sony TV propped up against a tree. Found your video. Followed the instructions and replaced the two diodes. TV WORKS GREAT!!! THANK YOU!!!!

[@makingthingsreal101]

Neat trick to bypass the optocoupler and verify that the problem is somewhere in that feedback circuit. This is the kind of thing I most enjoy learning.

[@louf7178]

That's a deep understanding of the circuits with amazing casual manipulation. The only thing I could relate to is that the voltages should be stable; I think I've confidently ruled out my power board. Thank you.

[@Mechsounds]

Hello from Melbourne. Your repair video came just at the right time. I was given a 60 inch Sony with exactly the same fault. Thanks to you the set has been saved from going to landfill. You have inspired me to use my electronic background more. Keep up the great work.

[@bigdog8882]

EXcellent! Make sure you check out the Course too. bigdogtvrepaircourse.mykajabi.com/

[@bindardondat5292]

Great to watch a professional work his magic. Wish I had this knowledge before spending $200 on parts for a Smart 58" tv that I couldn't get to come on. New main board, power board, & T-com board did nothing. Worst part is, Jimmy's tv won't take the parts back.

[@zakhanpanayus1160]

I enjoyed this I still don't have a good understanding on all of it because my board still don't work but I thank you did and excellent lesson

[@StaggerLeex]

You are born for a teacher. Thank you.

[@jefftoll604]

Excellent repair video. Replacing the optocoupler with a diode is an amazing technique.

[@winisrt6284]

yes, your testing is very keen on the board and traced the power fault accurately thanks to your theory.

[@FranciscoRios-gt2nb]

Thanks!

[@abelabner]

Thanks for sharing your knowledge! Your explanations are great and well explained. Thanks much!

[@MikeRock-r4w]

Thanks! So why did the diodes go in the first place Bigdog?

[@bigdog8882]

Just component failure.

[@nb4582]

Great video, loved your debug process :) Helped me fix my parents TV too which is awesome, thanks!

[@Trucam2020]

Excellent repair video. Thanks 👍

[@alcobia09]

Excellent instruction... just found this video. Thank you for the post.

[@d614gakadoug9]

As soon as it was determined that Vcc for the IC was pulsing, having already determined that the 5 volt output didn't, it was almost 100% certain that the fault was a short circuit on the main output winding of the flyback inductor ("transformer"). The pulsing of Vcc would be due to the charging of the Vcc cap from the primary-side start-up circuit (internal to the power IC or external with some ICs). A short on the main output would not influence that. Because the voltages on the secondary side of the inductor track each other, if a short existed on the main output, Vcc would not be maintained from the auxiliary winding which would not be producing any useful voltage. When diodes are used in parallel it is important to be sure they are as close to identical as possible. Both/all should be replaced with the same type number from the same batch (not always easy to determine) from the manufacturer. If they are not well matched, the one with the lower forward voltage will "hog" current, run hotter, its forward voltage will drop even further and it will hog even more current as a result. Paralleling two diodes in the same package is generally much "safer" because they are both on the same die and likely inherently quite well matched. This is fairly common in higher power outputs of switchers. I highly recommend E-Z-Hook products for clip leads for small spaces. There are lots of choices. They don't easily come loose like alligator clips do. A loose alligator clip can cause a disaster.

[@doudoupoupon]

De très bonnes explications, très intéressant ! Gros bisous de France ❤

[@kenpappas9520]

what happened to that shorted capacitor that was next to the failed diodes?

[@nab6026]

i cant buy the SR5150 diodes in my area. Can you give me a few reccomendations fro other? Also can you tell me the minimum forward voltage, current and reverse voltage required for these diodes?

[@wisher21uk]

Brilliant fix mate nicely done 😊

[@bigdog8882]

Thank you! Cheers!

[@jeffcaidler572]

Hi ,love your videos and your setup.. I have a Sony Xbr65x850g ,i have 6 blink red light ,white screen , no sound ,Theoptical input shows power on mainboard ,Not sure where to start testing . Im stumped .

[@bigdog8882]

6 red blinks on Sony usually means you have bad led strip(s). But if you got a White screen, that means backlights are working. So Im stumped too lol. Check T-con board.

[@jeffcaidler572]

@@bigdog8882 Great thanks ,ok ill give it a try ,has for no sound would that be on tcon as well on somemodels attached to the display

[@bigdog8882]

@@jeffcaidler572 No , the mainboard produces the sound.

[@jeffcaidler572]

@@bigdog8882 Ok ,makes sense , i guess illtry the mainboard

[@bigdog8882]

@@jeffcaidler572 For sound problems always check the speakers first b4 you change Main board. Put meter is resistance mode and make sure the ohms match whats written on the speakers, and not reading open.

[@saarike]

Great repair and tips!!! My humble thanks.

[@bigdog8882]

You bet

[@MrA4awesome]

Hello, can the SR5150 be replaced with a different type of diode? I don't have those easily available to me locally.. Thanks

[@toshisate8121]

Great troubleshooting... Bear down

[@spenceredwards2664]

I have a Samsung un55nu7100. No stand by light. Won’t come on or do anything. I’ve replaced power board and main board and still nothing. Led voltage are 3-5v when they should be 12.8. Is the back light bad?

[@AK2I47]

How can you tell if a mosfet driver IC is dead? It is easy to determine that when the mosfet is driven by a singe tiny smd transistor but gets difficult when an IC is used.

[@bigdog8882]

There are a few things to check like, Vcc, output signals, gate drive, shorts on Vcc line, start-up, etc. All of that is covered in the course. Good question tho.

[@AK2I47]

@@bigdog8882 I know output signals is a major factor but I forgot to mention that I do not own an oscilloscope. I was wondering if my meter would still read the frequency?

[@bigdog8882]

@@AK2I47 Maybe, but the only problem; depending on the meter is, it may not be accurate and you want to actually SEE the signal and duty cycle.

[@AK2I47]

@@bigdog8882 Once I get KHz that should be good

[@johnm4962]

thank you

[@hakikosaber1645]

Good job .thanks .

[@bigdog8882]

Welcome

[@SorenCarlsson-qr9gy]

I fixed my backlight on my Sharp 70 inch tv and it has worked for a while but now the left side of the tv i black the right works fine what else can be wrong?

[@bigdog8882]

probably backlights. U have to check the return line on that side thats dark.

[@SorenCarlsson-qr9gy]

@@bigdog8882 ok every ledlightlamp is shining maybe it s the contector on the panel thats burned or the panel is broken

[@SorenCarlsson-qr9gy]

@@bigdog8882 can a panel be half broken? i cant see any crack in the left panel side .

[@SorenCarlsson-qr9gy]

@@bigdog8882 after a couple of hours tv running. tv left panel side show green vertikal lines so i guess some connection is bad

[@SorenCarlsson-qr9gy]

@@bigdog8882 i made a Hard reset and took the cables behind out and put them back again and the start cooling the tv with a fan so now it works fine

[@brianjames6890]

Another great upload. Big Dog. 8882. Please can you send me any information on how I can join your tutoring. Many thanks in anticipation regards, Brian 👍👏🏴󠁧󠁢󠁷󠁬󠁳󠁿👍👏🏴󠁧󠁢󠁷󠁬󠁳󠁿

[@bigdog8882]

Any time Brian! bigdogtvrepaircourse.mykajabi.com/

[@yaghiyahbrenner8902]

please use flux when desoldering it helps with not destroying pcb traces and pads.

[@LukeHoneyball]

What a guy!

[@AbidHussain-qh2ms]

JVC, LT-32A100 switching on tv after 15 to 20 mnts the brightness increases and the screen goes black, the indicator light and sound good, backlight stayed with very low power. When powering on from the remote, the picture comes on but then 15 mnts later goes away This happens again and again. Need your help, plz give some tips to guess which board may be faulty.

[@vernonbosshard9317]

Why not ground pin 4?

[@bigdog8882]

I dont think that would work cause the opto would still be in the circuit. Then that would be like removing the 2 opto pins and shorting the 2 traces together instead of using a diode.

[@bigdog8882]

Good question.

[@vernonbosshard9317]

@@bigdog8882 I assume when that opto transistor turns on Vce is near zero? On the other side they have a resistor across the LED, .5 volts seems reasonable. This is why I need schematics for TVS, I can't visualize it in my mind, like a deer in headlights. If you put it on paper I get it all day. I like bread boarding stuff like this, measure it and understand it, but with paper I'm lost. I'm getting fed up with Ebay buying parts, they advertise OEM quality parts but that's not what you get. Its full of fakes and knockoffs. We need radio shack again!!

[@bigdog8882]

@@vernonbosshard9317 I think radio shack was my favorite store. So sad they closed down. They were all over Chicago like liquor stores. lol.

[@electronicartis]

bigdog good details in video. keep it up.

[@frankhughes9580]

I hear you but the video part of your show is blacked out 🤔

[@alcobia09]

I just saw and heard the video... it worked for me.

[@DADEMANA]

nice

[@bigdog8882]

Thanks

[@kamalbuddhika6159]

👏👏👏

[@Falco361]

hoping someone can point me in the right direction with these readings i have on a 70 vizeo i would like to keep please 1.gnd-0 15.T-con_on-0 2.gnd-0 14.12vs-167.5 3.24v1-24.6 13.12v1-0.4 4.24v1-24.6 12.nc-6.4 5.24v1-24.6 11.nc-0.55 6.24v1-24.6 10.nc-0 7.24v1-24.6 9.+12v1-12.6 8.24v1-24.6 8.+12v1-12.6 9.gnd-0 7.gnd-0 10.gnd-0 6.gnd-0 11.gnd-0 5.gnd-0 12.nc-7.5 4.12vs au-12.75 13.nc-0.1 3.ps_on-2.3 14gnd-0 2.ac_det-3.8 1.nc-80.1

[@edwardanthony7283]

Depends on the price of a new board but I did not like Sony for televisions.

[@davidsonneidert5523]

*Promosm*