KDL-46S4100 - Intermittent Black Screen & No Sound

[hdguy]

I picked up a Sony KDL-46S4100; original owner was selling because it would intermittently shut off. It had been sitting in her basement unplugged for about 3 months until today.

When I got it home, I watched TV for about 90 minutes with no issues, until it happened to me. During that time, the picture was crystal clear.

Now, it may turn on every 7-8 times of turning on, and it doesn't stay on for long. The power light is green, and stays on regardless of whether or not the TV displays a picture. The power light does not flash (any codes). I hear the 'click' of the relay when I turn it on (the sound doesn't change, regardless of if it works or not).

I watched a YouTube video, "SONY KLDL 46 S4100 BLACK SREEN REPAIR HELP", and his TV is doing the same as mine - right down 5 pin connector (4 wires) lights up the backlight when removed.

I'm thinking of replacing the "Sony 1-857-092-41 Main A Board for KDL-46S4100", but I wanted to see if anyone had any ideas first. Additionally, I am not afraid of soldering components, but unfortunately I'm not very well versed in troubleshooting at that level.

Thoughts?

[dskall]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Your losing backlights? You have picture on screen when looking with flashlight?

[budm]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Since you are able to get the backlilghts to come on by disconnecting the backlights control connector but you still do not see any images on the screen which means you have more than one problem with the main board (or T-CON), you do not have the BL-ON, and also no images on the screen, you do have PS-ON.
I would check to see if you do have 12VDC on the SMD fuse on the T-CON board.
May be it needs firmware reloaded. There are many threads about this model.

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Sorry for the long delay - great summer with the kids.

Original Problem:
TV turns on, and suddenly goes blank, no sound. No indication of it being the backlight failing (did the flashlight test). Power light stays on and is green.

I purchased a "Sony 46 KDL-46S4100 1-857-092-21 55.71H01.411G 55.71H01.411 V.2 Main Video Board" off of eBay. It worked for almost a week straight, and then failed with the exact same symptoms. I put my original board back in, and suddenly IT worked.

Another week went by, and my old board failed again, although this time, it is more intermittent, although I've further isolated the symptom:

• If I am watching TV OTA, it will go out for 30 sec to 5 min, and then come back on; it might do that (3) or so times in a 2 hour period.
• If I use an HDMI source, the TV fails almost immediately.

Thoughts?
(as always, thank you for the guidance from the great people on this site!)

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

**Update** - I applied firmware update V1.115 and now it is worse. Before when it would "freeze" (no sound, no pic) I could press the channel +/- a few times and at least watch OTA TV programming. Now I seem to be stuck in one of the HDMI inputs, with no way out.

Any thoughts?
I'm about to give up on this TV, so any help would be greatly appreciated.

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

This TV has been sitting around waiting to be fixed or junked; it's already difficult for me to just give up on it... Now to find out it would cost ~$25+ to dispose of it - no way!

As I mentioned in the previous post, I purchased the Main Board off of eBay and the exact same symptoms occurred - it worked for a week or so, then shut off - after trying multiple times, it will come back on, but only stay on for a few minutes.

It is screaming BADCAPS somewhere, right? Since I replaced the Main Board with a used one off of eBay (yes, I am assuming the 2nd Main Board was not suffering from the same issue), I think I am going to purchase a replacement power supply off of eBay/ShopJimmy next.

Any other thoughts?
Is there some other board I should focus on first?

As always, thanks for your input!

[cartgen]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Service Manual for this model:
https://servlib.com/sony/tv/kdl-40s4...l-46s4100.html

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

I've looked at the book, but unfortunately I am not technical enough to read the schematics and know what to probe (not to mention the problem is intermittent).

I'm usually very good about finding "the thing" that fixes these kind of issues by scouring the BADCAPS.net forum, as well as asking Senor Google. Other than a fairly common them about lines on the screen & the TCON board (I'm not having this issue), no one seems to have gotten to the bottom of this issue.

Any ideas on the next board or parts to replace?

[augiedoggy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Ive repaired a few of these already...I have this set thats waiting to be sold now that I had the t con repaired (no luck just changing the as15 chip myself) (I actually have a 40 s2010 model with a bad inverter sitting in my garage now along with about 30 other flat screens all waiting for a home before repairing what I know is wrong with them.. Sadly enough they arent really worth much of anything as im finding many of the similiar sets im picking up at the recycling yard work fine and were tossed because in the owners eyes they were "old" and replaced with smart or 4k led sets so the fools can watch upconverted 480p or 540p in worse quality upscaled to 38xx lines of resolution until the leds burn out in two or three years if they are lucky.

[augiedoggy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Sorry for the long delay - great summer with the kids.

Original Problem:
TV turns on, and suddenly goes blank, no sound. No indication of it being the backlight failing (did the flashlight test). Power light stays on and is green.

I purchased a "Sony 46 KDL-46S4100 1-857-092-21 55.71H01.411G 55.71H01.411 V.2 Main Video Board" off of eBay. It worked for almost a week straight, and then failed with the exact same symptoms. I put my original board back in, and suddenly IT worked.

Another week went by, and my old board failed again, although this time, it is more intermittent, although I've further isolated the symptom:

• If I am watching TV OTA, it will go out for 30 sec to 5 min, and then come back on; it might do that (3) or so times in a 2 hour period.
• If I use an HDMI source, the TV fails almost immediately.

Thoughts?
(as always, thank you for the guidance from the great people on this site!)

I'm going to say your issue has to be tcon or main board related if the content really makes a difference here.

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Thanks augiedoggy for the feedback. I already replaced the Main Board and I experienced the same issue after about a week of usage.

I just purchased a replacement power supply board off of eBay (they have an acceptable return policy) I'll let you know if that helps.

Thanks again for the feedback and keeping the post active - Tim

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

The used power supply from eBay did not solve the problem.

The TV ran for about 30 hours, and then today exhibited the same symptions; hear a click of the power going on in the TV (after pressing the remote 'on' button), but the screen won't turn on. Same as before.

I guess based on the feedback here, I should attempt to replace the TCon board? Any other thoughts? Is there some troubleshooting I should do first, to help narrow down the issue. As a reminder, I already swapped the Main Board, but the problem existed there too - although I'm very curious if the eBay auction board just had the same problem as mine... works for 30hrs and then dies. Again, reminder, this TV will work for about 2 days if I unplug it and don't use it for a month.

Thanks for the ideas and feedback so far!
Tim

[budm]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

So did you take any Voltage readings when the TV was working for 30 Hours to record what it has and what it does not have now?

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

No I did not take any readings; I'm not sure where to start.

I've read a lot of different posts on this forum about this TV. It doesn't seem like anyone has ever got it working - at least not a fix that anyone has posted.
By the way, I disconnected CN303 and my backlights lit up, with a black screen (I mention the black screen, because I've read about color patterns, red screens, and blue screens)

[budm]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Well, when you say intermittent black screen, does it mean you lose the backlights or you still have the backlights but no pictures?
If you do have backlights but no image on the screen then you should at least take the DC Voltage reading on the T-CON fuse to see if you still have 12V on both ends of the fuse or not with ref. to the chassis GND.

[hdguy]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Well, when you say intermittent black screen, does it mean you lose the backlights or you still have the backlights but no pictures?

When I say intermittent, I mean the TV has worked for days, or even weeks, but then will not power on. Once "out", it stays out, until I give up on it for a few weeks/months. That's why I say intermittent. At this point it is not working - Upon power-up (with remote), I hear a click and the power light goes on. The backlights do not turn on (even after waiting 10 sec), which is normal when it is working properly.

I saw several posts about disconnecting CN303 - when I do that, the backlights turn on, with a black screen.

Thoughts?

[nomoresonys]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Mine wouldnt do anything, when I unplugged the mainboard from powersupply board, the backlights would turn on with a red green blue repeated pattern, tried many boards, finally figured out it needed the firmware put back on, it got borked in a storm I think, anyway after the replace, it fired right up, solved that issue, then had the problem of turning off after 30 minutes like yours, only cure I found for that was leave the back off.

[nomoresonys]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

I see you did do the firmware, your symptoms are different than mine, guess it's possible the firmware didn't go on right??? I think I remember someone having to try the firmware a few times before it took.

[nomoresonys]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

There's a procedure to applying the firmware, I think it's in one of my posts from 2014, if I recall, it's put in usb drive turn on tv wait for 2 yellow lights or blinks then turn off tv and remove, will try to find the thread.

[nomoresonys]

Re: KDL-46S4100 - Intermittent Black Screen & No Sound

Ok just reread my thread, was having your same symptoms, what I did was take the back off and let it run, no more problems, makes me think it's a overheating issue, in my situation I just mounted it and left the back off, no small children or animals, an alternative would be drill a bunch of holes in the back, while off the tv of course, for better ventilation. it's been going strong now for like 3 years.