Samsung PN60E550 Cannot Confirm Y-Main Failure

[Truncatedhose]

Hi guys (and gals?)

I'm working on another big Samsung Plasma (I would post pictures, but this is such a common model and the pictures at the Fast Track guide are linked below) and I'm having the issue described in this AVS forum thread:

http://www.avsforum.com/forum/167-pl...s-look-ok.html

---which is sound but no picture whatsoever. There is no glow or brief flash or anything. Also, if you read through the short thread at AVS forum, you will see towards the bottom there are guys saying that sometimes the problem was/is intermittent. That is also the case with this TV I'm working on, although, it got to the point over several months where now it never has a picture. I'm tempted to just replace the Y-Main, but I don't really feel like I've confirmed it's failure; none of the fets are shorted on it or the X-Main.

My findings: The VS, VA come up to full voltage when the TV is plugged in, but immediately start to drop. Anyway, I thought this might another of the models that get bad connections on the PSU, so I resoldered some suspicious looking connections and the common bad areas, but no help. The logic board had a blinking led once every 5 seconds, although later, when I pulled the Y-Main to inspect and test it's fets, then put it back in---now the logic board seems to have a solid led for 5 seconds, but then blinks off for 1 second....? I didn't mess anything up in the pull and reinstall...I've checked and checked. I don't know why the logic board led would change like that.

I've tried following the fast track troubleshooting guide here:



----but, I'm not sure exactly how to apply the steps there to this problem and I'm confused about how to unplug the Y-Main or X-Main to pinpoint what is causing the VS, VA drop without causing the set to go into shutdown just by unplugging them.

Any help?

Thanks!

[fberni]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

I have the same problem and found the ybuffer board to be the problem

[tom66]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Check Vscan, can be intermittent controller IC (according to one user on this forum)

[drussell]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Check Vscan, can be intermittent controller IC (according to one user on this forum)

Yes, please have a look at:

https://www.badcaps.net/forum/showthread.php?t=43075

I've had several queries about the status of this project. I'm still waiting on replacement ICs to do further testing but both of the TVs in this series that I was working on work fine with the temporary hack of the voltage-divider pre-charge for the -Vscan PWM controller IC.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

I have the same problem and found the ybuffer board to be the problem

Was it the upper or lower buffer and how did you confirm this?

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Check Vscan, can be intermittent controller IC (according to one user on this forum)

Tom, the pics showing the VSC and VE test points on the Fast Track guide don't seem to match my board, but I see that they aren't matching the large pic on the guide, too, so I dunno. Anyway, I'm not sure I'm probing the right test point, but I seem to get 0 volts for the VSC on the Y-Main and 2 volts for VE on X-Main. Also of note, I don't hear any click when I plug the TV in, but the VS and VA come up to full, but immediately are dropping at about 3 volts every half second, again with no clicks of any kind. Whn I press the power button, nothing happens, but I think it's trying to power on as soon as AC is supplied. Also, remember, I do have audio, which is baffling because I never hear a relay click, but I guess that's not part of that process.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Yes, please have a look at:

https://www.badcaps.net/forum/showthread.php?t=43075

I've had several queries about the status of this project. I'm still waiting on replacement ICs to do further testing but both of the TVs in this series that I was working on work fine with the temporary hack of the voltage-divider pre-charge for the -Vscan PWM controller IC.

Thank you for this link. I did read most of it, but I'm wondering if you might be able to give me some steps I might start with to see if my problem is the same.

[drussell]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Tom, the pics showing the VSC and VE test points on the Fast Track guide don't seem to match my board, but I see that they aren't matching the large pic on the guide, too, so I dunno. Anyway, I'm not sure I'm probing the right test point, but I seem to get 0 volts for the VSC on the Y-Main and 2 volts for VE on X-Main.

The pictures in the fast-track troubleshooting guide are incorrect. They must be pictures of a different board set for a different model or something. The Ve and -Vscan test points are fairly well labelled, though. The Ve testpoint is to the right of the [VE] label with the box around it on the X-Main board, just past the lower 150uF, 250v capacitor but to the left of the film capacitor. The -Vscan testpoint is just below and to the left of the -Vscan adjustment potentiometer on the Y-Main board.

The lack of -Vscan causes the logic board to not bring up the Ve supply and go into protection lock-out removing the VS_ON signal and disabling the high voltages from the power supply. The PS_ON signal stays enabled (low) so the low voltages remain on, however, so the TV is actually on and you get sound.

Also of note, I don't hear any click when I plug the TV in, but the VS and VA come up to full, but immediately are dropping at about 3 volts every half second, again with no clicks of any kind.

There are no relays in these models so there will be no audible clicks.

Whn I press the power button, nothing happens, but I think it's trying to power on as soon as AC is supplied. Also, remember, I do have audio, which is baffling because I never hear a relay click, but I guess that's not part of that process.

If the TV is on when power is removed it will return to a power-on state when power is re-applied.

...but I'm wondering if you might be able to give me some steps I might start with to see if my problem is the same.

Try some freeze spray on the Infineon ICE3BR0665J at U5014 right below the transformer for the -Vscan on the Y-Main board. That made the ones here fire right up. (Post #26, etc. in that thread) You can also try the voltage divider trick from posts #31 and #33.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Drussell, thank you so much for all your help! You put a lot of time in and I appreciate it!

Yes, I assumed those were the test points, but wanted to make sure.

So the VE hovers around 5v or 6v for a couple moments and then raises to 11v. The VSC almost reaches -1v, but slowly raises to 0v.

The lack of relays would explain the no clicks! I never realized relays would not even be in the this model.

Okay, I froze U5014 and bingo! Plugged in the set and it came on with good picture. I'm letting it run now. So, do you think the voltage divider thing would not be a good/permanent fix?

Edit: Whoops, looks like I had over spray and hit C5162 and THAT is what makes it come on. (I admittedly did see my freeze blast hit the cap next to chip the first time I did it). I've repeated the test several times now (warming the area back up between attempts) and freezing U5014 doesn't do it; it's freezing C5162 that does it (I was very careful in how I sprayed).

I read further on in that thread and Magicsmoke seems to have had the same thing happen to him. What should I do? Did he say that changing the cap only would solve it? I don't know that there was ever a clear final post. And it's really okay to put a polarized electrolytic 10ufd capacitor in there in place of the little blue cap? It wouldn't matter which direction to put the cap? And I would remove the blue cap, right? Let me know what you think I should try. Also, should I replace the cap INSTEAD of making the voltage divider and installing it, or IN ADDITION to doing that? Or do you think just trying the voltage divider alone? Sorry for so many questions!

[drussell]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Okay, I froze U5014 and bingo! Plugged in the set and it came on with good picture. I'm letting it run now. So, do you think the voltage divider thing would not be a good/permanent fix?

Edit: Whoops, looks like I had over spray and hit C5162 and THAT is what makes it come on. (I admittedly did see my freeze blast hit the cap next to chip the first time I did it). I've repeated the test several times now (warming the area back up between attempts) and freezing U5014 doesn't do it; it's freezing C5162 that does it (I was very careful in how I sprayed).

I read further on in that thread and Magicsmoke seems to have had the same thing happen to him. What should I do? Did he say that changing the cap only would solve it? I don't know that there was ever a clear final post. And it's really okay to put a polarized electrolytic 10ufd capacitor in there in place of the little blue cap? It wouldn't matter which direction to put the cap? And I would remove the blue cap, right? Let me know what you think I should try. Also, should I replace the cap INSTEAD of making the voltage divider and installing it, or IN ADDITION to doing that? Or do you think just trying the voltage divider alone? Sorry for so many questions!

If it seems to be the capacitor then replace it and see if it works. I don't see why an electrolytic can't replace that multi-layer ceramic capacitor but you will have to observe polarity, be sure the negative side goes to the left when you're looking at the top of the board as installed in the TV. This is ground so it is easy to double check with your multimeter to be sure you get it in the correct way around.... Just be sure to get the - side to ground if you use a polarized capacitor. It should really be at least 35 volts, 50v would be a good choice.

I tried swapping capacitors on one of the ones here and it didn't help (at one point I thought it was the capacitor also), whereas freezing the chip itself seemed to work on these ones here. Go figure. Perhaps the capacitor I tried is too leaky as well, I haven't gone back and tried messing with it again yet. I'm not sure why that circuit seems so flakey but essentially whatever you do that makes it actually work should be just fine.

As for the voltage divider, don't do it if changing the cap or IC or whatever works. It really SHOULDN'T be a horrible thing to charge it up that way and you theoretically should be able to do that without any ill effects in the long run but it is a bit of a bodge so better to actually repair the circuit if possible rather than just hacking around it, IMHO.

I think MagicSmoke's latest info was essentially that the one that worked correctly was the board that he changed BOTH the IC and the capacitor. His set seemed to be shutting down, though, after running for some length of time whereas the ones here both stay on just fine once they start so it is entirely possible that they are two different variations of the same basic problem. It is possible that changing the capacitor to one with no leakage will band-aid a weak pre-charge supply in the chip but there still may well be a problem with the chip. It might be prudent to change both to prevent future problems but if it is your own TV you can decide, you can always open it back up again later.

Once I actually get some of the ICs I will try the various combinations and report back whatever worked here but that doesn't mean it will be the same in each case on each TV but at least you've isolated it to that same circuit as well. This circuit certainly looks like a common failure point, regardless....

Let us know what you end up finding as if you seem to find the capacitor involved also I think I will replace the capacitors in these ones also to try to ensure reliability.

[drussell]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Oh, and yes, you will want to remove the original blue capacitor. Adding capacitance to it isn't going to solve the problem. The problem must be that the blue one is leaky so is bleeding off some of the charge current trying to be supplied by the PWM controller IC's startup circuit and it is not making it up to normal voltage to turn on.

[drussell]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Humourously enough, just as I was about to walk out the door, about 15 minutes after I posted that last message the postman delivered the ICs. I'm pretty sure I supposedly ordered them from China but they came from Singapore. Go figure! About what I expect from the surplus seller guys but whatever, they're here.

Anyway, I'll see if I can manage to find some time soon to delve into this a bit more closely now that I have some of the chippies...

[MagicSmoke]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

To clarify... I changed the film cap @ C5162 to a 10uf 50v electrolytic and changed the Infineon ICE3BR0665J chip @ U5014 on both of the Y mains I have.

Both work perfectly now. I let each run for over 5 hrs with power cycles every 40 min or so. My panel turned out to be bad but I have working boards.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Humourously enough, just as I was about to walk out the door, about 15 minutes after I posted that last message the postman delivered the ICs. I'm pretty sure I supposedly ordered them from China but they came from Singapore. Go figure! About what I expect from the surplus seller guys but whatever, they're here.

Anyway, I'll see if I can manage to find some time soon to delve into this a bit more closely now that I have some of the chippies...

Thanks again for your help! It sounds like I should order that chip and replace it with the capacitor for reliability. I guess I'll have to wait for the chip then. I'd hate to only do the cap and later have it start having the same symptoms again.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Also, are you sure it wouldn't be better to use the same type of cap or is there a reason you guys are using an electrolytic other than immediate availability?

[drussell]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Also, are you sure it wouldn't be better to use the same type of cap or is there a reason you guys are using an electrolytic other than immediate availability?

I'm quite certain it is not any type of plastic film capacitor, it's too small, and doesn't look like a tantalum or anything fancy. (Well, and can't be tantalum since these are non-polarized.) I'm pretty sure it is actually some kind of multilayer ceramic capacitor. There are over 30 of those exact same capacitors in the TV and I would think they get super cheap ones. It shouldn't really be getting worked hard in any way in this circuit application so I don't see any reason why an electrolytic wouldn't work just fine in there but I suppose you could use some exotic type for reliability if you wanted.

Quality multilayer ceramic caps from somewhere like digikey cost more than an electrolytic but I can't see any reason why it would perform better.

Does anyone have any ideas why they would have specified that cap other than theoretically being more reliable and perhaps cheaper than an electrolytic? In this case it certainly doesn't seem to have been reliable but I am assuming that is due mostly to component "cheapness". Ceramic capacitors don't usually fail but I'm guessing these are of dirt cheap manufacture. It still seems crazy to me that such a tiny capacitor is actually 10uF. That kind of thing didn't even exist until recently.

There don't seem to be any <25uf electrolytics in the whole TV, they use little blue (what I think are ceramics ) everywhere in a couple different values throughout the TV... There are something like 60 of them in there not counting the similar looking but different safety and high voltage isolation caps between primary/secondary sides of the PSU and the larger blue dipped ones on the buffer boards which are definitely film (small value and say MPE on them).

These little blue guys just say 106 on them, no indication as to chemistry/construction.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

I'm quite certain it is not any type of plastic film capacitor, it's too small, and doesn't look like a tantalum or anything fancy. (Well, and can't be tantalum since these are non-polarized.) I'm pretty sure it is actually some kind of multilayer ceramic capacitor. There are over 30 of those exact same capacitors in the TV and I would think they get super cheap ones. It shouldn't really be getting worked hard in any way in this circuit application so I don't see any reason why an electrolytic wouldn't work just fine in there but I suppose you could use some exotic type for reliability if you wanted.

Quality multilayer ceramic caps from somewhere like digikey cost more than an electrolytic but I can't see any reason why it would perform better.

Does anyone have any ideas why they would have specified that cap other than theoretically being more reliable and perhaps cheaper than an electrolytic? In this case it certainly doesn't seem to have been reliable but I am assuming that is due mostly to component "cheapness". Ceramic capacitors don't usually fail but I'm guessing these are of dirt cheap manufacture. It still seems crazy to me that such a tiny capacitor is actually 10uF. That kind of thing didn't even exist until recently.

There don't seem to be any <25uf electrolytics in the whole TV, they use little blue (what I think are ceramics ) everywhere in a couple different values throughout the TV... There are something like 60 of them in there not counting the similar looking but different safety and high voltage isolation caps between primary/secondary sides of the PSU and the larger blue dipped ones on the buffer boards which are definitely film (small value and say MPE on them).

These little blue guys just say 106 on them, no indication as to chemistry/construction.

Yes, I had the same speculation after some more investigation into the cap. I will go ahead and put the electrolytic in and a new chip (when it arrives) and will report back.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

Okay, this is crazy. I got the new chip (from the ebay source you provided) and installed it along with a 10ufd 100v electrolytic; I made sure to put it in with negative lead to ground. Tried the TV and same exact symptom as before. I tried it a few more times and waited a bit just to be sure; still nothing. Then I freeze-sprayed the new chip and it immediately came on and worked. What in the world? I'm thinking that freezing this chip doesn't mean it's bad, but just that lowering it's temperature changes something and is somehow just what the circuit needs to function. I don't know where the failure would be though. Especially since I was finding before that freezing the cap would cause it to come on, but also freezing the original chip would, too. I haven't bothered with freezing the replacement cap now.

Ugghhh....

Need some help here. I'm think about just giving up and making the voltage divider. What do you think?

[MagicSmoke]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

100v may be to much. I used a 50v cause I did not have a lower voltage 10uf.

The highest volts I recorded on the circuit was less than 20v so a 25v cap might be better?

I changed both chip and cap on 2 separate boards and both were tested and worked fine.

[Truncatedhose]

Re: Samsung PN60E550 Cannot Confirm Y-Main Failure

100v may be to much. I used a 50v cause I did not have a lower voltage 10uf.

The highest volts I recorded on the circuit was less than 20v so a 25v cap might be better?

I changed both chip and cap on 2 separate boards and both were tested and worked fine.

Thanks for the reply. I thought the voltage on an electrolytic doesn't matter as long as it's higher than what's called for? Does this rule not apply in this case since we are changing the type of capacitor from what it was originally? Also, did you read where I can freeze the new chip and the TV will come on?