Samsung HP-T4264 ~ Clicking and no picture or sound

[kca]

Hello all ~

I picked up a Samsung 42" plasma the other day and was hoping it was a simple fix via capacitor replacement. When I first opened it up, two 1000uf 25v caps were clearly bulging and leaking.

Replaced them, and the set continued to click (relay in the PSU) and produce no picture or sound.

Removing the connector between the PSU and the Main Board causes the clicking to cease. No other connector removal has any effect on the clicking.

Does this mean that the Main Board is defective, or is there a possibility that the problem still rests in the PSU itself?

Some other observations I have already made:

1) The two fuses on the PSU along with the 1 on the YSUS and the 1 on the XSUS are all in working order.

2) No Vs readings are present. And, I only get a 0.6 reading on one of the Va pins.

3) One key piece of evidence seems to be that the PS-ON readings on two of the connectors both fluctuate between 3.2 down to 0.2 and then back up to 3.2 over and over again in sequential alignment with the set clicking on and off as described above. This circular loop takes about 7 seconds or so to complete before it repeats itself indefinitely.

4) I do get 5.3v readings on some of the Standby pins, but not on all of them.


I can and will post pictures tomorrow, but was wondering if anyone out there has seen these same conditions in a Samsung plasma and can offer some feedback this evening. I still have the set open and am working on it right now.


I am going to try here to describe the connectors and all of the voltage readings I just took:

There are three connectors running up and down the right-hand side of the PSU. From top to bottom, there is a six pin, a five pin, and a three pin respectively. Here are the readings off of those:

Vs = 0.0
Vs = 0.0
RTN = 0.0 {This connector feeds out to the YSUS}
RTN = 0.0
RTN = 0.0
Ve = 1.1 (not sure if that is an e, but it looks to be one)


Vs = 0.0
Vs = 0.0
RTN = 0.0 {This connector feeds out to the XSUS}
RTN = 0.0
Ve = 1.1


5.3v = 1.1
RTN = 0.0
Va = 0.6


Then, there are three connectors that run along the bottom of the PSU. They read, from left to right:

This first connector actually has no plastic connector on it; instead it is just an "open port" consisting of 8 touchpoints. I included it here because the Standby voltages are all reading correctly on the first four touchpoints.

Standby = 5.3
Standby = 5.3
Standby = 5.3
Standby - 5.3
RTN = 0.0
RTN = 0.0
RTN = 0.0
RTN = 0.0


This next connector has double rows, 12 pins on each side .....

0.0 = N.C / PS-ON = 3.2 down to 0.2 and back up to 3.2 (as I described above)
0.0 = RTN / Standby = 5.3
0.0 = RTN / RTN = 0.0
1.1 = AMP / AMP = 1.1
0.0 = RTN / RTN = 0.0
0.0 = RTN / RTN = 0.0
1.0 = 5.3v / 5.3v = 1.0
1.0 = 5.3v / 5.3v = 1.0
0.0 = RTN / RTN = 0.0
0.0 = RTN / 12v = 1.0
1.0 = 12v / 12v = 1.0
0.0 = N.C / FAN_ON = 0.0


The last connector across the bottom of the PSU (in the bottom right-hand corner of the PSU) has the following readings:

Standby = 5.5
Vs_On = 0.0
N.C = 0.0
PS-ON = 3.2 down to 0.2 and back up to 3.2 (in the same repeated, indefinite sequence as I have described above
RTN = 0.0
5.3v = 1.1
RTN = 0.0
RTN = 0.0
5.3v = 1.1
5.3v = 1.1


So, that's it. Kind of a mixed bag of correct and incorrect voltages. Hoping there are folks out there who have seen the same and/or who can help me track down the root cause of the problem.

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Here is a photo I've marked up showing the six connectors I described in the post above (in red), along with the two capacitors I already replaced (in blue) and the two fuses which have always read as good (in pink).

Please note that this photo is NOT my particular PSU. Rather, it is a generic one I took off the internet.

I will take pics of my own tomorrow when I have a bit more time.



~ kca

[dick_barton]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

With the set off have you checked to see if you have a short circuit on any of the supply lines. Va, Ve, etc

[tvtimmy]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

There are 2 470uf caps that have to be changed too. They wont look bad but I have had 4 of these tvs with this problem. You should replace the rest of them also.

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Haven't checked for shorts on the Va, Ve, Vs lines yet, dick_barton, but I will do so today.


tvtimmy ~ I was wondering if those large caps might be the source of the lingering problem. You are referring to the two that rest side by side, I assume, near the top middle of the board? What about the larger one that is in the upper right corner? Did you replace that one as well?

I don't really want to replace every cap on the PSU. I have done that twice in the last six months on two other tv's, to no avail. I am hoping to be more pinpointed in the analysis and assessment based on the readings noted above.

Was also thinking about reflowing the board today in the oven. Did this once before with success and have heard that cold solder joints can be a big problem with this particular PSU. I visually inspected the back side yesterday and nothing seemed to be out of order, but I know that these cracks / openings can be very hard to detect at times.

One other note: When I tested the PS_On pin on the 24-pin connector (goes from PSU to Main Board) with the connector REMOVED, it read a steady 4.4. Only with the connector put back in (and therefore connected to the Main Board), did it read the fluctuating 3.2 down to 0.2 and back up to 3.2 over and over again.

What does that mean?


Same readings from above, with the amended note in green:


This next connector has double rows, 12 pins on each side .....

0.0 = N.C / PS-ON = 3.2 down to 0.2 and back up to 3.2 (as I described above) Reads a steady 4.4 when the connector is removed
0.0 = RTN / Standby = 5.3
0.0 = RTN / RTN = 0.0
1.1 = AMP / AMP = 1.1
0.0 = RTN / RTN = 0.0
0.0 = RTN / RTN = 0.0
1.0 = 5.3v / 5.3v = 1.0
1.0 = 5.3v / 5.3v = 1.0
0.0 = RTN / RTN = 0.0
0.0 = RTN / 12v = 1.0
1.0 = 12v / 12v = 1.0
0.0 = N.C / FAN_ON = 0.0

[tvtimmy]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Replace the two of them to the left of the ones you changed. Then on the right side of the heatsink, change the 5 green ones and the two brown ones. That usually fixes this model. Use good low esr caps.

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Hello all ~

Got busy and had to put this aside, but now I'm back at it.

First question is for tvtimmy. Can you please look at the picture I've attached and tell me if the caps I have outlined in YELLOW are the same, exact ones you described in your post above back on October 3rd?

By the way, and importantly, just yesterday (10/25) I replaced the two 220uf 450v caps that sit in the upper middle of the board, right next to one another. The result was that there was no change at all. Same clicking on the same cycle. Still no picture, still no sound, and still no standby indicator lights on the front of the tv. Nothing changed for the better or for the worse..

Please see the 2nd image below. The two 220uf 450v caps in question are marked in green.

Note: I replaced them with 270uf 450v instead of 220uf because the store I go to only had the 270uf's. If that is a big problem, please let me know. I know it is slightly out of the 20% +/- range, but the folks at the store thought it would be okay to use these in this instance. If they need to be an exact match, I can go online and get the 220uf 450v caps if necessary.

I did not yet replace the large 680uf 250v cap in the upper right-hand corner of the board because no one here on Badcaps was really pointing to that as a likely reason for this particular "clicking / cycling" type of fault.

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

I am also including a picture here of my actual board and the voltages I am getting. These all match what I wrote up above earlier this month. I just thought the visual might help someone out there to lend more advice.

The "E" connector has the following readings (I just didn't have enough room in the photo to mark it up, as it has 24 pins ~ 2 rows of 12):

0.0 = N.C / PS-ON = 3.2 down to 0.2 and back up to 3.2 (as I described above) Reads a steady 4.4 when the connector is removed
0.0 = RTN / Standby = 5.3
0.0 = RTN / RTN = 0.0
1.1 = AMP / AMP = 1.1
0.0 = RTN / RTN = 0.0
0.0 = RTN / RTN = 0.0
1.0 = 5.3v / 5.3v = 1.0
1.0 = 5.3v / 5.3v = 1.0
0.0 = RTN / RTN = 0.0
0.0 = RTN / 12v = 1.0
1.0 = 12v / 12v = 1.0
0.0 = N.C / FAN_ON = 0.0

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

What I am trying to figure out, first and foremost, is if all of these readings / information tells anyone out there if the PSU is at fault or if the MAIN BOARD is actually the culprit.

I can get a new MAIN BOARD off of Ebay now for only $16, but who knows if that is defective or not?

Does the fact that I am getting correct Standby voltages on the "D" connector, the "E" connector, AND on all 4 pins of the "open connector" (see my first post on this thread above from October 2nd) indicate to anyone that it might really be the MAIN BOARD that is at fault?

I like and appreciate tvtimmy's advice re: changing out all of those caps because he has had such overwhelming success in doing so (I found your post, tvtimmy, on another thread where it said you had successfully fixed 8 of these now with this method of cap replacement), but I also want to rule my MAIN BOARD in or out of consideration when it comes to ordering parts.

Is there a way I can test to see if the MAIN BOARD is faulty or not?


Any thoughts or further suggestions for testing would be appreciated.

~ kca

[Andrew F. Ali]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Is there a jack that have the label VS-ON?

[dick_barton]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Some information suggesting poor solder joints
https://www.badcaps.net/forum/showthread.php?t=35286


Is this the power supply that has problems with the capacitor going short circuit on one or other of the two small daughter boards?

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Andrew F. Ali ~
Yes, the Vs_On is located on the 2nd pin of the “D” connector in the photo I posted earlier this morning.

It reads 0.0

[Andrew F. Ali]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

OK. Since you can identify the Std-By 5V, VS-ON and PS-ON.
Disconnect ALL wires from the PSU to the other boards
Take a pair of 120V light bulbs and connect them in series, leaving the end wires just long enough and connect to the VS connector on the PSU.
Connect a short wire from Std-By to PS-ON.
Connect another short wire from Std-By to VS-ON.
Plug in the power cable to the AC.
If the PSU is working the light bulbs should light bright, and remain ON.
Measure the Va voltage and it should be correct if the PSU is working.

Generally, if the PSU is clicking this could mean the PSU is good.

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

dick_barton

I’m not aware of any component failure relationship(s) between the boards and none of the threads I have read up until now have indicated such. Do you have any further info on this possibility?

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Andrew F. Ali ~

Thank you for explaining that PSU test. I am going to try it. It’s the kind of test I need to learn how to do and to perform regularly on various power supplies in order to assist in efficient troubleshooting.

I just looked online for about a half hour for a good video that would illustrate this test even further, but couldn’t find one. Would you happen to have a link you could send to me here of a video showing the process? Helps me to see it in that “moving” form, along with the written form. Thank you in advance for looking.

~ kca

[dick_barton]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

dick_barton

I’m not aware of any component failure relationship(s) between the boards and none of the threads I have read up until now have indicated such. Do you have any further info on this possibility?

I did look through the threads but could not find the link. Can you post photo's of those two little boards as best you can and hopefully it will jog someone's memory. Maybe there is a part number on the boards which could help to find the thread regarding the failed capacitors.

[tvtimmy]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

replace the caps you marked in yellow.

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Okay. I will get those caps today or tomorrow.

The two brown ones on the left are: 470uf 35v

The four green ones on the right of the heat sink are: 1000uf 35v

And the two brown ones on the right of the heat sink are: 2200uf 10v

But what is the lone green one? The one that sits above the 4 green ones. I cannot read the label. Looks like maybe 470uf 100v? Just can’t tell. Do you know or remember from your previous repairs?

[tvtimmy]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

I dont recall the specs of that cap, got a board at home, but Im away. Bump up the 10v caps to 25 or better yet 35 volts.

[kca]

Re: Samsung HP-T4264 ~ Clicking and no picture or sound

Okay. Will do.