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Aric, Technician
Category: TV
Satisfied Customers: 44230
Experience:  15+ years in the field. Owner of AV Installation, OEM and Repair company
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I have a Samsung hps4233x/xaa with no picture. sound works

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I have a Samsung hps4233x/xaa with no picture. sound works fine, just no picture at all. I have replaced the main board and still no picture. can you help?
Hello and thank you for the question.

When you power the set up, do you get anything on the screen- distorted image, MENU, or Input icons, etc.?

If not, is the screen actually priming (meaning slightly lighter than when the set is off)?

Also, what prompted you to replace the mainboard if the sound was working fine?
Customer: replied 3 years ago.

The screen remains dark when I power it up, even in a dark room. I am unable to see any menus, images or anything at all. I can hear a click and startup tones as if the the mainboard is waking up. I replaced the mainboard as an uneducated wild guess of my own - ok so I don't get bragging rights.


I am sitting in front of it if there are any test you may need...

Thanks for the reply Nate. The most common cause of this problem would be the Power Supply Board not the Mainboard, however the only tests we can do to isolate it for certain, is to use a Meter and open up the set and test for your Va, Vs and low voltages from the power supply. We also need to check the Sustain board heat sinks to see if any are reaching normal operating temp. If you have a meter, let me know what you find for these voltages. Or if you're simply looking for the most common cause of this problem, let me know and I will attempt to locate a power supply board for you.
Customer: replied 3 years ago.

Have meter, no problem Va = 122, Vs = 122


Not sure of the other locations of the low voltage and temp


The heat sinks to the right and left of the power board are two degrees above room tem at 67 F


When turning on the set I do notice a red led on the power button that blinks four times if it helps.

Thank you. The red light on the power button should blink 4 or 5 times on the initial startup I believe.

It's not blinking over and over again, is it?

Also, what you'd want to do is let the set stay powered up for about 20 minutes, then check the heatsinks on both Sustain boards and see if they warm up.
Customer: replied 3 years ago.

led just blinking four times. the set has been powered up for about 45 minutes, no change in temp


Okay, are the heat sinks the same on both of the large Sustain boards- not warming up at all?

Additionally, on the Logic Board (which is the small squarish board located at the lower center of the panel), do you see a steady lit green light, or blinking green light?
Customer: replied 3 years ago.

The heat sinks are not warming up on either of the Sustain boards.


I am not sure which is the logic board, but there are no led lights lit on any of the boards, as viewed from the back. I even turned the lights off in the room and looked and no leds lit.

The Logic Board is below:


It operates off of a 12 or 15 volt DC output from the power supply. It's possible that the supply voltage is missing, as the Logic board drives the Sustain boards.

Customer: replied 3 years ago.


The board in the picture you linked to is not in this set. I looked it over, but I can not find that one here. The white wires off of the power supply board go to a board marked BN96-01856A

That board is the sub power supply. Can you please take a picture of the back of the TV and post it here?
Customer: replied 3 years ago.

See if this helps...


Okay, it appears the Logic is part of the Mainboard on this set.

So, we have Va and Vs voltages, but none of the heatsinks get hot and the screen does not backlight even for a second is that correct?
Customer: replied 3 years ago.



Va, Ve, Vs, Vset, Vscan are all 122 at this point. with the set on



Heat sinks on the power supply board are between room temp and 93F


Sinks on the Sustain boards are room temp

That seems high for your Va. Do you see a terminal labeled Vs or Vsus?

Also, do you see any voltage specs for Vs or Va labeled on the back panel of the TV, or a sticker anywhere else?
Customer: replied 3 years ago.

Vs = 122 (Which is the house voltage)


Chart found on power supply board attached


Vs should be between 180-220 Volts DC (not AC). Vs should not be house voltages which is 110-115 VAC.
Customer: replied 3 years ago.

Ok so are we saying that it is the power supply board that needs to be replaced? And if so could you provide a link to order one?

One last check to try, is disconnect the set from power, then disconnect the two sustain boards from the power supply. Plug the TV back into power, then turn it on and test the Vs once more. We want to see if the supply is faulty, or if the Sustain boards are shorted and pulling it down.
Customer: replied 3 years ago.

After unplugging the Sustain boards Vs still reads 122 v

Okay, your Vs is low by about 100 volts, and this indicates that the Power Supply is not providing the correct voltage and should be replaced. If you need further assistance let me know and please do not forget to rate my service once satisfied.
Customer: replied 3 years ago.

Ok, one last question


Can you provide a link where I can get this at a reasonable price?


Preferably someplace that takes PayPal for safetys sake.

First I want to say that board is going to be extremely rare, whether the site takers Paypal, or is a reasonable price is beyond my control. I can only tell you what it takes to repair the TV.

Below are the links I was able to locate the board from:



If you need further assistance let me know and please do not forget to rate my service accordingly.

Aric, Technician
Category: TV
Satisfied Customers: 44230
Experience: 15+ years in the field. Owner of AV Installation, OEM and Repair company
Aric and other TV Specialists are ready to help you
Hello, I just wanted to follow up with you and see If you've received all the information you needed. If not, feel free to reply back to me and I will continue to assist you. Best regards, Aric
Customer: replied 3 years ago.

Your advice was great, I have ordered the part and am waiting for it to arrive. I guess the ultimate test will be when I install it and see if the set works. Thank you!

Thanks for the follow up, and please let me know what happens when the part is installed.
Customer: replied 3 years ago.

I got the board and installed it, unfortunately its still not working. Umm, what now?

Check for that Vsus voltage again and see what you get please, then let me know.
Customer: replied 3 years ago.

Ok, a couple of updates.


There is a logic board under the metal cradle for the main board. When the set is turned on it has two lights on a flashing green one on the left and a solid green one on the right.


The Vs (as measured on VDC between RTN post and Vs post) is 14.1volts with the set on.


Would this be easier for you on some sort of video conference so you can see what's going on? It is possible as I have a good connection and a camera on my laptop.

There's no video conferencing we can do on here, and it must be done via this chat. The lights on your Logic board are normal, and are telling us the board is working. However, before you stated your Vs was 122, and now you're saying it's 14.1. Is this correct?
Customer: replied 3 years ago.

That's correct.


Though I cant seem to find a Vsus, just a Vs which measures 14.1

But previously your Vs was 122 volts and now it's only 14. It should be around 180 volts DC.
Customer: replied 3 years ago.

Just figured out that I forgot to plug a connector back into the mainboard. After plugging that back in the Vs now measures 13.9 VDC


Should I try to turn the VS-adj up ?



Honestly it's almost 165 volts off, I don't think turning it up is going to fix this. Can you please unplug the set from power, then disconnect and reconnect all of your connections again, then plug it back in and check Vs?
Customer: replied 3 years ago.

Ok After that I measured Vs at 14.2 VDC, not much difference there.


I can switch back to the old power board and re check that one?

Yes, I would do that, because it would appear the new power supply board is worse than the original.
Customer: replied 3 years ago.

Switched back to old power board and double checked all the connections. Vs is now 15.0 Vdc

Nate, something is different from when you told me it was 122. Did you have the meter set to a different setting or something? Is every thing connected tightly, for sure?

Customer: replied 3 years ago.

I do have a different meter. The old one met its demise earlier today when I was working on an outboard boat motor and dropped it in the test tank. (I own marinas for a living) This one is new as I just picked it up today at the local WalMart. I did check it against a nine volt battery and it checks out ok. Possibly the old meter was bad to begin with.


This meter I have set to DCV and I am measuring with the negative (black) probe on the RTN post and the positive probe on the Vs post on the power supply board.

Set the meter to it's highest DC setting please.
Customer: replied 3 years ago.

Ok, it already is on DCV, like what is in the picture in this link


I think that is the highest setting for DC

I'm sorry but this meter isn't giving us accurate readings, so we are unable to proceed. Vs was 122 before, which was still low and currently you only have about 15 volts with either supply. Do you have another meter you can use?
Customer: replied 3 years ago.

I don't have another meter. I did just check it against another power supply I have here and it measures 13.73 VDC on a "Switched 13.8v power Supply" from Radio Shack. The manual that came with the meter says it will go to 600v.


As a contrast test I measure outlet voltage at 123.7 ACV.


I know its not a high dollar meter like a Fluke or something but it should be fairly accurate.


I would check with the old meter but it got hit by the prop in the test tank. Not a chance it even works.

Well I'm out of ideas then. You originally had 122 volts for Vs, and now you have 15. I am lost. I will opt out and open the question for other experts to assist.
Customer: replied 3 years ago.

Is it possible we have two bad power boards?

Hi and welcome,

Thank you for the question and your patience. Should you still need assistance for information purposes only...

Initially, to my understanding, there are two (2) SMPS power supply boards on this model; main (something like a P/N BN96-03252A) and DC/DC
(something like a P/N BN96-01856A).



Still, propose to carefully check the DC voltages [presence & consistency] (without adjusting any if the trimpots) and using the metal frame/chassis as common ground:

  • Vs of 200V & Va of 65V on the main;
  • Vset of 195, Ve of 120 and Vscan of -190 on the DC/DC;
  • low DCV of 33V, 18V, 15V, 12V, 6.5V, 5.3V & 5V;
  • PS_ON of 0.0~1.0V, VS_ON of 2.0~5.0V.

Please post back
results / observations.

Customer: replied 3 years ago.


Hi Louie, thanks for your help!

Ok, so far none of the trimpots have been adjusted. The old AC to DC power board (the large one) is installed, and I do have another. Here are the measurements with the negative lead connected to the chassis (where to mainboard groundwire is connected)


Vs = 10.2 dcv

Va = 66.0 dcv


Vset = -1.3 dcv

Ve = .205 dcv

Vscan = -5.76 dcv



I am not sure of where to measure "low DC", "PS_ON", or "VS_ON".

But if you can explain I can follow directions.



The above voltage readings are very low; either a faulty power supply or the power supply is triggered to auto-protect/shutdown.

Please click HERE for the connector/pins of the SMPS main where the voltages may be tested.

While HERE for the connector/pins of the SMPS DC/DC where the other voltages may be tested.
Customer: replied 3 years ago.




Ok connector CN809 on main Power Supply board (the larger one)


1 - 13.4 vdc

2 - 13.3 vdc

3 - -1.0 vdc

4 - 65.0 vdc

5 - 64.9 vdc

6 - -2.5 vdc

7 - -2.5 vdc

8 - -2.6 vdc

9 - -2.8 vdc

10 - -2.9 vdc

11 - 14.89 vdc

12 - 5.24 vdc




Which connectors would you like me to test on the smaller DC to DC board?



None at the moment for the DC/DC SMPS.

What were the readings of the PS_ON and VS_ON please? During standby? When attempting to turn on?
Customer: replied 3 years ago.

I'm not sure where to test that. I can't seem to find that on the board. Where and how should I test PS_ON and VS_ON ?

PS_ON is pin 6 of connector CN804-1 or pin 7 of connector CN810 of the main SMPS.

VS_ON is pin 9 of connector CN810.
Customer: replied 3 years ago.

PS_ON = 1.4 vdc (from cn804-1 pin 6)


VS_on = 3.25 vdc (from cn810 pin 9)

The PS_ON seems a bit high while VS_ON appears to be within limits though confusing since the Vs reads only 10.2 whereas expected is 200.

Carefully disconnect the connector CN5010 of the Y-Drive board (left of the SMPS Main) and then check again if Vs would show a different voltage reading.
Customer: replied 3 years ago.

ok with all cables plugged in Vs = 13.1 vdc


With cn5010 unplugged Vs = 3.47 vdc

Retrun all wires/connectors as originally connected.

Repeat same test but temporarily disconnecting CN4004 of the opposite (right side most) board.
Customer: replied 3 years ago.

With all cables in place Vs = 14.1vdc


With CN4004 disconnected Vs = -0.2 vdc

It would appear to be a faulty power supply.

To my understanding, there is a second PSU board available. Would it be possible to repeat the same test/checks using this second board?
Customer: replied 3 years ago.

I would be happy to but I can see a bad chip on the other board (which was the old one that was original to the TV) so I know its bad. It is the chip at u403 just below the large yellow transformer at the top middle of the board.


The board that is in the set currently was one I got from Tri-State Module and they said they tested it before shipping it out.


Is there a way to verify that it is good?



Please bear with me on a last test on this bunch for now. Re-connect everything and then disconnect CN809 from the main SMPS. Re-check Va & Vs please.

The Service Manual provides a troubleshooting flowchart. Would this serve your purpose?
Customer: replied 3 years ago.

With all connected Vs = 14.0 vdc


Va = 64.9 vdc


with cn809 disconnected Vs = Steadily climbs in voltage about 1 volt per each 5 seconds - this seems weird??


Va = 64.9 vdc

Offhand, the test with CN809 would confirm a faulty power supply.

Still (I know I posted last test above, sorry a few more actually), consider disconnecting connectors to CN804-1 and CN803 from the main SMPS. Then short temporarily pin 4 & 5 of CN804-1. Re-test Vs and Va.

And please click HERE for the Service Manual troubleshooting flowchart for the Main SMP.
Customer: replied 3 years ago.



With cn804-1 and cn803 disconnected and the pins shorted I measured

Vs= 0 vdc


Va = .401 vdc



Shorting pins 4 & 5 is supposed to kick start the power supply. It appears that it is unable to do so.

Replacing the power supply would be the only option left both as an attempt of a fix and as an elimination test.

Customer: replied 3 years ago.

Ok,I will call Tri-State on Monday and have this board replaced. After the new one arrives and its installed I will let you know. Thanks!


Appreciate the update now and again later when able.