Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

[budm]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

Did you use low ESR cap for C102?

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

I used a tantalum capacitor like the one pictured here:

I made sure I put it in the right way

I went to three separate electronics stores and just couldn't find the tiny SMD caps. Why is it so hard to find those outside of the internet?

Did I screw up by using a tantalum cap?

[Andrew F. Ali]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

From what I've read so far...I think your backlights could be bad....

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

I ordered a main board. I just don't have the time or patience or remove and install a new component that might or might not work. If the main board doesnt work, this thing is going into a landfill. I will update the thread once I receive and install the new main board so people googling in the future can get a sense of what I did.

Thanks for taking the time to help me out, everyone

[dick_barton]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

Did you have a 1K resistor connected as shown in Post #11 and also another 1K resistor as shown in Post #18 to test the backlights. (Two resistors needed for the test.)

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

So in the previous 2 posts I put the resistors in individually while keeping the other cable plugged in. This time I put the resistors in both cables at the same time. I got a backlight after the initial click that lasted roughly 3 seconds then it clicked off and did not return. When I unplug and wait 10 seconds to plug it back in again, the same thing happens.

Can a backlight be bad, even if it comes on for a few seconds?

I attached a pic of the light I saw shining through the back when I plugged the set in.

[dick_barton]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

I think it's an inverter fault and the set is powering down on error.
What is your power supply board number eg BNxx-xxxxx and inverter board make and model number.
If you could add your pictures to your post as attachments rather than on another site would make it easier.

[dick_barton]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

There's a ribbon cable on the inverter board. Where does the other end connect.
Can you post a picture of the text alongside where the ribbon connects to the inverter board and also a photo of one of the transformers on the inverter board showing the numbers printed on it.

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

The ribbon cable runs to what looks like another inverter on the opposite side of the tv set as seen in picture 1. It runs along the bottom of the tv.

The model of the power board is BN61-03012A #6 DH06 as written.

I attached other pictures. It looks like the inverter model numbers are SSB520H24V01 REV0.3 I had to disconnect two cables to see the model number but I reconnected them afterward.

The transformers seem to have the number 388R B0829 printed on them.


I also took a picture of the text next to the ribbon cable connection.

[dick_barton]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

So you have a Master & Slave inverter boards with one connected across to the other.
Can you measure the DC voltage on pin 1 (yellow arrow) when you first switch on and when the backlights go off and that you also have 12V on pin 5.

[dick_barton]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

All the transformers should be connected in series as shown in the photo.
Follow the yellow arrows and check that all the transformers on the circuit board are connected in series. Set switched off and meter set to ohms.
Check both the left-hand and right-hand inverter boards.

[dick_barton]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

Again with the set off, set your meter to continuity and check that the cables connect the two halves of the boards together and that there's no bad connection. Repeat for the other inverter board.

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

PROT1_1 reads 0.027V, but quickly jumps to 11.26V when it clicks and the backlights come on, only to quickly fall back down to 0.027V

VCC(+12V) reads 12.08V

EDIT:will check the transformers being connected in series after some dinner. This troubleshooting is exhausting

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

All the transformers should be connected in series as shown in the photo.
Follow the yellow arrows and check that all the transformers on the circuit board are connected in series. Set switched off and meter set to ohms.
Check both the left-hand and right-hand inverter boards.

regarding this post, should I hold one lead in the first arrow then use the second lead to test the other arrows sequentially? The first pair of errors gave me an OL signal as much as I tried to wiggle them and make good contact. The second pair of arrows gave me 2 ohms.

I tested the cables joining the two halves and the continuity is there for both left and right sides

[budm]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

The long board connected to the lamps are the Balancer boards, the High Voltage inverter section is on the power supply board.
There are pin labels for that small connector of the Balacner board, what are the labels for those pins?
Are they VCC, FB, and LD?

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

if you are referring to the tiny connections between the upper half and the bottom half then its labels are

GND
FB
VCC(+12V)
PROT
LOOP2
LOOP1
PROT1_1

thanks for clearing up the inverter/balancer nomenclature. One step closer to knowing what the heck is wrong with this thing and how I can get a shiny new 52 inch to watch tv on.

[budm]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

The thing is, is the TV still clicking away?
And when the backlights come on, do you see any image on the screen?

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

Yes, unfortunately the clicking is still there

I did check for an image when the backlights came on and there wasn't any, simply the glow from the light. Those moments when the backlights werent on, I also shined a flashlight into the screen to see if there was an image in there somewhere and that also didn't produce any results.

I think I'm just going to wait for that main board to arrive. This is way too much time to invest on this project at this point.

[Bertron]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

So here's an update.

I received the new main board in the mail, swapped it out, double checked all connections and now I get a loud squealing out of the speakers and the occasional samsung startup noise before it shuts down. It does this repeatedly with no image. Going to poke around a bit, but at least I am getting something apart from just clicking on this set.

Ideas? Does the squealing and startup 'jingle' provide any clue as to what it might be?

[dskall]

Re: Samsung LN52A550P3FX2A, blinking red light in front. No backlight.

Ya lol change c102 should fix problem