Samsung LE32A457C1D blinking LED

[Baserunner]

So a few years ago this tv died and after a while I decided to try and repair it by replacing some caps. Unfortunately did didn't do the trick so I bought a new tv and let the broken one sit for a while. Still, for me it would be a good project to try and fix it one more time, to learn and give it to my girlfriend when it finally works

The last couple of hours i read some threats on this forum but couldn't come to a conclusion as how to approach this problem.

So the tv doesn't turn on, also the backlight doesn't work and the power LED blinks a few times, after that it just stays on (like it normally does in stand-by mode). As said before, most of the caps on the power board are replaced.

What steps should i take?

Here are some pictures

[martino]

Re: Samsung LE32A457C1D blinking LED

first off,remove the yellow goop around the legs of those components,it can become conductive over time.
Then it's time to get the multi meter out.
Do you get a proper 5volt standby on the connector that goes from the power supply to the mainboard?
Can we get a better picture of that connector,so it clearly shows the legend printed by it?

[Clydeuk]

Re: Samsung LE32A457C1D blinking LED

Not sure if it was this series or not as I'm on mobile broadband and can't load the pictures, but certainly on some of these sets the faulty power supply (prior to cap replacements) damages the EEPROM i.c on the main board causing similar problems. I'm not at home to get the location but it's something like a 24C64 or 24C128. The good news is that you can fit a new blank one and it will be programmed on first start up.

If the caps you replaced were visibly vented on top this is a strong possibility.

[budm]

Re: Samsung LE32A457C1D blinking LED

There are labels next to those whit connectors, report the DC Voltage readings of each pin and make sure to put the pin names on the reports.
See the diagram for the board BN44-00214A attached.

[pauls7]

Re: Samsung LE32A457C1D blinking LED

Hi, I seem to have a very similar situation...

Samsung LN32A450C1DXZA, Dong Yang BN44-00214A, won't power on.

Power issues manifested gradually, but now I can't get anything. Plug in, standby light comes on. Press power, standby light blinks 5 times and then goes out. Screen never comes on.

Here are my readings after plugging in and pressing power:

CMN801

BLU 5.3
ADM .67
PWM 0
GND 0
+5 5.3

CMN802

PS 3.95 NC X
SB 5.3 GND 0
GND 0 GND 0
12.8 12.25 12.8 12.26
GND 0 GND 0
GND 0 GND 0
5.3 5.3 5.3 5.3
5.3 5.3 5.3 5.3
GND 0 GND 0
12V 11.95 GND 0
12V 11.95 12V 11.95
NC X NC X

CMN803

24V 24.5
24V 24.5
24V 24.5
24V 24.5
24V 24.5
GND 0
GND 0
GND 0
GND 0
GND 0
NC X
BL 5.3
ADM .67
NC X

No obviously bad caps, but I replaced CM856, CM858, CM861, and CM868 anyway.
Another thread mentioned a FET with bad solder joints, so I reheated them and checked all the others.

No joy. Suggestions welcome...

Thanks!

-Paul

[pauls7]

Re: Samsung LE32A457C1D blinking LED

Bump

Any ideas about what to do next? Does 5 blinks have any special meaning?

[budm]

Re: Samsung LE32A457C1D blinking LED

The power supply is getting correct voltages from the main board and it puts out correct output voltages.
Did you check the DC Voltage at the SMD FUSE on the T-CON?

[pauls7]

Re: Samsung LE32A457C1D blinking LED

Hello Bud,

Thanks for the reply. I'm not sure what I'm looking at. I see a power board, tuner board, inverter board, and a smaller one as shown below. Is that the T-CON? I don't see anything that looks like a fuse on it. Thanks!

-Paul

[pauls7]

Re: Samsung LE32A457C1D blinking LED

I see 2 fuses on the inverter board, and both check out OK.

Maybe I should change my introduction to say that I like fixing things where the problem is easy to find...

[Shinju]

Re: Samsung LE32A457C1D blinking LED

Curious as I did t see this mentioned, Did you unplug the mainboard from the power supply and plug the panel in to see if the PS kicks on the backlights? I know this works on all Samsung Panels that have the inverter/power supply combo board. I haven't had one just a PS and separate inverter boards in quite awhile.

[Neelix]

Re: Samsung LE32A457C1D blinking LED

That's the T-CON board yes. In your picture, FP1 is a fuse

[pauls7]

Re: Samsung LE32A457C1D blinking LED

@Shinju - I've tried that, but there's still no backlight.

@Neelix - So, what I circled below is a fuse (not a cap)? The ones on the inverter board are bigger, white, and marked 5A/160V. With power on, I get 11.86V across that one, which would make it bad, and I'll need to figure out what to replace it with. Sound about right?

[pauls7]

Re: Samsung LE32A457C1D blinking LED

So, I get the idea that the fuse is not what I indicated, but the smaller, black one marked "UD" just above it. That seems to test out fine.

[budm]

Re: Samsung LE32A457C1D blinking LED

Can I see the pictures of the inverter board?
Is this the inverter board you have?
http://www.shopjimmy.com/samsung-lj9...t-inverter.htm
Can I also see the whole back side of the TV so I can see how all the boards are connected?

[pauls7]

Re: Samsung LE32A457C1D blinking LED

The inverter board is a CMO T871029.14

Let me know if you need more...

[senndogg]

Re: Samsung LE32A457C1D blinking LED

Con you resolder the legs of this transistor? Give it a try, simple job.

[budm]

Re: Samsung LE32A457C1D blinking LED

Oooh CMO Inverter board, need to check the small black fuse.
Is this the correct model of the TV? SJ does not show that inverter board for your model?
Please get the P/N as printed on the inverter board and a closed up pictures.

[pauls7]

Re: Samsung LE32A457C1D blinking LED

TV is Samsung LN32A450C1DXZA
PS is Dong Yang BN44-00214A
INV is CMO T871029.14
TCON is CMO V315B3-L04

@senndogg - QB802 has been resoldered, no change.

@budm - I checked 5A fuses F2 & F3 on the inv bd, OK. Looking for the small black one as you said, I found .75A fuse F1 near the connector. Seems to be bad. I will replace and test.

Thanks much.

[budm]

Re: Samsung LE32A457C1D blinking LED

TV is Samsung LN32A450C1DXZA
PS is Dong Yang BN44-00214A
INV is CMO T871029.14
TCON is CMO V315B3-L04

@senndogg - QB802 has been resoldered, no change.

@budm - I checked 5A fuses F2 & F3 on the inv bd, OK. Looking for the small black one as you said, I found .75A fuse F1 near the connector. Seems to be bad. I will replace and test.

Thanks much.

That is, that little black fuse (for the backlights PWM IC) is the common failure in the CMO Inverter board.

[pauls7]

Re: Samsung LE32A457C1D blinking LED

Indeed it is. I don't have a replacement handy, so I rigged up a way to test it and the TV popped right on.

Many Thanks