Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

[landen_michael77]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

When the tv turns on it jumps up to around 4.9mv then back down to 2.5mv. Takes about as long as it does for the the lights to turn on and off.

[budm]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Are you sure it is in mili volt (mV) range? If you see the backlights turn on for seconds, it cannot have only in mV showing on pin 12 (ENA) PIN.

[landen_michael77]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

correction starts at .002v spikes at 1.2v then back to .002

[budm]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

That means the main board is not working.

[tom66]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

If it's any help, I'm pretty sure I had the same issue with the Samsung LE32N73BD. The backlight would fire up, dim slightly, then shut down. I hoped for an inverter issue, but it was the main board that was shutting the backlight off. I pulled BLON and DIM high, and I got to see one or two frames of analog snow on the screen just as it shut off, so I figure it was crashing after sending the first image to the t-con... but I never did sort the issue out sadly, sold it for parts.

[budm]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

I had to change the main board on my due to bad pictures. At fist I thought it was the T-CON, but new T-CON did not fix the problem.
http://s807.photobucket.com/albums/y...g%20LN-T3242H/

[landen_michael77]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

i have another main board but the tcon cable is different. All the other cables are identicle.Is there anyway I could swap it to check for sure. Actually looking now I have the other tcon board as well. But the connector to the main board is different. And the inverter board but it is green not blue, and the there are more transformers......Update. Hooked up other main board. Everything except tcon cable. While tv is in the "on" mode I have a steady 5v on the ENA (#12)pin on the inverter board. lights still 2 seconds to black.

[budm]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

That can be the reason for 2-sec to black if the inverter board uses the PWM DIMMING instead of analog diming, if it uses PWM_DIMMING, it will need that signal for the lamp to stay on. Probe the PWM_DIM pin and the A_DIM pin. The PWM pin will have 100~200Hz AC signal, A_DIM will have DC 0~5V for dimming, they can only use or or the other, you cannot feed both signals to the inverter board. If you look up the LCD panel spec, it will give you the signals details.

[landen_michael77]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Pin #13 (DIM) reads 3.5v steady while "on". I dont think my meter has Hz. I think maybe I should purchase a better meter. All I have is this little pocket-pro DM-2A. Any suggestions for someone who wont be using it on a daily basis.

[budm]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

So the substitute board has the same signal labels for the connector that goes to the inverter board as the original? They have to match the signals. The DIM on this board is more likely to be the _dim, and the pin 14 EX_DIM may be for PWM dimming, that is why you need to look for the spec sheet of the LCD panel to find out.
OK, so you do have 5V on ENA pin, and 3.5V on DIM and 24v, then the backlights should stay on.

[budm]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Here is the LCD panel spec based on shopjimmy listing. Pin 14 is not used, it only has Analog dimming control, see page 16. So it does have all the required signals (Ena/BL_ON and Dim) and 24v feeding it and it still black oit, the you still have problem with the inverter board or lamps since you sub board is providing the correct signals now. So youhave at least two problems; Main board, inverter/or lamp problem.

[landen_michael77]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Should I disassemble, and check the bulbs. I have done this to monitors bfore.

[mlepner]

Re: Samsung LNT3242H 32" LCD TV, bad fuse on inverter?

Try measuring across 1-3 and 2-4 instead. Your meter should on 20kohms, if it is manually ranging.

Hi, This is the original poster of this thread. I followed your suggestion above that you made to Michael earlier in the thread and below are my results.

I measured all 8 transformers (T1 through T8) on my inverter board (Samsung LNT3242H) using your method quoted above (red probe on 1, black probe on 3 and then red on 2 and black on 4). Below are all the readings for the transformers:
T1
1-3: 3.8
2-4: 0.9
T2
1-3: 3.8
2-4: 0.9
T3
1-3: 3.8
2-4: 0.9
T4
1-3: 3.8
2-4: 0.9
T5
1-3: 3.8
2-4: 0.9
T6
1-3: 3.8
2-4: 0.9
T7
1-3: 3.9
2-4: 0.9
T8
1-3: 3.9
2-4: 0.9

Then I used the multimeter to do an audible continuity test on the 3 fuses on my inverter board (2 white labeled F1 & F2, and one black fuse labeled F3). F1 and F2 fuses gave audible feedback on the meter, but the F3 black fuse did not give an audible noise. On the F2 fuse, I put the probes on the ends of the fuse itself, and then the metal bulges directly above and below the fuse and neither method gave an audible response on the meter.

Could the F3 black fuse be the cause for no picture? Is there a way to replace/repair it without replacing the whole inverter board?


Thanks again for the help!

[tom66]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

F3 could easily cause this issue.

[mlepner]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Thanks for your input, Tom.

I'm not familiar with how to replace this broken fuse on the inverter board.

I have basic tools. I don't have a soldering iron, but if needed, I can get one.

If you have any instructions on how I can swap out the bad F3 fuse for a new one, I would be much obliged. If it's easier to start a new thread asking about how to repair the part, I could do that as well.


Regards

[tom66]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Yeah, you will need a soldering iron.

Simply flood the device with solder, and the device will move with a little pressure.

Then place the new device on board, tack one end, then the other.

[budm]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Looks like another CMO inverter?

[tom66]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Looks a little like a CHUNGHWA (Chunghwa Picture Tubes) CPT inverter. Chungwha don't make LCDs any more. Interesting case of a CRT manufacturer (hence "Picture Tubes") retooling to make LCDs. But they only make 15" or so modules now, previously up to 40".

[mlepner]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

Based on some of the comments on inverters, should I just replace the whole inverter rather than try to change out the fuse and possibly have additional problems in the future?

Or is it worth trying to fix the fuse first? Then, if that doesn't work replace the whole inverter?

[tom66]

Re: Samsung LNT3242H 32" LCD TV, no picture but audio works- no component damage

I would definitely try the fuse first.