Dac-19m009

[ndawgtkd]

I have an old Samsung display that the CCFLs broke in. I decided to go the route of converting to LED instead of ordering new CCFLs and installing. At this point in time I have the board wired to the PSU's output pins to the display board. I found a 13.8V source (LED inverter shows that it needs 10-30V), and a ground, as well as outputs silkscreened to say:

EVA (Could be EUA)
DET
ADJ

My assumption is that Dimm would be jumped to ADJ and On would be jumped to DET.

I got everything wired up and turned on, and the LEDs flash momentarily and the PSU seems to shut off. I'm not sure if the LED inverter is drawing too much current from the 13.8V pin that I'm using. Any assistance would be greatly appreciated, the monitor runs fine without the LED driver installed.

[budm]

Re: Dac-19m009

Are you sure the EVA is not actually ENA (ENABLE) which is the Backlights ON/OFF control receiving pin? You should also use 470 ~1K Ohms resistor ins series with the control wires just in case you connect them wrong.

[ndawgtkd]

Re: Dac-19m009

The 2nd character doesn't look like it could be an N, but I suppose it could be a mis-print. To test I wired the enable directly to a 5V source, but I ended up getting the same results, as soon as the LEDs power up the PSU turns off.

[budm]

Re: Dac-19m009

What does the instruction sheet tell you about those 3 control pins?
Is the ADJ pin for PWM Dimming control or Analog Dimming control?
We need more info about the board.
And the Dac-19m009 control signals, is it Active low or active high?

'At this point in time I have the board wired to the PSU's output pins to the display board' Do mean the Main logic board? That will be low current supply, not for driving the backlights circuit. It should be powered from the output supply that goes to the inverter circuit and you also need to remove the MOSFETS from the inverter circuit or REMOVE THE FUSE for the power supply feeds the inverter section.
Pictures will help.

BTW: DAC-19M009 ??, REV ???

[ndawgtkd]

Re: Dac-19m009

What does the instruction sheet tell you about those 3 control pins?
Is the ADJ pin for PWM Dimming control or Analog Dimming control?
We need more info about the board.
And the Dac-19m009 control signals, is it Active low or active high?

'At this point in time I have the board wired to the PSU's output pins to the display board' Do mean the Main logic board? That will be low current supply, not for driving the backlights circuit. It should be powered from the output supply that goes to the inverter circuit and you also need to remove the MOSFETS from the inverter circuit or REMOVE THE FUSE for the power supply feeds the inverter section.
Pictures will help.

BTW: DAC-19M009 ??, REV ???

What does the instruction sheet tell you about those 3 control pins?
Is the ADJ pin for PWM Dimming control or Analog Dimming control?
We need more info about the board.
And the Dac-19m009 control signals, is it Active low or active high?

The LED inverter board is CA-155 REV:02
DAC-19M009 AF Rev 01A

From the information I can gather online:
ENA - enable / disable the backlight 0 - 3,3V (yellow)
DIM - adjust the brightness of the LEDs 0,8 - 2,5V (yellow)

I'm not sure how to determine if it is PWM or Analog, nor am I sure if it is active low or active high. I am connecting to the pins that feed the logic board, that probably explains why the PSU shuts off after the LEDs turn on, but works fine with them disconnected. In the PDF provided would I be connecting my input voltage to the 14v B+ or one of the other 14v supplies once the fuse is removed? Also, would I still be connecting my control pins to the low current - logic side of things?


With the unit powered on and logic board attached I am getting the following readings:
ADJ : 7mv
DET : 3.127v
ENA, EVA, or EUA : 2.994v

The PSU with the logic board removed has the following readings:
ADJ : -2.357v
DET : 52mv
ENA, EVA, or EUA : 50mv

Hopefully these values help answer your questions, thank you very much for your help, the chinese instructions weren't exactly very helpful

[ndawgtkd]

Re: Dac-19m009

The board looks almost identical to the board that you posted, however it does have the bottom portion populated with an audio control circuit. I removed the glass fuse that was listed on the pdf, is there anything else that I could / should remove from the board? I am seeing 22 volts at the 14v B+ probe point, and I hear a high pitch whine coming from the PSU when disconnected from the logic board, is this something that I should be worried about?

[ndawgtkd]

Re: Dac-19m009

I don't have a great grasp on reverse engineering power supplies, so please bear with me. I found an old thread that you assisted with as well referencing removing the transformer and 8-pin mosfets. From what I could translate from online it looks like the 2 transformers and 2 8-pin chips next to them in the upper left of the board are what you're referring to, correct?

[ndawgtkd]

Re: Dac-19m009

I removed the 2 transformers, the 6 blue caps, the fuse, and the 2 8-pin mosfets. I now no longer have +5v at the output to the logic board. I still have 14v on the 13.8v pin. I replaced all removed components, however there is still no +5v. Any suggestions?

[budm]

Re: Dac-19m009

Since your board is not the same version as the one I provided with the PDF, we will need really good clear pictures of the top side and the bottom side of the board to figure out how the power supply outputs are generated.
You need to recheck all the rework you have done to get the 5VDC back first.

[ndawgtkd]

Re: Dac-19m009

Hey Bud, I will take pictures of my specific board when I get home today, however here are some high-res photos of yours that I found for this particular board, same revision and version:

http://s807.photobucket.com/user/bud...?sort=3&page=1

I removed the 2 transformers in the upper left of the board, the 6 blue capacitors, and the 2 8 pin chips, as well as the fuse and the 4 lamp ports shown here:
http://s807.photobucket.com/user/bud...ml?sort=3&o=19

I realized that I no longer had +5v so I replaced the 8 pin chips, transformers, fuse and capacitors. I have not yet replaced the ports themselves. I will do so when I get home today.

[budm]

Re: Dac-19m009

Those two 8-pin Power MOSFETs has to effect on the 5V supply, the power supply board is an always on power supply, the 5V and the 14V are generated by the same power transformer and the drive circuit.

[ndawgtkd]

Re: Dac-19m009

Ok, so in that case I should go with the original suggestion and run it with the fuse removed, but the transformers and mosfets installed? Could I have damaged anything by turning on the supply with the fets, transformers, and caps removed?

[budm]

Re: Dac-19m009

BTW, to disble the inverter circuit all you have to do is to remove those two power MOSFETs (8-pin DIP) and leave everything else in place, then you tap the 14V to run your new board at the output side of the fuse for the inverter circuit.

[ndawgtkd]

Re: Dac-19m009

I removed the rest of the components to try and make room for the new inverter board, but it seems somehow I damaged the 5v circuit in the process. Can you clarify your previous reply, 'Those two 8-pin Power MOSFETs has to effect on the 5V supply' Did you mean 'no' effect? Sorry for my ignorance. I'm trying to understand as best as I can.

[budm]

Re: Dac-19m009

I removed the rest of the components to try and make room for the new inverter board, but it seems somehow I damaged the 5v circuit in the process. Can you clarify your previous reply, 'Those two 8-pin Power MOSFETs has to effect on the 5V supply' Did you mean 'no' effect? Sorry for my ignorance. I'm trying to understand as best as I can.

Sorry for the typo, they do NOT have any effect on the 5V supply.

[ndawgtkd]

Re: Dac-19m009

Thanks for the clarification. I've poured through the schematics for the DAC-19M008 and 005 boards as well as several other forum posts, since I can't seem to locate a schematic for 009 and I believe that I have a slightly better understanding about what is going on. I will take a shot at it tonight and post by my results. Thank you very much for your patience, clearly I only have a very rudimentary understanding of what I'm doing and I really appreciate you pushing me in the right direction.

[ndawgtkd]

Re: Dac-19m009

I got the LEDs working, but now I have no picture. This thread can be closed, I will open a separate thread to troubleshoot the LCD.

[budm]

Re: Dac-19m009

Did you verify that the cable between the LCD panel and the main /logic board is properly connected?
Pictures of that show how all the boards are connected?

[ndawgtkd]

Re: Dac-19m009

Budm, I started a new thread to address the LCD, pictures will be posted there shortly:
https://www.badcaps.net/forum/showthread.php?t=55534