Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
PlainBill, Jetadm123 > Thank you both for sticking with me and still suggesting things I can try.
Ken256 > Thank you, that sounds like a good idea to try! I'll do that ASAP.
However, my wife and I are going on vacation for 14 days starting this thursday, so I have to pause this project. I will post back in this thread when I'm back and I've tried your suggestions.
Best regards
René
reneg
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Last Activity: 01-31-2011, 06:34 PM
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
I measured the voltage on all of the pins on the IC (Whew! Glad I had a magnifying glass!) and wrote down my results. I wrote them on the diagram of the IC from the data sheet. The only pins that changed voltage when I pressed the power button was pin 10 and (maybe) pin 29. It seems pin 10 is the one receiving the input from the power button. When I'm not touching the power button, the voltage was 3.12V and when I pressed the power button, the voltage decreased to 0.55V.
Pin 29 had 3.13V when I was not touching the...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Thank you for your replies!
PlainBill, do you mean the IC I've taken a macro shot of? It's a Realtek RTD2120L. I found the data sheet and have attached it. The main IC is a Realtek RTD2549T. I couldn't find any data sheet on it, but I managed to find one for a RTD2523. I thought it would be better than nothing as they do look similiar. The data sheet is available here: [url]http://cnpdf.alldatasheet.com/datasheet-pdf/view/202712/ETC2/RTD2523.html[/url]
The two IC's to the right of the main...Last edited by reneg; 01-08-2011, 08:17 PM.Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
* bump *
Is anyone able to get any meaning out of the measurements I've made? Does it tell you anything?Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Thanks for tuning in! :-) I'll keep these things in mind, but right now it seems the problem lies with the logic board, as there is no signal going out to the power supply board to start the CCFLs. But it's good to know what else to look for if we find out the logic board is fine. Thanks. :-)...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
I measured on the right side of R95 and it had 3.11V constant. When I pressed the power button, the voltage decreased to 0V. On the left side of R95 it decreased to 0.55V.
I measured on the right side of C32, but there was 0V. And when I pressed the power button, still 0V.
I also tried measuring on the different components that are attached to the LEDs, but nothing happens when I press the power button. However, when I measure voltage inside the purple rectangle, sometimes the voltage...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
I did some more testing and found out that R95 is connected to pin 8, which is connected to the power button. And after R95 comes C32.Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Okay, C33 is connected to pin 3 starting from the bottom, which is connected to the orange LED (Standby LED). C34 is connected to pin 2, which in turn is connected to the green LED (On LED).
Do you think the logic board shuts down because the LEDs don't work?
Actually when testing, it seems the orange LED itself works OK. It's okay bright when I'm testing resistance. But the green LED hardly lights up. However, I guess other factors might be in play here.Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Okay, I've attached my measurements. It was not easy to measure. I had to do some scraping on the solder joints on each side to even get a reading. Here are some comments to the results:
C33: I could not get any connection on this one. Even on 2.000M ohm, and scraping and scraping, trying different places on it and so on. Nothing. Absolutely nothing.
C34: This gave me a reading first, but when I double checked and triple checked, I could not get a connection no matter how hard I tried.
...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Okay, I'll do that tonight. However, I'm sure someone once told me it was risky to measure resistance on a PCB, as there was a possibility of damaging some of the components. Is that incorrect?Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
I really appreciate you taking the time to help me with this. Thank you so much for your patience!
However, I might need a little more guidance. When you say surface mount caps and resistors, do you mean these I circled? Or by caps, do you mean the bigger ones more to the left? And should I just measure resistance in the capacitators and expect it to be larger than 0 for it to be OK?...Last edited by reneg; 01-03-2011, 04:48 PM.Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
All the buttons get 3.11V, measured right on the solder joints next to each individual button.
I did a pretty thorough scan through the logic board but found zero fuses.
I was wondering if my problem could be caused by bad ground connection? Two of the holes to the groundscrews looks a bit wrecked. I've attached photos of the holes....Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Okay, I tested the all the pushbuttons and they are working correctly. I tested all of them by placing my probes on the two terminals (They have 4, but it seems only 2 of them are connected) and when I push the button, the resistance is 0 ohm. I also tested the connection from the power button to the logic board, by placing the black probe on the solder joint to the negative/ground wire in the connector on the logic board, and my red probe on the solder joint which is connected to the correct wire in the connector on the...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Okay, the coil says 1.76V on the opposite side. When I held the probe, it sometimes said 1.78V, but it was pretty stable on 1.76V. I measured by trying to hit the solder joint on the PCB where the wire from the coil was joined.
I measured the ON OFF pin, and imediately after I switch the flip on the power supply board, it says 0.03V on it. I measured it while pressing the POWER button on the front, but nothing happened, the output was still 0.03V.
So I guess that tells us that the logic board doesn't...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Okay, pin 2 has 5V.Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
When you say pin 2, where do you start counting? I don't think I can trace the pin on the board, as it seems some of the 'lanes' are inside the PCB. But I will measure it.
Thank you so much for your help and patience, jetadm123!...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
Great, thanks for the tip! I measured the 3 pins (Even though the middle one is not connected to anything) and got the following results:
Pin 1: 4.99V
Pin 2: 3.30V
Pin 3: 2.05V
(I've numbered the pins in the attached image)
Jetadm123 > The part number is "Z1010AI ZD7P14". Yes, you're right, the connector circled yellow is for the buttons on the front, and to the USB board. (There's 2 wires going from the USB board power connector to...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
I took a closer look at the component and the part number says "1084 0706AL". It's really hard to measure when the PCB is screwed onto the frame with the power supply, as the component is almost inaccessible and there is no soldering point on the opposite side of the PCB. How would you advise me to proceed; should I unmount the PCB and manuelly connect the 4 screwholes in the PCB with the frame using a wire? Or can I measure this without the PCB being grounded, as long as just my black probe is ...Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
I've just tested those two, and they have between 0.03 - 0.05 ohm.
I looked around but couldn't find any other fuses on the board.Leave a comment:
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Re: Sun 24.1" LCD monitor (Samsung LTM240M2 L02 panel)
I've been doing a little reading in some other threads and learned that I used an incorrect way of measuring the voltage. I read I should connect minus (-) to the frame or ground, and then put the plus probe on the pins on the connector. Also, it was mentioned that absolutely everything should be connected in order to be able to trust the readings 100%. So I connected everything and redid my measurements, and here are my readings.
5V standby: Both pins have 5V from the frame to the pin.
5.3V: Both pins...Leave a comment:
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