Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Krankshaft, I am unsure about what component you are talking about. I have checked the 16 pin driver chip and the mosfet 5 pin, both of which are mounted on the bottom of the board.
Funkhauser
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Last Activity: 11-27-2010, 09:06 PM
Joined: 11-10-2010
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Good catch!
To be honest, I just want to get this thing working! The damage is on the far side of the screen so it shouldn't be a problem. A cracked 24" is better than an old 17" crt!
It is amazing that I overlooked the obvious melted transformer. There is a replacement [URL="http://cgi.ebay.com/TM-09175-Inverter-Transformer-SAMSUNG-LCD-/150501149739?pt=LH_DefaultDomain_0&hash=item230a914c2b"]here[/URL] that I'm going to order. The part should...Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Ok, I've found a camera and took some pictures of the top and bottom of the board. Let me know if the quality is alright....Last edited by Funkhauser; 11-16-2010, 08:27 PM.Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
I put too much pressure on it while closing the casing and now there is a section about 1 inch square of what appears to be damaged pixels. It is hard to describe what it looks like, I held the screen in front of a light source and it looks like thick red horizontal and vertical lines.
Im pretty sure I have not damaged any of the controller board or ribbons so I think it is still in working condition.Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Alright alexanna, I appreciate all the help! I will ask around for a good camera to snag some pictures. Right now I am eyeing [URL="http://cgi.ebay.com/Power-Board-BN44-00226D-IP-54155A-SAMSUNG-T24-T26-/260693222377?pt=LH_DefaultDomain_0&hash=item3cb286e3e9"]this[/URL] ebay auction as my last option.
However, I am sad to say that I damaged the monitor display screen last time I opened it up. It is on the far right of the screen so I hope it is still functional!Re: Samsung Syncmaster T240 Backlight/InverterLeave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Ok people I am back for more!
I have found the pdf for the sem2005 16 pin chip which is attached to this post. After viewing the document I figured that there should be a min of 2.0 v on pin 11 when the monitor is turned on and a max of 1.0 V when it is off.
I have tested the chip, with the negative lead on the screw whole ground and found 3.4V when on and 0.0 V when off. Also, I found 15.57 V on the Vcc pin.
Looks like the chip is functioning, what do you guys think? I am nervous about...Last edited by Funkhauser; 11-16-2010, 02:08 PM.Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Ok, I can't refuse that offer!
U202 is 4506GEH
U201 displays: SEM2005
0817
Good luck!Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Thanks for all the help! My brain is mush from electronics all day so I will resume the testing tomorrow. Just one question, if there is a short in a mosfet, where would it be? Between the gate and the drain/source?Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Ok. Your instincts were correct.
The adj dim is 0.8V on and 0 V off.
The on/off is 4.6V on and 0V off. However, if I switch the monitor off and on with the DMM lead attached to the pin it reads 0V. I can only get the 4.6V when I switch the monitor on and then read the pin voltage.Leave a comment:
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Re: Viewsonic VE710b
Caps are a bit different than a battery in construction, you are correct. I do not think that anything could be knocked loose inside a properly functioning capacitor. However, I cannot say the same for a capacitor that is filling with gas ( the bulging effect). Considering the mess of those caps I wouldn't be surprised if replacing them will fix the problems.Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Ok. For the measurement I had the negative lead of the DMM on the test/ground.
Yes, I believe I did bridge the ground.
For the adj dim pin, it changes from 0.8v to -4.31v when switched from off to on.
For the on/off pin I got some weird values. It stays at -0.5V but when switched off to on, it jumps to 1.5 or 2.0 V then to -4.3V and then to 0V. After a few seconds it switches back to -0.5V. It was hard to determine the values as they seemed to change too fast for my crappy meter.
...Leave a comment:
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Re: Viewsonic VE710b
Well the smacking part, from what little experience I have, usually means a loose connection somewhere. This could be a solder joint or loose wire in a harness. Check the underside of the board for bad solder joints and give components a wiggle to check if they are loose.Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
I checked the pins and according to my meter there was no voltage change. Just a constant 0 V. I measured for DC and AC just to be certain.
For testing purposes I have the power supply isolated from the rest of the monitor. Will this affect anything?
Thank you for the help so far, anything is appreciated!Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
I checked from the ground to the anode and cathode of the fuse and it gave me 15 V for both and no sparks. I'm really wondering why I got sparks in the first place...Crappy meter?
I also checked the output for the CCFLs which registered 0 v (big suprise). So, the problem exists between the fuse and the outputs.Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
I used the diode function on my DMM to check for continuity of the fuse. It beeped so I was satisfied.Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
There is one transistor attached to a heatsink in the bottom left of my photo.
[URL="http://flattvparts.co.uk/index.php?main_page=product_info&cPath=5281_5283_5607_5609&products_id=8549"]This[/URL] website offers a better photo than what I can provide. It is the same board as far as I can determine.Re: Samsung Syncmaster T240 Backlight/Inverter Failure
There is one transistor attached to a heatsink in the bottom left of my photo.
[URL="http://flattvparts.co.uk/index.php?main_page=product_info&cPath=5281_5283_5607_5609&products_id=8549"]This[/URL]Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
I checked and it gave me 14.31 V and some nice sparks. To check the transistor, do I need to remove it from the board?Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Well I did not want to post any pictures because my camera is not the best but if you think it will help.
In the second photo there is what appears to be heat damage near the transformer and large R301 resistor....Leave a comment:
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Re: Samsung Syncmaster T240 Backlight/Inverter Failure
Yea I actually just checked and the fuse is working.Leave a comment:
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Samsung Syncmaster T240 Backlight/Inverter Failure
Hello,
My Samsung monitor died a few months back and not being covered under warranty I decided to try and fix it.
The Problem:
I left my room and came back to find my monitor display blank. Upon closer examination I can barely see a display and only when I view it at an angle with a light. I unplugged the monitor and plugged it back in but no change or flickering of the display. After some research I concluded that the back lights were not functioning.
I disassembled the monitor (what a horribly tedious job that was!) and inspected the...
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