Re: Westinghouse L2410NM No Power, No LED
If you've already replaced it, it isn't necessary to replace it again unless you have a solid reason to suspect the replacement is defective.
[LIST][*][COLOR="Blue"]The solder joints look good on all of the caps and the polarity looks correct. I'll order a couple extra 100uF, 25V caps on my next Digi-Key order just to be sure though. I'm going to order a couple of the big filter caps as well since that's the only cap I haven't replaced.[/COLOR][*][COLOR="blue"]The part # on U4 is TEA15 2or3 with...
ben3843100
Member
Last Activity: 02-21-2011, 12:22 PM
Joined: 01-24-2011
Location: Northern MN
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Re: Westinghouse L2410NM No Power, No LED
Just to be clear, are you referring to the two small 22 uF 50V caps near the middle left of the board at position C22? I did initially replace all of the electrolytic caps on the board, but will replace these again if you think it's necessary. You mention the SMPS controller chip; is this the chip at position U2 on the back of the board?...Leave a comment:
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Re: Westinghouse L2410NM No Power, No LED
I've been away on businees for a bit, but have picked up this project again. In the mean time, I ordered new caps, as well as some spare fuses from DigiKey for this monitor, as well as some others I'm working on. This weekend I installed a known good power supply in this non-working monitor from one of my other working L2410NM panels and it powered on and displayed video fine, so I've now confirmed that there are no problems with the inverter or video board. I also suspected that I may have accidently blown the first 3.15...Leave a comment:
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Re: help to solve back display in 2sec
Thanks for the troubleshooting help all. I received my 4 replacement CCFLs a couple days ago and soldered them in yesterday. The monitor is working great as you can see from the pics. It probably didn't need the power supply recap, but it was good practice. In all, it cost me about $35 dollars to fix this monitor for the new caps and 4 CCFLs plus shipping. It definitely takes patience to remove and reinstall the CCFLs on this model without damaging the wiring or bulbs.
-Ben...Leave a comment:
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Re: Westinghouse L2410NM No Power, No LED
[COLOR="Blue"]I placed my multimeter on the OHMs 20k setting, placed the black lead on the source pin, and recorded the following measurements. I can remove the MOSFETs if you think it's necessary for further testing.[/COLOR]
MOSFETS:
Q2 (left)
S-D - 13.68
S-G - open
D-G - open
Reversed leads:
S-G - 7.7
Q1 (right)
S-D - 17.3
S-G - open
D-G - open
Reversed leads:
S-G - 7.7
Board Resistors: ...Last edited by ben3843100; 02-05-2011, 11:48 PM.Leave a comment:
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Re: Westinghouse L2410NM No Power, No LED
After reading up on how to test the power MOSFETS, I measured between the source pin and the gate and drain pins and received the following readings:
[LIST][*]On Q2 (left MOSFET) I received 1 for infinity between S and D, and 13.64 OHMs between S and G with my meter set at 20K.[*]On Q1 (right MOSFET) I received 1 for infinity between S and D and 17.27 OHMs between S and G with my meter set at 20K.[/LIST]
It appears that DS4, DS5, and DS7 are diodes. Should I check these out as well? I'm not sure how...Leave a comment:
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Re: Westinghouse L2410NM No Power, No LED
[LIST][*]I rechecked the bridge rectifier (I had checked it earlier) and received a 1 for infinity between each pin using the method you suggested above.
[*]Since I'm ordering fuses, do you think I should order any other components from Digi-Key at this point?[/LIST]- Re: Westinghouse L2410NM No Power, No LED
[LIST] - I rechecked the bridge rectifier (I had checked it earlier) and received a 1 for infinity between each pin using the method you suggested above.
- Since I'm ordering fuses, do you
Leave a comment:
- Re: Westinghouse L2410NM No Power, No LED
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Re: Westinghouse L2410NM No Power, No LED
I actually didn't know that. Now that you mention it, I see it says "FS1" on the board next to it. I was wondering where FS1 was, since the other fuses are labeled FS2, 3, and 4. I measured across the leads on FS1 and received a 1 for infinity on my multimeter, so that seems to be the first issue I need to resolve. It appears to be a 3.15 amp, 250V fuse. It looks to be part number 507-1181-ND on the Digi-Key site @ .45 cents each....Leave a comment:
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Re: Westinghouse L2410NM No Power, No LED
I just got home and am continuing my testing. I can take the heat sinks off if required. I just carefully bent them open when I initially installed the new capacitors.
Next steps:[LIST=1][*]Check for mains voltage (like 120V or 240V DC) at the main filter capacitor at 1.4x the line voltage. [COLOR="Blue"]With my multimeter set to Vdc and 600, I measure 5.6 volts across the leads to the large capacitor on the power supply board. [/COLOR][*]I suspect that the power supply is not starting up. [COLOR="Blue"]When...Last edited by ben3843100; 02-04-2011, 11:31 PM.Leave a comment:
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Re: Westinghouse L2410NM No Power, No LED
Here are pics of the inverter and video boards in my L2410NM. There seems to be an editing time limit or I would have added these to my initial post above. I'll post the other voltage tests later tonight. That was a small piece of foil in on the first video board picture, btw. It fell on the board when I pulled the metal cage off of the back of the LCD panel.
-Ben...Leave a comment:
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Re: New Members - please post your introductions here
Hello all,
My name is Ben and I've worked in the IT field for about 14 years. I have a graduate degree in computer science and computer information systems with a minor in management, along with a few professional certifications. I took some basic electronics classes in high school, but have always been interested in old (and new) audio equipment and electronics. I used to love trolling the garage sales for old stereo and videogame equipment and just found a sweet pong game at the local Salvation Army. I inherited a couple...Leave a comment:
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Re: Any thoughts on the $11 Radio Shack desoldering iron?
I have the Radio Shack desoldering iron as well and have found the same to be true. I have used it for a couple weeks now and it worked great on the double sided power supply PCBs I've been working on. I read in another thread that the heat output on these irons (mine is 45 watt) tends to degrade over time, but I haven't used it enough to experience this.
-Ben...Leave a comment:
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Westinghouse L2410NM No Power, No LED
I have a Westinghouse L2410NM LCD panel I'm working on. I've read through many other threads detailing similiar issues and have tried take care of the easy steps first. Here are the symptoms and troubleshooting steps I've performed so far:
L2410 LCD Monitor Troubleshooting
[LIST][*]I have no power LED and no image is visible with flashlight shining on screen.[*]When the power supply is plugged into an outlet I initially hear a faint electrical sound like the board is powering up. (capacitors charging?)[*]I do not hear a faint clicking from the power supply as described in... -
Re: help to solve back display in 2sec
Update: I found a deal on a set of 4 CCFLs for this monitor, so I ordered them and am waiting for them to come in before moving ahead. I'll let you know how it works out after they're installed. In the mean time, I'll be troubleshooting my Westinghouse L2410NM.
-Ben...Leave a comment:
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Re: help to solve back display in 2sec
It does look cracked in the picture, now that you mention it, but I took a close look at it and it and it looks like it's in one piece. I do have an AOC 15-inch LCD that I could take apart for testing. I'll take a look at it tommorrow. I'm assuming I'll need to splice in two lamps (top or bottom plugs on the inverter board) for testing to complete the circuit. Thanks for the help.
-Ben...Leave a comment:
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Re: help to solve back display in 2sec
I dissasembled the screen down the the CCFLs, compared them to the pictures in the above links, and read through the threads describing the inverter circuitry and how it has a built-in protection circuit that shuts down power to the lamps if there is a lamp problem. The lamps in the attached pic do seem dark on the ends. What do you think? New lamps?
Looks like these are two recommended links from other threads.
[url]http://ccflwarehouse.com/blandovsp.html[/url]
[url]http://ccfldirect.com/blowou...Leave a comment:
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Re: help to solve back display in 2sec
According to the measurements below, they seem to be reading within 3% of each other.
Yellow Dot Measurement: .609
Red Dot Measurement: .598
I reassembled the boards and plugged the LCD into a PC. I see my designated wallpaper for about 1-2 seconds, then nothing. I used a bright LED flashlight to look at the screen from multiple angles and didn't see a thing after the screen went dark. I did notice, however, that when you unplug the VGA cable with the power to the LCD on, the unit...Leave a comment:
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Re: help to solve back display in 2sec
The capacitors used to repair the power board were a combination of Nichicon and Rubycon. Pictures of the inverter / power board are below.
Now that I've taken a second look at the video board, I see the capacitors on it are Samxon and Su'scon. Perhaps these require replacement as well....Last edited by ben3843100; 01-31-2011, 07:39 PM.Leave a comment:
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Re: help to solve back display in 2sec
I guess it's up to me to resurrect this threat. I have a Samsung 920nw in my possession with the same problem as the original poster; the display turns on fine and displays the input signal for about 1-2 seconds, then the display goes "black." The power LED stays on when the display blanks out. My first thought was to replace the capacitors on the combination power / inverter board. I ordered and just completed replacing all of the capacitors on this board.
The display problem has not changed. It still blanks out after...Leave a comment:
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Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers
If you have a Radio Shack near you (or online), they have a nice 45 watt de-soldering iron for only $10.99. I'm no pro, but I picked one up and it was very easy to remove the caps on my LCD power supply board with the special tip and suction bulb. I haven't tried the following, but you may be able to swap the tip for a standard soldering tip available from Radio Shack and use it as a regular soldering iron as well.
[url]http://www.radioshack.com/product/index.jsp?productId=2062731[/url]...Leave a comment:
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