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Old 11-01-2014, 10:21 AM   #1
Kel
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Default la2405wg 24" Monitor

I found 3 bad capcitors in this monitor and as I removed and was laying them out in order I accidentally knocked them on the ground... so does anyone know if C122 and C123 are both the 680uf 35 v. cap or is one of them a 470 uf 35w? I plan to replace all the caps, but stopped removing them after this mishap... the other cap removed was C124.

Kel
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Old 11-01-2014, 10:50 AM   #2
selldoor
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Default Re: la2405wg 24" Monitor

please update your profile with country and mains voltage,
post a good clear picture of your board using manage attachements and stte the board number and revision.
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Old 11-01-2014, 12:46 PM   #3
Kel
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Default Re: la2405wg 24" Monitor

Here's 3 pics that may help.
Attached Images
File Type: jpg la2405wg (2).JPG (231.3 KB, 36 views)
File Type: jpg PwrBD2.JPG (237.4 KB, 28 views)
File Type: jpg C122C123C124.JPG (225.7 KB, 24 views)
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Old 04-09-2015, 11:33 PM   #4
benhadad
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Default Re: la2405wg 24" Monitor

I have the same board (120v)
C123- 35v 680uf
C122- 35v 680uf
C124- 35v 470uf
C125- 35v 470uf
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Old 09-15-2018, 09:15 AM   #5
jason123
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Default Re: la2405wg 24" Monitor

I know this is an ancient post - but has the replacement of the capacitor fixed the issue? I have a similar power board - it buzzes when turns on, but only when the lower ccfl is connected. I am going through the circuit, and I don't see bad caps - ESRs are low in 60 mOhm range and no direct shorts. All resistors are close to their labeled value. Any help is appreciated. Thank you
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Old 09-15-2018, 11:59 AM   #6
R_J
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Default Re: la2405wg 24" Monitor

Does the backlight come on at all for even a second? try connecting the ccfl to the other plug, Check the resistance readings on the transformer secondaries and compair them to each other, they should be close to the same 900+ Ω
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Old 09-16-2018, 06:59 AM   #7
jason123
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Default Re: la2405wg 24" Monitor

Hi R_J,
Yes, the backlight comes on... then off.. cyclical in a sense while buzzing loud. The transformers secondary on the top transformer is 471 Ohm, the bottom is 477 Ohm

I didn't have exact size caps, so temporarily I replaced the 2 caps in the photo. Didn't make a difference.

Swapping the top / bottom CCFL cables, I can only do that one at a time. It seem, the buzzing is coming from the CCFL itself and not the board. Could the CCFL be buzzing?

One other thing to note, the on-screen menus that come up, they seem to disappear immediately. not sure if it's because both CCFLs are not fully functional?
Attached Images
File Type: jpg 20180916_053911.jpg (660.0 KB, 5 views)
File Type: jpg 20180916_053926.jpg (599.3 KB, 5 views)
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Old 09-16-2018, 07:55 AM   #8
jason123
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Default Re: la2405wg 24" Monitor

So I opened up the panel, something I was trying to avoid, and sure enough the lower CCFLs are cracked

Roughly they're 540 mm. Not sure if it's worth replacing or trashing the monitor. I see there are some CCFL out of China, but there are a lot of LED conversion kits. Has anyone used these? Is this the recommended path? Do I have to replace the 2 Upper CCFL with LED as well?
Thanks
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Old 09-17-2018, 02:04 PM   #9
momaka
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Default Re: la2405wg 24" Monitor

I think member stj has used (and recommends) the LED conversion kits, and he says they are good.
I myself don't have any experience with them. I ordered replacement a single CCFL for a monitor once out of CCFLwarehouse, and it worked fine. However, I bought a discount CCFL (to save on costs), so it came with no connectors or wires - I had to reuse the ones from the old tube. Not the prettiest job, but it worked.

That said, if you do LED conversion, yes, you DO need to replace both the top and the bottom lamps with the new LED ones. The old CCFL inverter won't work with just the top lamps connected.
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Old 09-26-2018, 07:16 AM   #10
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Default Re: la2405wg 24" Monitor

Thank you. I ordered a set of CCFLs... I'll put in the update once I get them.
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