I have an HP w2408 LCD that makes a constant buzzing noise when the brightness is less than 100%. If I turn the brightness all the way up to 100%, the buzzing stops. It has been making this noise for years, I've just now decided to try to do something about it! Except for the buzzing, the monitor works great.
I'm not sure if the issue is with something on the inverter board or the CCFL tubes themselves. I've been searching the forums, but haven't found another post that has a solution to this issue (yet).
I've disassembled the unit, but I can't seem to isolate the buzzing to a single component. The buzzing starts immediately when the CCFLs light up after I power on the device. I've tried poking at each of the inverters with a plastic stick to see if the noise might change when some pressure was applied - it didn't. None of the inverters are showing any signs that they have been overheating.
The capacitors appear ok - no bulging, burning or leaking of electrolyte.
I tried disconnecting one of the CCFL tubes. When I do this, and power the unit on, the remaining CCFLs light up for about a second (without any buzzing!), but then the monitor shuts down about 1 second after that. I'm assuming this is because of some fault protection circuitry. It doesn't seem to matter which of the 6 CCFLs I disconnect - I get the same result - no buzzing, but the monitor shuts down after 1 second.
I've attached a few photos for reference - the model number on the inverter board is QLI-002. A yellow sticker on the board has the numbers: 790111420000R S1100BA00NY33 0728
Any suggestions on the procedure to troubleshoot this? I'll keep searching the forum to see if I can find anything...
Thanks!
-Fritz
I'm not sure if the issue is with something on the inverter board or the CCFL tubes themselves. I've been searching the forums, but haven't found another post that has a solution to this issue (yet).
I've disassembled the unit, but I can't seem to isolate the buzzing to a single component. The buzzing starts immediately when the CCFLs light up after I power on the device. I've tried poking at each of the inverters with a plastic stick to see if the noise might change when some pressure was applied - it didn't. None of the inverters are showing any signs that they have been overheating.
The capacitors appear ok - no bulging, burning or leaking of electrolyte.
I tried disconnecting one of the CCFL tubes. When I do this, and power the unit on, the remaining CCFLs light up for about a second (without any buzzing!), but then the monitor shuts down about 1 second after that. I'm assuming this is because of some fault protection circuitry. It doesn't seem to matter which of the 6 CCFLs I disconnect - I get the same result - no buzzing, but the monitor shuts down after 1 second.
I've attached a few photos for reference - the model number on the inverter board is QLI-002. A yellow sticker on the board has the numbers: 790111420000R S1100BA00NY33 0728
Any suggestions on the procedure to troubleshoot this? I'll keep searching the forum to see if I can find anything...
Thanks!
-Fritz
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