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Computer Monitor Whining and Humming


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#1 ttcole1254

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Posted 25 November 2012 - 08:43 PM

I have a Dell Genesis computer monitor from '01 to '03. Anyway, lately it's been making this whining sound from the panel itself, and it seems to be more high-frequency when there is more white on the screen, and almost gone when there is more black on the screen. More recently, it started shoving that frequency across anything connected to it, even my computer speakers. My speakers now have a sound like when there's an audio short. A low-frequency hum. Again, it changes frequency to what's being displayed.

I think it could be the power supply, being about 9 to 11 years old or so. I took apart the monitor, and the squealing is coming directly from the Genesis processing chip. The chip says simply Dell Genesis on it, so I'm assuming that's what it does.

If anyone knows if there's a way to fix this, please let me know. I have a newer Acer monitor that sits next to this one, and it runs perfectly normal.

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#2 rotor123

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Posted 25 November 2012 - 09:36 PM

Hi

Since that is the case, I would look at the capacitors and see if any are bulging or leaking. http://www.badcaps.net has examples of bad capacitors on the right side of their home page. I would look carefully at the Power Supply board.

Good Luck
Roger

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#3 ttcole1254

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Posted 25 November 2012 - 11:18 PM

I was thinking bad caps, however the power circuitry for this monitor is actually inside a power brick. I thought that was kind of odd considering most today have the circuitry behind the panel instead. I might try replacing the brick, or test the other caps on the main board. In the past week I've replaced 13 bad caps on a computer motherboard, three on my television, and two on a video card. I don't have much luck with caps I guess haha.

#4 rotor123

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Posted 26 November 2012 - 09:28 AM

Hi

At least you had the good luck to recognize the problem and the skills to alleviate the problem.
Just in case you didn't know all capacitors do not bulge or leak when they go bad.

In this case I suspect that I would go to the badcaps forum for Troubleshooting Computer Displays

Technical discussions covering any type of PC/computer display, whether it be CRT, LCD, or anything else. When starting a new thread, please be VERY descriptive of your issue, that way you'll get the best answer possible!

And post your problem.

Good Luck
Roger

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#5 ttcole1254

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Posted 26 November 2012 - 09:47 PM

Yeah luckily.. Replacing that stuff would cost a pretty penny. I actually just received a capacitor tester online I bought from eBay, and I know I have to remove them from the circuit before I check. Just as a test, I tried the ones I took out, and the ones I put into my television, and the bad ones read 200 uF, while the replacements read 1200 uF! Both were rated for 1000, so no wonder it didn't even start. I'll take a look at that forum. I knew they existed, but I had no clue they had a monitor section. Thanks for the info! :)

#6 rotor123

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Posted 27 November 2012 - 09:15 AM

Good Luck

I'll be interested to hear how this works out for you.

Roger

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#7 ttcole1254

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Posted 06 August 2013 - 04:14 PM

Well it recently started flickering when a lot of white was being displayed, so I attempted to reflow the processor chip using a heat gun and some flux. It stopped flickering, but is still whining just as it did.

 

I'm probably just gonna end up buying a new display anyway.. the resolution isn't so high and it's very large compared to the newer ones.

 

I think the power supply may even be going bad since I measured it and shows a few volts under what its supposed to be.

 

Tyler


Edited by ttcole1254, 06 August 2013 - 04:14 PM.


#8 Chris Cosgrove

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Posted 17 August 2013 - 07:40 PM

If you measured your power brick and the output was below the rated voltage it is definitely on the way out. I have no idea what it is rated at but let's say it is rated at 25V and 3A output ( = 75W ). The 25V is when it is plugged into the monitor and driving it. So, if you measure it out of the monitor, across the ends of the leads, you should get a voltage higher than 25V - anywhere from 25.5 to 27.5V depending on how well made it is.

 

Production tolerances on electrolytic capacitors are wider than on any other electronic component I can think of, +/-25% of rated value is normal for standard range electrolytics - which is why you don't use them in timing circuits unless you have to - but a 1000uF capacitor that measures at 200uF is well and truly goosed.

 

I an inclined to agree with you that it is time for replacement, you will probably be well impressed with the colour rendition of a good quality modern monitor.

 

Chris Cosgrove






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