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Hitch pitch noise from monitor

By fear_the_tweenies ·

There's a high pitch noise coming from my Compaq Presario 3150UK's monitor after it's been switched on for a short period of time. This doesn't happen as soon as the machine is booted, it's fine at this point. Anyone any ideas as to what could be causing this noise? Any suggestions would be greatly appreciated.


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by jschein In reply to Hitch pitch noise from mo ...

Right click desktop settings, goto properties...

You want to get into the video card properties to the refresh rate. Lower it, test, if it works, save and adjust display. This pre-emptively happens when a monitor is close to it's time.

However, If you just lower the refresh rate, it should last you another year or so and not whine any longer.

Good luck

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by fear_the_tweenies In reply to Hitch pitch noise from mo ...


Thanks for the reply. Problem is, I've only had the monitor/PC for a few months! Not only that, but I've hardly used it too! My display is configured with the recommended refresh rate, so I don't think it's anything to do with that.

Thank you for your input!

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by csmith In reply to Hitch pitch noise from mo ...

The whine is the high voltage power supply.
The main PS provides DC (Direct current).
That's great for most of the circuits, but the voltage is not high enough for the sweep and anode.
so an oscillator is used to create a high frequency AC (The Noise) this AC is transformed and rectified to the necessary voltages.
Fortunatly all this nonsense goes away in the flat panel displays. (To be replaced with other problems)
Changing the refresh rate is a simple way to change the load on the oscillator, and thus trouble shoot it.

This sounds like shipping damage.

If a repair tech inspects the monitor, he may find obvious damage to the High Voltage Section, or a damaged/misset potentiometer.

I would recommend that your local monitor repair shop check this monitor for you.
Regards, Chris

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by TheChas In reply to Hitch pitch noise from mo ...

Chris has it right.

All CRT style displays have a high frequency high voltage power supply.
For US televisions, the frequency if 15,750 hertz.

The monitor will use near the same frequency for the horizontal sweep.

It may or may not be shipping damage, and may not even be covered by your warranty.
What most likely has happened, is that the adhesive used to secure the windings on the 'fly-back' transformer has failed and is allowing the transformer to vibrate.

Your monitor can run for years like this, or fail tomorrow.

You should at least contact HP/Compaq to see about a warranty return / repair.


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by pctech In reply to Hitch pitch noise from mo ...

I agree with Chas that it is the flyback transformer. The chances are good that it will fail prematurely. Check your warranty.

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by yelhsa3840 In reply to Hitch pitch noise from mo ...

I repair monitors and electronics for a living and
your eventually gonna lose the monitor and your lookin around 100$$ to fix it or up i have also seen monitors do this for over a year, eventually the high pitch will cause your upper hearing to get bad and it will go away, like machinists

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