Author Topic: CTM 644 making noise only heard by a young one  (Read 233 times)

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Offline genesis8

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CTM 644 making noise only heard by a young one
« on: 20:52, 19 November 18 »
My mini me (15 years old) complained about a very disturbing noise that I couldnt hear.


The only thing which had changed in the room is my Amstrad CPC monitor CTM 644 which was ON even if no CPC linked on it. Forgot to switch it off after removing a CPC with a video problem.


The noise stopped at once as I removed the power line.


So my old ears cant hear some frequence he can, could it be a possible safety problem like a risk of fire ? Or safe but just not for his ears ?


If it is safe, then I just discovered the best invention of the century to be able to play (Amstrad CPC/PC) games without any interruption ! Woot.
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Offline ComSoft6128

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Re: CTM 644 making noise only heard by a young one
« Reply #1 on: 21:07, 19 November 18 »
Sounds like you have ( Pun intended ) the CPC version of this:

https://en.wikipedia.org/wiki/The_Mosquito

 :D


« Last Edit: 21:10, 19 November 18 by ComSoft6128 »

Offline genesis8

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Re: CTM 644 making noise only heard by a young one
« Reply #2 on: 21:12, 19 November 18 »
Sounds like you have ( Pun intended ) the CPC version of this:

https://en.wikipedia.org/wiki/The_Mosquito

 :D


I was thinking about this type of device, but the monitor has no speaker, so an electronic component does this noise and I would prefer to know if it is a possible hazard.
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Offline ComSoft6128

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Re: CTM 644 making noise only heard by a young one
« Reply #3 on: 21:18, 19 November 18 »
Probably best not to use it until one of the hardware guys gets back to you with their assessment.




Offline Bryce

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Re: CTM 644 making noise only heard by a young one
« Reply #4 on: 09:44, 20 November 18 »
It's called "CRT Whine" and it's quite common for old monitors. It comes from the flyback transformer windings becoming loose and vibrating at the around 15kHz. The monitor isn't broken and may last for many years yet. The reason your son can hear it and you can't is due to Presbycusis (age related insensitivity to certain frequencies) which we all get at some stage.

Bryce.

Offline pelrun

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Re: CTM 644 making noise only heard by a young one
« Reply #5 on: 11:36, 20 November 18 »
Modern kids don't know what they're missing!

I remember always being able to tell if a TV was on by ear, even if there was no picture or sound.

Was less funny when the school computer lab had a bad monitor that squealed painfully loudly and none of the staff could hear it, so they wouldn't send it off for repair or let us turn it off.

I'm at the point where I can't hear it now, so it doesn't matter to me if my CTM644 is doing it :D


Offline Audronic

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Re: CTM 644 making noise only heard by a young one
« Reply #6 on: 14:00, 20 November 18 »
[quote  I'm at the point where I can't hear it now, so it doesn't matter to me if my CTM644 is doing it :D

Ditto

Ray
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