Print Page - CTM 644 making noise only heard by a young one

Title: CTM 644 making noise only heard by a young one
Post by: genesis8 on 19:52, 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.

Title: Re: CTM 644 making noise only heard by a young one
Post by: ComSoft6128 on 20:07, 19 November 18

Sounds like you have ( Pun intended ) the CPC version of this:

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

:D

Title: Re: CTM 644 making noise only heard by a young one
Post by: genesis8 on 20:12, 19 November 18

Quote from: ComSoft6128 on 20:07, 19 November 18
Sounds like you have ( Pun intended ) the CPC version of this:

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

Title: Re: CTM 644 making noise only heard by a young one
Post by: ComSoft6128 on 20:18, 19 November 18

Probably best not to use it until one of the hardware guys gets back to you with their assessment.

Title: Re: CTM 644 making noise only heard by a young one
Post by: Bryce on 08:44, 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.

Title: Re: CTM 644 making noise only heard by a young one
Post by: pelrun on 10:36, 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

Title: Re: CTM 644 making noise only heard by a young one
Post by: Audronic on 13:00, 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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General Category => Amstrad CPC hardware => Topic started by: genesis8 on 19:52, 19 November 18