Strange skreaking or humming sound

[Redreamer82]

My Jag makes a strange almost "skreaking like" sound. It is not verry loud but I hear it when I am 1,5meter from the system. The frequency of the sound changes depending on workload or perhaps due to screen update. Should I start thinking about changing the Caps?

[Zerosquare]

This is a known thing that occurs on some Jaguars, it's not a symptom of a problem.

Quote

Q. Hey! My Jaguar makes a quiet hissing sound! What's going on? Is it dangerous?

 

A. Early Atari Jaguars had a rumored problem with the console hissing softly. Atari had cited several reasons for the hissing noise. Some have said that the sound is from the RF generator. The RF shield has holes in it (ostensibly to help air flow and keep the unit cool), and it is believed that the holes produce the noise. Others said the sounds are produced by coil L29 which is responsible for the proper voltage regulation to +10.0V, together with U38. The coil's copper wire vibrates when the current through it changes abruptly, making the hiss.

 

There are two solutions:

1) Use plastic spray or silicone rubber glue to fix the coil's wire.

2) Replace the original Jaguar power-supply with a variable power-source, using 7.5V DC instead of 9V DC (it is not certain whether the Jaguar CD will require 9V DC, which would make this "fix" unworkable with the CD drive).

 

In any case, the "hissing" noise was not dangerous, but merely annoying. It was usually audible only if you put your ear next to the unit and listen closely, and is not interference in the audio output. It is roughly analogous to the buzz made by electric clocks. Most later Jaguars did not have this problem, though a few rare cases have been noted.

 

Edited October 17, 2020 by Zerosquare

[Redreamer82]

Ok. Super. Thanks for the info. Tried to google it but didnt find this explanation to the issue.

[+Stephen]

BITD, we called it the "kitty's purr".

[eightbit]

I had a few units in the past that did this. It is coil whine...which still occurs today. I work for a video card manufacturer and when the Geforce GTX 900 series came out they all experienced pretty much the same thing. We received a lot of calls about it but we were all instructed to say that this was "normal" and is not considered a warranty related issue/problem

[Keatah]

That sound in my head all the time won't go away!