Annoying hitch pitch noise on M4GA

[John(Wales-UK)]

Hey all

One of my Model IV machines has developed an annoying high pitch noise at certain points during operation.

1. Power up to FreHD boot screen - no noise.
2. Boot operating system - noise starts.
3. Hold down break key - noise stops.
4. Press other keys e.g. space - pitch of noise lowers.

Your thoughts on the matter would be appreciated.

Kind regards

John

 

[John(Wales-UK)]

Well we seem to have drawn a blank here guys. I suspect the power supply but there again, the high pitch noise could be my wife telling me to "stop playing with those old computers..."

 

[rittwage]

High pitch noise is of course something vibrating quickly. Most likely is a coil somewhere, and usually they are dampened by a bit of glue. I would check the monitor board or power supply for them.

 

[John(Wales-UK)]

I finally replaced the power supply with one of the later 230 / 110v supplies that I removed from an external hard drive. Three rifa caps and a few dry joints later, all good.

 

[Dr_Diesel]

I had exactly the same problem with my M4GA and Astec PSU. It turned out to be dry solder joints on the PSU flyback transformer that caused the noise.