Color Classic buzzing from CRT

[DW1992]

Hi Everyone,

I recently recapped the analog boards in my two Colour Classics.
One is a Mystic, the other is a stock CC.
Their logic boards were recapped months ago.

Both worked perfectly after their recaps, and the Mystic still does. However, the stock CC analog board has started emitting a buzzing sound when the CRT is powered up.
I'm nearly positive its not the fly back itself, as the noise seems to be coming from closer to the front of the machine, or perhaps the coils on the tube?

The machine still works, with a perfect picture on the screen. It jut emits this buzzing noise that ebbs up and down (hard to explain, recording below).

Here's an MP3 I made. You can hear the boot chime, then the screen powering up and the buzzing starting.
https://www.dsbbs.ca/tx/CC_Buzz_MP3.mp3

I've double checked that all the replaced capacitors are the correct values and their polarities are correct.
The Mystic's analog board (came replacement components) has no noise issue.

Any hints or suggestions greatly appreciated!
Aaron/DW
Dark Systems BBS

 

[slaanesh]

Hi I have a Macintosh colour classic and have also recently recapped the analog board and also have a funny buzzing/screeching noise coming from my CRT and flyback area but it’s really hard to determine exactly where it’s coming from.
They display on mine is also perfect and everything else seems to work as it should except for the noise.
I didn’t recap the entire analog board only the recommended power supply capacitors.