On 03/24/2026 1:56 PM EDT Aidan Riley via GreenKeys <[email protected]> wrote:

 

 

Good afternoon all, 

 

I appreciate the advice from Doug and Wayne to replace the electrolytic capacitor in the local loop supply. This fixed the loud "buzz" when the machine was plugged in. However, my local loop supply still seems to be having issues. Signals on the "Line" side seem to work fine. I also had to reconnect R7 on the vertical board, as its connections had some loose.

 

Good afternoon all, 

 

I found that the 1/2 amp slow-blow fuse had gone out. Eureka, I've found the problem and everything will be fixed! I replaced it, and now the dreaded buzz has returned. 

 

I'm not sure where to go from here, looking for further suggestions. I've attached a scope capture taken across the terminals of the new capacitor in circuit. Probe 1 is on the + side of the cap, Probe 2 on the - side, Red line is the difference between them. All should be scaled the same. 

 

thanks and 73, 

Aidan W9POG

 

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