Help needed with sudden 120Hz hum in Mission Amps 5e3

[rdh006]

I wanted to wrap this thread up, post the final solution, and say thanks to everyone who helped.

Being outside the USA, a simple thing like getting a replacement tip for my soldering iron took a while in the holiday period.

I got the soldering gear working again today. Following Chuck H's logical walk-through above, I rewired all the ground connections in the power supply. I had a collection of ground tags at a transformer bolt, so I took those out and put in a tag strip with the tags laced together so that I could remake the connections and see them better. In moving those ground wires, one didn't feel right -- the other end was loose. So I had a filter cap ground that looked OK visually and metered OK, but the connection was loose internally. Put it all back together and the hum has gone.

So thanks, guys, for the great input, I learned a lot and finally got a good result.

[Tone Meister]

Very good thread. This is the way to get help. Your level headed responses and uncanny ability to track all the information and clearly communicate each detail was the key here, rdh006.

This is one of the best threads I've seen here. Kudos.

[rdh006]

Thanks for the kind words, Tone Meister. I'm just pleased to get a resolution. I have a gig tonight and I can use my favorite amp again. This forum is a great resource.