We were running our Dyna 2400 fine for 3 days making parts and then went to change the part after it was waiting for ~5 minutes. It just started buzzing from the Spindle controller board (?). Did a search here and found someone with a similar problem but with a Gecko conversion, but no responses and this one is stock. Everything was running fine for years.

Does anyone have a clue what the problem is?

Thanks Jon