UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Copicat MK2

Uncle Bulgaria · 24th Mar 2019, 2:47 am

If you're touching something and there's a change, then that means there's a misconnection somewhere. Similar to touching the grid of a powered valve with a probe.

In my limited troubleshooting expertise, I would check the resistances of all marked ground connections, and the links between signal ground and PSU ground - if you've changed the earlier grounding scheme (live/neutral to live/earth/neutral) then you could have upset the balance of signal grounds between your equipment. If you aren't sure where the current is flowing between your components, have a check. The shields between units shouldn't be providing a better path to ground than the circuit!

24th Mar 2019, 2:47 am	#39
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,335	Re: Copicat MK2 - No Echo If you're touching something and there's a change, then that means there's a misconnection somewhere. Similar to touching the grid of a powered valve with a probe. In my limited troubleshooting expertise, I would check the resistances of all marked ground connections, and the links between signal ground and PSU ground - if you've changed the earlier grounding scheme (live/neutral to live/earth/neutral) then you could have upset the balance of signal grounds between your equipment. If you aren't sure where the current is flowing between your components, have a check. The shields between units shouldn't be providing a better path to ground than the circuit!