There should be plenty of grounds in the ribbon cable for the floppy interface (unless you are plugging/unplugging with the power on, not recommended in this multi-powered setup).
However, a likely cause of trouble is back-powering the BBC from the Gotek when the BBC is nominally powered off - pull-up resistors on drive interface signals at the Gotek end, supplying power through the protection diodes of chips at the BBC end and into the BBC power rails.
This can at best lead to power-on-reset circuits failing to work, and at worst lead to latchup within chips (which then get extremely hot and risk damage).
So either stop doing this, or try it again and (after powering up the BBC and getting no sound) check for any hot chips in the sound area.
However, a likely cause of trouble is back-powering the BBC from the Gotek when the BBC is nominally powered off - pull-up resistors on drive interface signals at the Gotek end, supplying power through the protection diodes of chips at the BBC end and into the BBC power rails.
This can at best lead to power-on-reset circuits failing to work, and at worst lead to latchup within chips (which then get extremely hot and risk damage).
So either stop doing this, or try it again and (after powering up the BBC and getting no sound) check for any hot chips in the sound area.
Statistics: Posted by arg — Mon Jan 01, 2024 10:13 pm