The problem is not pluggin the mouse or joystick in, but shorting accross the port pins with the metal surround of the mouse plug. If any of the pins are shorted against pin 7 (+5v) you risk damaging your miggy.
Actually this is very difficult to do because the metal surround is recessed quite some way from the front edge of the mouse plug.
I have plugged in Joysticks and Mouses directly into my powered on Amigas for 20 years. I have never had an amiga die. Just luck or care ?
BTW: If you put your pinky on the metal pin of a live AC plug when you insert it into a AC socket you could seriously damage your heart muscles and/or kill yourself. Rare but it can happen. You need to afford your miggy the same care.
When plugging into the serial, diskdrive and monitor ports you really should power off your miggy as these ports have 12v on them. But as the manual says to be safe always power off before plugging and unplugging items.
On the original problem, I liked the sound of the power supply being the issue but the fact that the problem still occurs with the accel removed points to the Roms or a deeper problem. Having 2 miggys makes it easier to knock our pwr supply issues. Have a look here and see if any of this fits:
http://www.amigahistory.co.uk/selftest.htmlBTW. I have always used my std black A1200 power supply on my 030 33 cobra / 6Gb drive A1200. No probs. knock on wood.
:rtfm:
