I bought a used Mac mini A1176 a few years ago (originally using the A1188 model, 110W power supply), and these days I found an used A1105 (85W). Unfortunately both (mac mini and power) didn't work together, there is no sign of life, but honestly I'm not sure if the Mac mini is working, as I've never tested it before. I'm an electrician, so I tested the A1105 power supply with a multimeter on all internal pins, and only 2 of their pins (out of a total of 5) showed 18.5V. I believe the tension pins were created in different locations for each model.