So I bought a transformer to replace a dead one in an old game console and I've some issues. I wasn't able to get an exact replacement but found one only about 10% out of spec. What I was replacing was a transformer that put out 18v and a separate 18.5v with a center tap (2*9.25v) on the secondary side. What I was able to order from this one place was a transformer with a 20v feed and a center tap (2*10v). When I received it I found it was 20% beyond what it was rated for (12v on the 10v secondary, 24v on the 20v secondary). I got the company to send me a replacement and it too was labeled as a 20v/10v but outputs 24v/12v instead. But I wired it up instead to see if it was close enough. I wired the transformer to the power circuit board and separated the power circuit board from the rest of the system. That way if something blows it only takes out the power reg circuitry and I've already got a contingency if that happens. I then tested the outgoing DC voltages from the circuit board and the were within spec so I suspect the 24v-18v difference is not too much to cause problems nor is the 12v-9.25v difference. It seems like there isn't a problem but the one thing that concerns me is that the transformer get hot. VERY HOT! It's only been powered up for a few minutes at a time and it's making a bit of noise as the insulating tape wrapped around it heats up and melts to it. Also the transformer vibrates when it's plugged into the circuit board and the transformer is plugged into the wall, regardless of whether or not the system is powered on! So not withstanding the voltage differences I think I have one other concern but I'm not if it's the reason for the heat. The original transformer had one secondary line at 18v and then a second, separate secondary line at 18.5v with a center tap. The replacement has two secondary lines that can be bridged to make a single with double voltage, in other words basically a center tap. But I'm running the lines expecting the separate 18v and 18.5v(ct) off of only one secondary winding set. If my descriptions aren't clear enough, I've attached a paint image to make things worse. So tell me what you all think, is it the difference in layout of secondary windings generating the heat? Differing voltages? Bad transformer?