The SE and SE/30 have a separate power supply box. In other words, the SE-series is unlike the Mac 128k to Mac Plus -- early machines which had the power supply components built into the analog board on the side of the machine. Hence, you can change out the power supply (PSU) in SE-series machines without changing out the analog board.
So why did I not do just change out the PSU? The reason is because you have to not only find a PSU that is small enough, but also one that would supply more power than the original while at the same time remain cool, and find one that has an ISOLATED set of two +12v outputs. The need for two isolated 12v lines is because you need one 12v line for the drive and the other for SWEEP (CRT). If you use a PSU with only one 12v (as most are), then noise could possible creep onto the CRT display. I don't want the potential for more noise in my machine, so I have been searching for a compact PSU with two separate +12 outputs (along with 5v and -12v outputs) that would be ideal for the SE/30. I have yet to find one like this.
It is therefore easier to add a second PSU as I did to offload the biggest load on the machine -- a big hard disk. Of course, if you buy an external HD case, you could accomplish the same -- albeit with a slightly bigger footprint overall for the system (relative to everything being in the same box).
So why did I not do just change out the PSU? The reason is because you have to not only find a PSU that is small enough, but also one that would supply more power than the original while at the same time remain cool, and find one that has an ISOLATED set of two +12v outputs. The need for two isolated 12v lines is because you need one 12v line for the drive and the other for SWEEP (CRT). If you use a PSU with only one 12v (as most are), then noise could possible creep onto the CRT display. I don't want the potential for more noise in my machine, so I have been searching for a compact PSU with two separate +12 outputs (along with 5v and -12v outputs) that would be ideal for the SE/30. I have yet to find one like this.
It is therefore easier to add a second PSU as I did to offload the biggest load on the machine -- a big hard disk. Of course, if you buy an external HD case, you could accomplish the same -- albeit with a slightly bigger footprint overall for the system (relative to everything being in the same box).