TRS80 Model 100 technical questions

According to the schematic in the printed Technical Manual, the connector is centre -ve. The mains adapter replaces (electrically) the 4 internal AA cells when it's connected (there's a switch in the input conenctor that disconnects the internal battery +ve terminal when you put the adapter plug in). Therefore, the adapter doesn't need to be well regulated (since the batteries aren't). There's a fairly complex DC-DC converter on the main PCB to produce +5V and -5V from the batteries, and that provides regulation too. I think the official mains adapter (at least the one sold in the UK) was just a transformer, rectifier and smoothing capacitor. However, I'd not want to apply a voltage wildly different from 6V to the machine. It will probably be OK, but I don't fancy rebuilding that DC-DC converter if it's not :-) -tony