Looking at the schematic it's got a few "5V" points where I assume they should be connected to a stable 5V line. Does that mean I should also add some circuitry to provide a regulated 5V power-supply to these points do you think?
If so I'll see if I can look up a suitable low-current regulator (don't want anything with high-current as I don't want to damage any sensative components on any set I might be working on). Infact it might be a good idea to provide two possible supplies, one being 5V and the other being 3.3V which can be switched between. The reason I say this is that some equipment now use modern microprocessors which run off 3.3V and, if I were to clip my test clip onto an NVM with 5V on it, potentially it could damage the micro or something else.