GULP!!
have to say that I have forgotten about any sort of PTU on the classic 747. Then again I did do the engineering course back in 1994 which was not yesterday!!!
However regards to the B744, yes as Rainbow said the AC pumps on systems 2 and 3 are options. If you look at MAS B744's (basic configuration) they have 4 ADP's across the ship. Took me by surprise first time I saw it as I had done the BA differences course from the classic.
Hope that this helps.
Flying Spanner
