Hello BXJ,
Sorry, no diagram handy, but I can tell you the pnuematic ports are located:
752:
~20M aft of Nose
.6M left of Centerline
.9M right of Centerline
753:
23M aft of Nose
.6M left of Centerline
.6M right of Centerline
This puts the fuselage inlet ports just about abeam the midpoint of the nacelles. 3 Ports for the RB211s - 2L 1R - while the Pratts have 2 ports - one on each side.
Minimum pressure and volume is around 40PSI at 200-250 lbs/min @the connector (or 35PSI cockpit duct press gauge) depending on outlet temp. All of the 37s have the ASU less than 2M from #2 while on the 57s the distance is more like 5M.
THere seems to be no such problem with the 757 or indeed any kind of schematic in any of the 'new and improved' (or rather thin) Boeing tech manuals regarding the actual position of the ASU connection points on the aircraft belly.
I couldn't agree more - the old Boeing materials were indeed more in depth. Of course there were more gauges, fewer all-knowing computers, so I guess a deeper understanding of the machinery was a necessity.
cheers !
vapilot