[Test-Equipment] Need schematic/ideas for Pyramid Phase III PS12 Supply

[Doug Hensley]

I have a Pyramid Phase III 13.6V DC power supply called the PS12.  Marked as a 12 Amp supply and seems to an early Tenna unit.
I need a schematic for it.  The issue I am having is that while it puts up the rated voltage, at turn off it does not bleed down quickly but slowly discharges down as if the caps are bleeding down.  The front panel LED for example stays on a long time and watching my Fluke, the voltage very slowly drops taking maybe 20 seconds or so to get down past 3V. I'm used to a 12V supply going to zero fairly quickly.  Any suggestions on what to look for?  I'm poking around it now with my Fluke VOM and a couple of digital cap testers.  
Doug