[MRCA] Dyno Starts Trip Breaker on PP-7333

[Doran Platt]

OK.... I'm re-acquainting myself to the PP-7333/GRC supply.  The voltage
adjust pot is R-29 on the schematic and on the board, just above R-28 on 
the regulator board.  Its the blue trimpot in the lower, center of the 
board.   Note also that the 28v supply is floating above chassis ground. 
  Ground comes out Pin B of the output connector.  I wish I could find a 
book on this thing but nobody seems to have come across one.  I was 
informed that all those extra pin connections on J1 of the regulator 
board were for the ATE (automatic test system).  That would appear to be 
correct.  Also, note that +28v goes to ground on the regulator board and 
-28v is high.  Looks like one would have to be a bit careful 
troubleshooting this thing, in the case.  Found out that the control 
rectifiers can carry 100 amps RMS and 70 amps avg. continuous.  Looks 
like some of our gear might push this rating?  The rating of the power 
xformer appears to be 85 amps if the DLSA lookup was correct.  Dunno.... 
maybe this thing is, in fact, a 60 amp supply with a 30% safety factor. 
  I could not cross or find/look-up the series choke specs.  So much for 
the old "100%" factor for military stuff....hi!  Although the  CAGE code 
on the units show that the mfgr was Naval Air Warfare Center, 
Indianapolis, IN., I also found a ref for some obscure electronics mfgr. 
  Maybe they did the follow-on.   The NSN for the PP-7333 is 
6130-01-048-9920 for those interested.  The USMC TO&E shows this 
equipment related to an integrated commercial land-line and field 
telephone system.  The "task" associated with the PP-7333 is related to 
this activity, rather than the radio side of the house or so it reads. 
I did note, though, that the supply is listed with the /GRC nomenclature 
which would indicate to me that it is/was associated with radio 
equipment.  Further, this supply was replaced with a later unit with a 
"UIQ" designator and refers to some PA and telephone equipment.   But 
enough of this.... is anyone interested, anyway?  de Jeep/K3HVG