Oki OKIFAX 5750 Service Manual page 904

Protection against overvoltage/overcurrent
+5Vs: The protection should be open with Fuse (F501) and shorted with D503. And sometime D202, D203 should be shorted.
+38 V: This unit's O.C.P. is drooping characteristic type. (O.C.P. TIME: MAX 10S) The protection should be shorted with Q201.
+8 V: Overcurrent protection circuit operation
-8 V: Overcurrent protection circuit operation
+24 V: Overcurrent protection circuit operation
+3.3 V: Overcurrent protection circuit operation; Auto resetting (F1 opens if this state continues for more than 10 seconds.)
(2) Block Diagram