A CRJ700 ON DSCNT AT FL200 DECLARED AN EMER DUE TO CAUTION MESSAGES ON FLT SPOILERS AND SPOILERON. CLRED BY MAINT BY POWERING DOWN. NEXT FLT; GOT SAME MESSAGES WITH A QUICK SHORT ACFT ROLL.

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THIS RPT ACTUALLY REFERENCES 2 FLTS. AFTER A PROBLEM WITH FLT SPOILERS AND SPOILERON CAUTION MESSAGES WHILE DSNDING INTO ZZZ1; WE EXECUTED QRH PROCS; DECLARED A PRECAUTIONARY EMER; AND LANDED UNEVENTFULLY. MAINT WAS CALLED IMMEDIATELY AND AFTER 2 HOURS; THE PROB WAS NOT FIXED. THE MECHANIC WORKING ON THE PLANE IN ZZZ1; IN CONJUNCTION WITH MAINT CTL; SUGGESTED WE SHUT DOWN THE PLANE COMPLETELY FOR 5 MINUTES AND RESTART IT TO SEE IF THE PROB WOULD GO AWAY. I TOLD HIM THAT IF THAT IS THE PROC AND IF IT FIXES OUR PROB; I WOULD FLY THE PLANE. IT WORKED; AND ON THE WAY OUT TO THE RWY; AS AN ADDITIONAL CHK; WE RAN A COMPLETE FLT CTL CHK. EVERYTHING OPS CHKED NORMAL. ON DSCNT INTO ZZZ2; ON THE RETURN FLT; WE AGAIN GOT IB AND OB FLT SPOILERS AND IB AND OB SPOILERON CAUTION MESSAGE; ACCOMPANIED BY A QUICK SHORT ROLL WHICH WAS EASILY COUNTER CTLED. QRH PROC WAS FOLLOWED; EMER DECLARED; DISPATCH CONSULTED; LANDED WITHOUT INCIDENT. I HAVE SERIOUS RESERVATIONS ABOUT SHUTTING DOWN THE PLANE AND RESTARTING IT (HARD REBOOT) IN ORDER TO CLR MAINT DISCREPANCIES. THE FIRST MAINT FAULT INDICATED A 'POWER CONTROL UNIT RUNAWAY' WHICH IS POTENTIALLY PRETTY SERIOUS. WHEN WE LANDED IN ZZZ2; MAINT FAULT INDICATED SEVERAL 'POWER CONTROL UNIT JAMMED' CONDITIONS. IN ZZZ2; THE MECHANIC HAD INITIALLY INDICATED THAT HE COULD NOT CLR 2 SPOILER CTL COMPUTER MESSAGES. I DON'T THINK OUR ORIGINAL PROB WAS FIXED. IT WAS PROBABLY ONLY MASKED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CAPT BELIEVES THE REAL PROB IS MASKED BY THE POWERING DOWN OF THE PLANE; AND WAITING 5 MINUTES OR LONGER AND THEN REPOWERING THE PLANE. THE TECHNICIAN WORKED FOR TWO HOURS SELF-TESTING UNITS AND SWAPPING UNITS WITH NO ELIMINATION OF THE SPOILER AND SPOILERON CAUTION WARNING. AT TERMINATION OF THE SECOND FLT; MAINT FAULTS INDICATED SEVERAL POWER CTL UNIT JAMMED CONDITIONS. IF THIS REPOWERING PROC IS IN THE MAINT MANUAL; IT SHOULD BE REVISITED AND BETTER TRAINING GIVEN TO TECHNICIANS ON WHEN IT CAN BE USED AND WHEN IT CANNOT BE USED.