WHILE PERFORMING A HORIZ STAB TRIM CHECK DURING A PREFLT ON AN MD80 ACFT; PLT OPERATES THE STAB TRIM SWITCH TO UP ON THE FO'S CTL WHEEL. STAB LONGITUDINAL TRIM INDICATOR SPRINGS FWD TO ONE DEG WITH A SNAPPING SOUND. STAB TRIM WOULD NOT RESPOND THEREAFTER.

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ON FLT TO ZZZ. ORIGINATION PREFLT ON ACFT. PERFORMING STAB TRIM CHECK. STAB TRIM POINTER POSITIONED AROUND A SETTING OF 10 WHICH IS NORMAL AFTER THE PREVIOUS LNDG. CHECKED CAPT'S TRIM SWITCHES -- OK; CHECKED AUTOPLT TRIM SWITCHES -- OK; CHECKED FO TRIM SWITCH 'DOWN' -- OK; CHECKED FO STAB TRIM SWITCH 'UP' WHEN STAB TRIM POINTER SPRUNG FORWARD TO A SETTING OF APPROX 1. TRIED TO MOVE STAB TRIM WITH FO SWITCHES WITH NO MOVEMENT. WAS ABLE TO MOVE STAB TRIM POINTER WITH HAND FREELY UP AND DOWN WITH NO RESISTANCE. CALLED MAINT. MAINT REMOVED SIDE COVERS TO PEDESTAL TO INSPECT AND MADE A QUICK PROGNOSIS OF SOMETHING BREAKING OR SNAPPING IN THE TAIL SECTION. WE WERE GIVEN ANOTHER ACFT AT THE NEXT GATE AND NOTICED ON TAXI OUT THAT (1ST ACFT) STAB TRIM WAS RESTING FULL DOWN. MY OPINION THINKING ABOUT CONSEQUENCES OF THIS MAINT EVENT SHORTLY AFTER TAKEOFF MIGHT HAVE RESULTED IN SERIOUS CTL PROBLEMS. MY OPINION; THERE SEEMS TO BE GROWING MECHANICAL PROBLEMS FLYING THESE OLDER ACFT. I AM HOPING BY REPORTING THIS SPECIFIC PROBLEM SOMEONE MIGHT SEE AND CORRECT A POSSIBLE FLT CTL MALFUNCTION BEFORE IT HAPPENS DURING A CRITICAL PHASE OF FLT.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE SAW THE MD80 THAT WAS TAKEN OTS WITH THE HORIZ STAB TRIM LEADING EDGE FULL DOWN AS THEY WERE TAXIING OUT WITH A REPLACEMENT MD80. HE WASN'T SURE IF THIS WAS THE ACTUAL POSITION THE STAB TRIM ENDED UP AT WHEN THE TRIM INDICATOR SPRUNG FORWARD WITH A SNAPPING SOUND; OR IF MAINT HAD ALREADY BEGUN TROUBLESHOOTING THE STAB PROBLEM. RPTR STATED HE FLEW THE SAME ACFT ONE WEEK LATER AND NOTICED THE MAINT SIGN-OFF STATED A CABLE HAD BEEN REPLACED. HE SUSPECTS A CABLE FOR THE PRIMARY DRIVE SYSTEM.