As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LH REV UNLOCK CAUTION MSG ON TAKEOFF. ABORTED TAKEOFF AT 50 KNOTS. MAX BTMS READINGS 7612. RETN TO GATE. C/W M ACTION OF MEL 78-30-01. REF 348418/1 FOR TR MEL ***AIRCRAFT REMOVED FROM SERVICE*** SEE W/O 309759 MWC'S #5 & 6 FOR R&R OF LH ENG MICROSWITCH BRACKET ASSEMBLY. OPS CHECK GOOD. REMOVED PLACARD REMOVED MEL. REF AMM 78-37-01.