Table 2-2. Generator Set Troubleshooting (Cont) Malfunction Probable  cause Corrective   action 14. Noisy turbo- charger   (Continued) b. Excessive turbo- charger  impeller end  play. b. Measure  end  play  (para  14-52). Disassemble  and  add  correct number  of  shims  (para  14-52 and 14-55). a. Inspect  turbocharger.  Replace shaft seal ring (para. 14-53, thru 14-55). 15. Turbocharger leaks oil Worn or broken turbocharger shaft  seal ring. Worn or broken turbocharger oil  pressure and drain seal rings. b. Inspect  turbocharger.  Replace turbocharger oil pressure and drain seal rings (para 14-53 thru 14-55). 16. Excessive gear  noise around  front of  engine Defective vibration dampener. a. Inspect  vibration  dampener. Replace  vibration  dampener (para  14-60,14-61  and  14-63). a. Inspect  timing  gears  (para 14-73).  Replace  timing gears  (para  14-72  and  14-75). Excessive  tim- ing gear backlash. b. 17. Low engine compression Defective piston  rings. Replace  piston  rings  (para 14-81 thru 14-83). a. a. Replace  pistons  (para  14-81  and 14-83)  and  cylinder  sleeves (para 14-85 thru 14-87). b. Defective pistons  and cylinder sleeves. b. Leaking  or defective valves. c. Isolate  trouble  (para  14-77). Replace valves (para 14-77 thru 14-79). c. 18. Main  generator output   voltage too  low Exciter- regulator defective. Check exciter regulator (para 8-3). Replace  exciter  voltage  regulator (para 8-10 thru 8-14). a. a. Rotor  assembly defective. Check  rotor  resistance. Check  for  shorts  or grounds. Replace, repair or  rebuild  if  required  (para  9-2, 9-3,9 -4,9-6 and 9-7). c.  Stator defective. c. Check  stator  resistance. Check  for  grounds  or  shorts. Replace,  repair  or  rebuild if required (para 9-2, 9-3, 9-4, 9-6 and 9-7). d. Exciter  rotor defective. Check  exciter  resistance. Check  for  shorts  or  grounds (para  9-2).  Replace  exciter if defective. (para 9-5, 9-6 and  9-7). e. Exciter stator defective. Check exciter stator resistance. Check  for  shorts  or  grounds (para 9-2). Replace exciter stator (para 9-5,9-6 and 9-7). e. 2-14