in fact we are also facing the same problem, TRE5 of SectorGSM C,after lock/unlock TRE got busy but after some time it went down again
what we have done so far is:
-changed the TRE
-changed the CSO3 cable
-changed the port of the ANC
-changed the slot of TRE
-done the offline comissioning of SUMA
what next? please suggest if im missing some thing….