check your transmission.
ZYMO:ET,xx;
(%) EFS
LOCAL END 100.00
REMOTE END 100.00
If your counter is 100%, you don’t have problem on your PCM (BSC to BTS)
Check your câble:
-poor contact
-connect all the masses with the ground
Good luck, i have been a similiar problem for 3 month. It was a bad ground.