This may be your problem, I have seen it before:
BCM50 stops functioning
Facts: Business Communications Manager 50 BCM50 BCM50a BCM50e All software versions
Symptoms: BCM50 stops functioning The status and power LEDs on the BCM50 turn solid yellow, then after a few seconds the status LED changes to solid red as the power LED changes to flashing yellow All the telephones connected to the system just flash All the services (voicemail, auto attendant, VoIP, IP sets) are non-functional
Cause: The serial ATA connector that connects to the hard drive became loose due to vibrations during transport.
To re-connect the serial ATA cable, open the BCM50 main unit case.
The following instructions are identical for all three variants of the BCM50 chassis (BCM50, BCM50a and BCM50e).
NOTE: Danger: Electrical shock warning. Disconnect the power cord, telephone cables and network cables before opening the BCM50 main unit.
1. Attach one end of a grounding strap to your wrist and the other end to a grounded metal surface.
2. Turn the main unit over so that the bottom of the unit is facing up.
3. Remove the three case screws (indicated by ·A·) from the back of the unit.
4. Turn the BCM50 unit over so that the top of the unit is facing up.
5. While holding the bottom of the BCM50 case, slide the top of the case back to disengage the locking clips.
6. Lift the top of the case off of the BCM50 unit.
7. The hard drive is located at the rear of the BCM50 unit. Gently disconnect and reconnect the red serial AA cable from the hard drive.
8. Place the top of the case on top of the main unit case. Make sure the side edges of the case are aligned and the front of the top is back about 1 cm (3/8 in.).
9. Slide the top of the case forward until it clicks in place.
NOTE: Do not force the case closed. Use only the screws that were originally used to secure the BCM50 case, using other screws may interfere or damage the BCM50.
10. Turn the main unit over so you can access the screws holes on the bottom of the unit.
11. Insert the three case screws in the back of the unit and tighten them.
12. Turn the main unit over so that the top of the unit is facing up.
13. Reconnect the telephone cables, network cables and the power cord.
SHK Certified (School of Hard Knocks)