Sensor+ Reporting Backplane Comm Failure

Symptoms

Backplane Comm Failure error

Explanation of Issue

The CEM+ interfaces with the EEPROM to store a config on the backplane through the Backplane I/O edge connector on the CEM+ control board. If there is no damage or corrosion to the edge connector on the CEM+ or to the backplane, the problem could be deeper.

There are four known causes of this issue:

Corrosion or Electrical Damage to the Backplane
Backplanes that are found to have corrosion, or sustained electrical or physical damage cannot be repaired and must be replaced.

Insufficient Edge Connector Contact
Oxidation may have built up enough over time to cause the pins in the connector on the backplane to no longer provide sufficient contact with the edge connector on the control board.
If the CEM+ is part of a touring rack or loaner stock, it may simply need re-seating.
While the rack is OFF, the CEM+ can be uninstalled then re-installed to allow the pin connectors to refresh their connection with the edge connector. Another thing that can be done is to use a wire brush on the Backplane I/O edge connector (the middle edge connector) to clean off any oxidation.

Backplane EEPROM failure
The EEPROM has been known to fail on occasion due to high voltage events. This chip is socketed and can be replaced, though it may require removing the backplane from the rack to access. If attempting to replace the EEPROM, be careful not to bend the leads under the chip. Also note the pin 1 indicator location. There will be a small indented circle in one corner indicating pin 1. The chip should be installed so that the pin 1 indicator is closest to the CPU I/O header (J2, the middle header).

CPU I2C port damaged
This is often caused by a high voltage event. Typically, this will be on older boards (green boards and early blue boards). 7150B4613 Rev D is more resilient to voltage spikes on the I2C lines from the backplane to the CPU.
Rarely, the damage to the I2C port on the CPU has caused additional damage internal to the CPU. While it may boot, it may additionally throw many other errors.
Most often, this will be the issue.

Fix/Solution

For backplanes:
Please contact ETC or your preferred dealer to order a new backplane

For the CEM+:
Please contact ETC Technical Services to begin the RMA process