Voltage Out of Range

Even though all voltages within the chassis are regulated, situations can arise where a voltage drifts outside of the acceptable range and goes too high or too low.

When a voltage is too high, it can be caused by:

• The load for which the voltage is provided, is missing – A component has failed or has been removed from the electrical connection.

• The regulator for that voltage has failed.

For example, if the voltage at sensor target /SYS/MB/V_I41.2V is too high, then either the regulator is failing, or the I4 switch chip is no longer requiring the supplied voltage. This latter situation can occur transitionally if the I4 switch chip is reset or if all of its ports are disabled. If the I4 switch chip has a catastrophic failure, such as from overheating, the voltage at the sensor target might go too high.

When a voltage is too low, it can be caused by:

• The load for which the voltage is provided, has increased beyond that supported by the regulator - A component has either been overresourced or internally electrically shorted, internal maximum temperature has been exceeded, or the electrical connection has been shorted.

• The regulator for that voltage has failed.

For example, if the voltage at sensor target /SYS/MB/V_I41.2V is too low, then either the regulator is failing, or the I4 switch chip is under very heavy throughput loading, quite possibly in conjunction with overheating.

Because both types of voltage extremes for the /SYS/MB/V_I41.2V sensor target can be indicative of a thermal problem with the I4 switch chip, it follows that a check of the temperature at sensor target /SYS/MB/T_I4A, is in order.

Related Information

• Evaluate a Voltage Sensor

• Voltage Sensor Values