IBM 5170 - Load Resistor
From the technical reference for the IBM 5170:
"If no fixed disk drive is connected to the power supply, the load resistor must be connected to P10. The load resistor is a 5 ohm, 50 watt resistor."
5 ohm resistor on a 12V line will draw 2.4 amps from that line. This greatly satifies the requirement (found in the 5170 technical reference) that the minimum loading of the +12V line of the 5170's power supply is 2.5 amps.
Below is pictured the load resistor (caged) that IBM supplied in the model of 5170 that had no hard drive. The red wire connects to the +12V contact of the Molex connector.
IBM have not specified why the load resistor is required in place of the hard drive. Proper voltage regulation ?
And it is possible that later models of the 5170's power supply no longer have the requirement.
