Ibm Personal Computer Xt Power Supply; Description - IBM XT 5160 Technical Reference

IBM Personal Computer XT Power
Supply
Description
The system dc power supply is a 130-watt, 4 voltage-level
switching regulator. It is integrated into the system unit and
supplies power for the system unit, its options, and the keyboard.
The supply provides 15 A of +5 Vdc, plus or minus 5%, 4.2 A of
+ 12 Vdc, plus or minus 5%, 300 mA of -5 Vdc, plus or minus
10%, and 250 mA of -12 Vdc, plus or minus 10%. All power
levels are regulated with overvoltage and overcurrent protection.
There are two power supplies, 120 Vac and 220/240 Vac. Both
are fused. If dc overcurrent or overvoltage conditions exist, the
supply automatically shuts down until the condition is corrected.
The supply is designed for continuous operation at 130 watts.
The system board takes approximately 2 to 4 A of + 5 Vdc, thus
allowing approximately 11 A of +5 Vdc for the adapters in the
system expansion slots. The + 12 Vdc power level is designed to
power the internal diskette drives and the 10M or 20M fixed disk
drive. Th.e -5 Vdc level is used for analog circuits in the diskette
adapter's phase-lock loop. The + 12 Vdc and -12 Vdc are used
for powering the Electronic Industries Association (EIA) drivers
for the communications adapters. All four power levels are
bussed across the eight system expansion slots.
The IBM Monochrome Display has its own power supply,
receiving its ac power from the system unit's power system. The
ac output for the display is switched on and off with the Power
switch and is a nonstandard connector.
Power Supplies 3-3