The Tektronix TM503B is a 3 Slot Mainframe. The Tm 503B Power Module id a three-compartment-wide mainframe compatible with all TM 500 series of modular instrumentation. Tektronix Power Supply Mainframe features:

Range: 100, Voltage: 90-110, Fuse: 1.6AMP SLOW 250V

Range: 120, Voltage: 108-132, Fuse: 1.6AMP SLOW 250V

Range: 220, Voltage: 198-242, Fuse: 0.8AMP SLOW 250V

Range: 240, Voltage: 216-250, Fuse: 0.8AMP SLOW 250V Rear Interface Option: (A B C)

Limit Input Power: <150 Watts

Limit Input Voltage To <60VDC, <42.4VAC, pk-pk

145 Watts Max. Freq. 50/60Hz.