The Tektronix THS720 is a portable 100 MHz 500 MS/s (each channel) two channel digital oscilloscope. There were two variants, the THS720 STD and the THS720A. The primary difference is that the THS720A will trigger from the DMM input.
Primary microprocessor is the Motorola/Freescale MC68331CFC16. There is also an Intel flash E28F008SA120 for setup, cal and waveform storage.
The service manual shows how to remove the calibration protection jumper. The DMM calibration step requires a good calibrator capable of doing 850 VDC, and 600 VAC at 500 Hz.