THS720
The Tektronix THS720 is a portable 100 MHz bandwidth 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.
Operation
Due to the isolated inputs, the probe ground must be connected even when compensating the probes with the "PROBE COMP" output. It can be used with any BNC probe but the scale factor pin found on many Tektronix probes is not used. The vertical menu has a scale factor entry (1X, 10X, 100X, 1000X) which can also be used for direct BNC inputs.
Recommended probes are the P5102 and the P6113B, both are 10X probes with protected grounds for isolated measurements.
Internals
Primary microprocessor is the Motorola/Freescale MC68331CFC16. There is also an Intel flash E28F008SA120 for setup, cal and waveform storage.
Repair Issues
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.
See THS700.
Pictures
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THS720 Std displaying probe compensation waveform
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THS720 std top of main PCB
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THS720 std main board MCU and DMM
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THS720 std main board BNC inputs and power supply
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THS720 std back of main PCB
