7B71
The Tektronix 7B71 Delaying Time Base is a 200 MHz time base plug-in for 7000-series scopes. It was designed by Murlan Kaufman.
The 7B71 contains a delay function to control a "B" horizontal plug-in in four-slot mainframes, typically a model 7B70. It has no provision for X-Y mode.
The 7B70/7B71 were primarily intended for the 7704 mainframe. They were superseded by the 7B85/7B80 pair (400 MHz) in 1976, which increased the frequency range to 400 MHz and added digital read-out of the delay time.
Key Specifications
| Sweep | 5 s/Div to 20 ns/Div in 1−2−5 sequence, ×10 magnifier down to 2 ns/Div, variable down to 12.5 s/Div |
|---|---|
| Excluded portions of sweep | None in 7700-series, first 50 ns with magnifier |
| Trigger sensitivity | 0.3 Div (int) or 75 mV (ext) up to 20 MHz, 1.5 Div or 375 mV from 20 MHz to 200 MHz |
| Trigger coupling | DC, AC (>30 Hz), AC HF REJ (30 Hz to 50 kHz), AC LF REJ (>30 kHz) |
| Trigger input | 1 MΩ // 20 pF, max. 500 V DC+peak AC |
| Jitter | less than 1 ns at 150 MHz |
| Trigger Modes | Peak-Peak Auto, Auto, Norm, Single Sweep |
| Variable time delay accuracy | 1% (0.5 s/Div to 1 μs/Div) |
| Variable time delay multiplier Linearity | within 0.2% |
Internals
The 7B71 contains five 148-0034-00 miniature relays and one 148-0035-00. It also contains one 152-0154-00 and two 152-0125-00 tunnel diodes.
Links
- Troubleshooting the 7B70 and 7B71 timebases. Tekscope Vol.6 No.4 Sept/Oct 1974
- Tek 7B71 @ barrytech.com
- Tek 7B71 @ amplifier.cd
- Zenwizard Studios - Tektronix 7B71 Repair and Partial Alignment
