7B70
The Tektronix 7B70 is a 200 MHz time-base plug-in for 7000-series scopes. It has no delay function.
For delayed-sweep applications, the 7B70 is operated in conjunction with the model 7B71 delaying timebase. The 7B70/7B71 were primarily intended for the 7704 mainframe.
The task of designing the 7B70 was inherited and completed by Murlan Kaufman.
The 7B71/7B70 were superseded by the 7B85/7B80 pair (400 MHz) in 1976.
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 |
| External horizontal amplifier | 25 mV/Div or 250 mV/Div ranges, variable |
X-Y operation
The 7B70 has a dedicated switch to put it in "amplifier mode" for X-Y operation. In this mode, the Trigger Source switch controls the signal source – internal from a vertical plug-in via the trigger path, or external — and the Trigger Coupling switch controls AC vs. DC coupling.
In amplifier mode, gain can be varied using an uncalibrated potentiometer.
Links
- Troubleshooting the 7B70 and 7B71 timebases. Tekscope Vol.6 No.4 Sept/Oct 1974
- Tek 7B70 @ barrytech.com
- Tek 7B70 @ amplifier.cd
Internals
The 7B70 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.
Pictures
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7B70, front panel
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7B70, left side
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7B70, right side
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