86

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The Tektronix Type 86 is a single-input amplifier plug-in for 580-series scopes, introduced in 1963.

The P6008 voltage probe was designed for use with the Type 86.

Units with serial numbers before 1997 use a rotary input switch for the input coupling. Starting with serial number 1997, a lever switch is used.

Key Specifications

Input impedance	1 MΩ // 15 pF
Bandwidth	85 MHz at 100 mV/cm, 80 MHz at 10 mV/cm (in mainframe)
Rise time	×1 mode, 1.5 ns from 100 mV/Div to 20 V/Div; ×10 mode, 2.2 ns from 10 mV/Div to 2 V/Div
Deflection	×1 mode, 100 mV/Div to 50 V/Div;  ×10 mode, 10 mV/Div to 5 V/Div; 1−2−5

Internals

The signal path in the Type 86 begins with a 7586 nuvistor as a cathode follower, feeding a differential transistor-based stage. In ×10 gain, this is followed by three more differential transistor gain stages. Finally, a distributed amplifier with three 6DJ8s drives the mainframe interface.

Like for the Type 82 plug-in, 585 non-A scopes with serial numbers before 2585 should have the back termination of the final distributed amplifier output modified to the later circuit (modification 040-275).

Prices

Year	1965	1969
Type 86 + P6008	$350	$385
2020 value	$2,880	$2,710

Pictures

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  Late serial number Type 86 with lever input coupling switch