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Tektronix 7B53A
100 MHz Dual Timebase
Tektronix 7B53A Timebase plug-in

Compatible with 7000-series scopes

Produced from 1973 to 1992

Manuals – Specifications – Links – Pictures

The Tektronix 7B53A is a 100 MHz dual time base plug-in for 7000-series scopes that was introduced in 1973 and produced until the discontinuation of the 7000 series in 1992.

It succeeded the short-lived 7B52, with sweep mode selection integrated into the time/Div switch, and the older combined trigger level/polarity control replaced with separate, concentric knobs.

The 7B53AN is identical to the 7B53A but omits the circuits needed to drive the alphanumeric readout system provided in 7000-series mainframes.

The TD-1085/U is a military designation for the 7B53AN11 which was used in the AN/USM-281C military version of the 7603 scope.

The TD-1159/U is another military version of the standard 7B53A with readout support.

There does not appear to have been a product sold called simply "7B53". There is a 7B53N, a 7B53A, and a 7B53AN.

Key Specifications

Sweep rates 50 ns/Div to 5 s/Div in 1−2−5 sequence (5 ns with ×10 magnification)
Deflection 10 mV/Div, 100 mV/Div or 1 V/Div, up to 2 MHz
Sensitivity 0.3 Div or 100 mV up to 10 MHz, 1.5 Div or 500 mV up to 100 MHz
Coupling DC, AC (> 30 Hz), AC LF REJ (> 30 kHz), AC HF REJ (30 Hz — 150 kHz)
Input impedance 1 MΩ // 20 pF
Jitter < 1 ns at 75 MHz
  • Dual delayed timebase
  • External trigger inputs for main and delayed
  • Display modes: Main, Intensified, Delayed, Mixed
  • Option 5 for the 7B53A adds a TV Sync Separator (video trigger).
  • Several special custom modifications exist for the 7B53A(N):
    • MOD FB adds a gated X-Y mode for operation with the Rotational Function Generator (RFG) for the Engine Analyzer System (7B53A only)
    • MOD 178H adds an alternate sweep mode, deletes mixed sweep mode
    • MOD 769G adds Delay Gate and Delayed Sweep Gate rear outputs
    • MOD 816J adds Main Trigger and Delayed Trigger In connectors parallel to rear panel interface C1 and C2


Delayed Sweep Gate output

When the delayed timebase trigger source switch is set to INT (pushed in) and the internal connector P613 is in the active position, the DLY'D TRIG IN connector becomes a Delayed Sweep Gate output. This is useful e.g. to connect to a 7D15's arming inputs, or a 7D12/M2's external trigger input. See the 1975 TekScope article linked below.

Variable control

Through an internal jumper, the front-panel variable control (red knob) can be selected to vary either the main sweep, the delayed sweep or the main sweep hold-off. See the 1975 TekScope article linked below.

Use as Delayed Timebase

The 7B53A only works in "triggered after delay" mode when used as a delayed timebase, unlike e.g. the 7B92.

X-Y operation

The 7B53 supports X-Y mode by selecting the "Ampl" position on the Time/Div switch. The X signal can be picked up from a vertical plug-in via the internal trigger path, or applied via the "Main Trig In or Amp In" input, as determined by the Trigger Source switch setting. Sensitivity on the external input is 100 mV/Div, which can be increased to 10 mV/Div by selecting the ×10 magnifier, or decreased to 1 V/Div by pushing the EXT÷10 button.



Year 1973 1976 1980 1984 1990
Catalog price $850 $925 $1,135 $1,515 $2,500
In 2021 Dollars $5,300 $4,500 $3,800 $4,100 $5,300


Custom ICs used in the 7B53A

Page Model Part nos Description Designers Used in
155-0028-00 M018 155-0028-00 155-0028-01 155-0042-00 155-0042-01 155-0042-02 155-0042-03 Miller integrator and delay pickoff Joe Burger 5030 R5030 5031 R5031 1401 1401A 1480 1481 1482 1485 26G1 26G2 26G3 314 335 432 434 4701 5B10N 5B12N 5B31 5B40 5B42 5S14N 7B52 7B53A 7B53N 7L12 7L13 7L14 7L18 7S14 AN/USM-281C RG501 Telequipment D63 Telequipment DM63
155-0049-00 M079G 155-0049-00 155-0049-01 155-0049-02 sweep control with lockout Bill DeVey 335 464 465 466 475 475A 475M 485 5B31 5B40 5B52 5B42 5B44 7B53A 7B80 7B85 7B87 7B92A 7B90P 7B10 7B15 SC502 7B42N AN/USM-281C 067-0657-00
155-0109-00 M120B 155-0109-00 155-0109-01 trigger Gary Vance 5B25N 5B31 5B40 5B42 5B44 5S14N 7B50A 7B53A 7B80 7B85 7B87 7B81P 7B90P 7S14 7612D SC502 SC503 SC504