7B53A

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.

Manuals – Specifications – Links – Pictures

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.

The 7B53N appears to be a 7B52 with just the readout circuit omitted. Internal circuits are nearly identical, except for the missing readout circuits.

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
Features	Dual delayed timebase External trigger inputs for main and delayed Display modes: Main, Intensified, Delayed, Mixed
Options	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

Links

Documents Referencing 7B53A

Patents that may apply to 7B53A

Operation

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.

Links

• TekScope Vol. 7 No. 5, 1975 p.15+: Dave McCullough, Delayed gate aids oscilloscope digital measurements
• Tektronix 7B53A Repair and Alignment by Zenwizard Studios @ YouTube

Prices

Year	1973	1976	1980	1984	1990
Catalog price	$850	$925	$1,135	$1,515	$2,500
In 2023 Dollars	$5,800	$4,900	$4,200	$4,400	$5,800

Pictures

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  left side

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  right side

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  3/4 profile

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  7B53AN

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  7B53AN

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  7B53A

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  TD-1085/U, military version of 7B53AN

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  7B53A Option 5

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  7B53N

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  Right internal of 7B53N

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  Left internal of 7B53N

Components