7503

Manuals – Specifications – Links – Pictures

The Tektronix 7503 is a 90 MHz 7000-series mainframe with three module bays, introduced in 1970. It was effectively replaced by the larger-screen 7603 in 1972.

The 7503 project was managed by Phil Crosby, and was supposed to be a 7504 but with one fewer plug-in. The 7503 was Tek's first scope to use a harmonica connector for inter-board wiring. Prior to this, inter-board wiring had either mainly been point-to-point soldered. Other approaches were taken on certain instruments, for example the 7704, in which pins sticking out of the chassis mate with holes in the boards that receive the pins and make electrical contact.

Unlike later three-slot (7xx3) mainframes, the 7503 does supply the +5 V lamp rail, which helps with the contemporary 7A12 plug-in. It also features the 7000-series remote control connector at the rear of the unit.

Key Specifications

Bandwidth	90 MHz with 7A11, 7A16 (and faster plug-ins); 75 MHz with 7A12, 7A13, 7A14
Fastest calibrated sweep	5 ns/Div
CRT	T7500 (154-0608-xx), 18 kV total acceleration (+15/−2.96)
Calibrator	4 mV to 40 V in five decade steps, 40 mA, 1 kHz ±0.5%
Outputs	Side panel: Vert signal, +Gate, +Sawtooth; At CRT: Camera power
Power	90−110 V / 104−126 V / 112−136 V / 180−220 V / 208−252 V / 224−272 V, 50−440 Hz; max. 258 W
Weight	21.3 kg / 47 lb (instrument only)
Rear connectors	High speed Z Axis input (BNC connector, 60 Vp-p, 75 MHz) High sensitivity Z Axis input (BNC connector, 2 Vp-p, 10 MHz) Two LEMO S-series connectors for probe power Amphenol 165-16 connector (J1075) for remote control (single sweep ready/reset signals)

Links

Documents Referencing 7503

Document	Class	Title	Authors	Year	Links
Tekscope 1970 V2 N3 Jun 1970.pdf	Article	The 7000-Series Oscilloscopes as Signal Sources		1970	7704 • 7504 • 7503
Tekscope 1970 V2 N5 Oct 1970.pdf	Article	Amplitude Measurement to Better Than 1%		1970	1S1 • 7503 • 7A13 • 1A5 • W • 3A7

Patents that may apply to 7503

Internals

In addition to two custom Tek ICs, the 7503 uses CA3046 transistor arrays (156-0048-00) in eight places (five on the regulator board). The vertical and horizontal amplifiers are built using discrete transistors.

The 7503 has an X-Y delay compensation network that is activated when the H plugin is an amplifier or a timebase in amplifier mode (see 7000 Series plug-in interface). This network is switched in using a pair of 148-0034-00 miniature relays on the horizontal amplifier board.

Like other 75xx and 76xx mainframes and the 7504, the 7503 has a linear power supply, as opposed to the switchmode supplies used in the later 4-slot mainframes. In addition to the +5 V, ±15 V, ±50 V rails common to the 7000 series, internally (not on the plug-in slots) it has a +75 V output not found in later models, and a +150 V instead of the later +130 V.

The 7503 contains a mercury-based elapsed time meter on the rear of the main interface board.

Pictures

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  Front

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  Plug-in bay

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  Plug-in connectors missing sides

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  7503 backplane PCB mid-repair

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  Horizontal amp on top

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  Vertical amp on the side

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  Left view, delay cable, CRT

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  Left view, power supply

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  Right view, mains frequency transformer

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  Readout board

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  Right side connector panel

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  Rear

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Components

Some Parts Used in the 7503

Custom ICs used in the 7000 series readout system

Page	Model	Part nos	Description	Designers	Used in
155-0014-01	M019D	155-0014-00 • 155-0014-01	analog-to-decimal converter	Barrie Gilbert	7000 series readout system • 7854 • 7934 • 7J20 • 7L5 • P7001
155-0015-01	M020F	155-0015-00 • 155-0015-01	analog data switch	Barrie Gilbert	7000 series readout system • 7854 • 7934
155-0017-00	M025	155-0017-00	5 MHz decade counter	Barrie Gilbert	7000 series readout system • 7854 • 7934
155-0018-00	M026	155-0018-00	zeros logic control	Les Larson	7000 series readout system • 7934
155-0019-00	M027	155-0019-00	decimal point and spacing control	Les Larson	7000 series readout system
155-0020-00	M028	155-0020-00	output assembler	Les Larson	7000 series readout system
155-0021-00	M029C	155-0021-00 • 155-0021-01	timing generator	Les Larson	7000 series readout system • 7854 • 7934
155-0023-00	M160	155-0023-00	character generator (0 1 2 3 4 5 6 7 8 9)	Barrie Gilbert	7000 series readout system
155-0024-00	M161	155-0024-00	character generator (↓ < I / + - + C Δ >)	Barrie Gilbert	7000 series readout system
155-0025-00	M162	155-0025-00	character generator (m μ n p X K M G T R)	Barrie Gilbert	7000 series readout system
155-0026-00	M163	155-0026-00	character generator (S V A W H d B c Ω E)	Barrie Gilbert	7000 series readout system
155-0027-00	M164	155-0027-00	character generator (U N L Z Y P F J Q D)	Barrie Gilbert	7000 series readout system