7603

Manuals – Specifications – Links – Pictures

The Tektronix 7603 is a general-purpose 100 MHz non-storage, large-screen scope that takes two 7000-series vertical plug-ins and one 7000-series horizontal plug-in.

Variants include the a rack-mount version (R7603), and the AN/USM 281C, a ruggedized 7603 without readout (was also known as 7603N Option 11S) that includes two AM-6565 (7A15AN11) single-trace amplifiers, a TD-1085 (7B53AN11) dual time base, and a clip-on front panel cover with probes and accessories.

Key Specifications

Bandwidth	100 MHz with 7A11, 7A16, 7A17, 7A24, 7A26; 110 MHz with 7A19, 70 MHz with 7A18
Fastest calibrated sweep	5 ns/Div
CRT	Standard: P31 phosphor, 8 × 10 divisions of 1.22 cm (Tek T7400/154-0640-00 tube); 15 kV acceleration (-3/+12); Option 8: P11 phosphor Opt. 4 : P31 phosphor, 8 × 10 divisions of 1.0 cm (Tek 154-0672-00 tube); 18 kV acceleration Opt. 6 : P31 phosphor, 8 × 10 divisions of 1.22 cm (Tek 154-0673-00 tube, spectrum analyzer graticule)
Vertical modes	Left / Alt / Add / Chop / Right
Trigger Source	Left / Vert Mode / Right
Inputs	Z Axis
Outputs	Camera power, Vert signal, +Gate, +Sawtooth
Power	100 / 110 / 120 / 200 / 220 / 240 V, +/- 10%, 50—440 Hz, max. 170 W
Weight	13.6 kg / 30 lb (instrument only)
Operating Environment	0°C – +50°C, < 15,000 ft

Options

Due to the long production time of the 7603 many options were available. As some options became standard (e.g. built-in fan) some numbers were assigned twice. Later models were equipped with an IEC320 mains socket, making all Ax (power cable style) options obsolete.

• Opt.1: Without readout (= 7603N)
• Opt.3: Extra EMI shielding
• Opt.4/Opt.13: Maximum-brightness CRT with reduced area (8x10 cm graticule)
• Opt.5: Fan
• Opt.5 (later models): 400 Hz line frequency
• Opt.6: Spectrum analyzer graticule
• Opt.7: Without Signals Out
• Opt.8: P11 phosphor
• Opt.8 (later models): protective front panel cover, 7603 only
• Opt.11S: Ruggedized variant AN/USM 281C, specified at 50 MHz
• Opt.20: Rear GPIB socket for 7D20, removes +Sawtooth, +Gate, vertical signal outputs, R7603 only
• Opt.76: P7 phosphor
• Opt.77: P7 phosphor with spectrum analyzer graticule
• Opt.78: P11 phosphor

Links

• Detailed repair report @ amplifier.cd (German) / (translated)
• Tek 7603 @ barrytech.com
• Catalog page with specs
• Repair Report #2
• Repair Report #3
• Repair Report #4 - 7603 with 7D20
• EB5AGV's Tektronix R7603 / 7D20 page
• Picture of a completely disassembled 7603
• Håkan's 7603 PSU re-cap
• Zenwizard Studios - Tektronix 7603 Lab Check in and Calibration

Documents Referencing 7603

Document	Class	Title	Authors	Year	Links
Tekscope 1977 V9 N1.pdf	Article	Counter and Oscilloscope Combination Makes Difficult Measurements	Emory Harry	1977	DC505A • 7B53A • 7A18 • 7603

Internals

The 7603 was made in various versions for many years, with revisions to some subassemblies like the vertical output amplifier and HV circuits. A fan is optional.

The vertical output amplifier is built around a 155-0080-00 hybrid (U450). CRT deflection plates are not distributed.

Other custom Tek ICs used include 155-0011-00 clock & chop blanking (U55), 155-0022-00 vertical channel switch (U214), 155-0022-00 trigger channel switch (U324),and the 7000 series readout system chips.

Modifications

Reduce ringing in vertical amplifier

Official Modification 36005 added a ground strap to the vertical amplifier to prevent >1 GHz oscillations.

Plugin backlight power

Like the other 76xx models, the 7603 has a linear supply which does not provide +5 V for lights (A9). There was an official Tek modification to add pushbutton illumination for plugins, which involves adding a regulator, but there is also a quick'n'dirty method from Rolynn Prechtl:

I've done multiple units the cheap and dirty way. No additional regulator, no pulling the LVPS to find a place to add extra components and the best part, no cost.
Look for P90 and P10 on the rear edge of the Main Interface ECB (left side as I remember).
Connect P10-1 (GND) P90-7 or 8 (GND).
Connect P10-2 (+5 V) to P90-4 (+5 V).
Two wires and you're done.
Have experienced no problems with the extra current demand from the +5V regulated supply.

Alternative addition of a simple buck regulator module is depicted in the modifications gallery below.

Prices

	Year	1973	1976	1980	1984	1990
Mainframe only	Catalog price	$1,600	$1,800	$2,260	$2,865	$4,235
	In 2023 Dollars	$11,100	$9,700	$8,400	$8,500	$9,900
Mainframe with 2 × 7A18 + 7B53	Catalog price	$3,520	$3,955	$5,225	$6,880	$10,315
	In 2023 Dollars	$24,300	$21,300	$19,500	$20,300	$24,200

Pictures

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  Tektronix 7603, front view with display

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  Tektronix 7603, front view

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  7603 Option 8 (blue P11 phosphor)

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  7603 demonstrating use of front panel calibrator

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  R7603

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  R7603 Opt 20 rear (with GPIB connector for 7D20

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  R7603 Opt 20 rear (with GPIB connector for 7D20

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  Late model 7603 with microprocessor-based readout

Internal

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  7603, left side - center left: vertical amplifier

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  7603, right side - left: calibrator, center left: readout, center right: cover of HV board

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  7603, top view - top: Z axis board, bottom: horizontal amplifier board

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  HV board (below SN B330000)

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  HV board (later version, DC restorer circuits on daughter boards, neons)

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  Interior view of rear panel showing part of LV regulator board (version without fan)

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  Rear view with LV regulator board flipped out (version without fan)

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  Low voltage regulator board

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  Low voltage regulator board fixed for maintenance

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  Bottom view of backplane. Backplane interconnect board is seen in center, vertical interface and trigger selector piggyback boards on left/top left, logic board on right.

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  Logic board (normally situated on back of main interconnect facing the PSU)

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  Trig Select and Vertical Interface boards

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  Backplane interconnect without Vertical Interface and Trigger Selector piggyback boards

Modifications

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  Pushbutton illumination supply using a small step-down regulator module

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Components

Some Parts Used in the 7603

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	A/D 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