7704A

The Tektronix 7704A is a modular oscilloscope in the 7000 series that takes two 7000-series vertical plug-ins and two 7000-series horizontal plug-ins.

Manuals – Specifications – Links – Pictures

The 7704A followed the 7704 in 1972, improving bandwidth from 150 to 200 MHz (regular model, optimized for transient response) or 250 MHz (option 9, bandwidth-optimized). The rack-mount version continued to be based on the predecessor and was consequently just named R7704.

The 7704A has a special modular construction. At the bottom is the "A7704 acquisition unit", which contains the power supply, plug-in slots, and main interface board. On top is the "D7704 display unit", which contains the CRT, HV power supply, and output amplifiers for driving the deflection plates of the CRT. These units detach. A large multi-pin connector passes signals and power from the acquisition unit to the display unit. It is important not to damage this connector when assembling or disassembling the units.

An optional component, the P7001 Processing Unit, can be added to a 7704A between the acquisition unit and the display unit. The Acquisition Unit of the 7704A, the P7001 Processor, and the Display Unit of the 7704A are connected by the Acquisition-Processor-Display (APD) Interface shown below.

According to Tekscope May 1972,

Luis Navarro was responsible for the electrical part of the project. Bill Lukens designed the low- and high-voltage power supplies, Jim Cavoretto did the vertical amplifier, and Bill Markwart the CRT readout. Bob Shand was responsible for the mechanical design, with Dave Hoskins and Bill Gordon doing the A7704 Acquisition Unit, Phil Lloyd the D7704 Display Unit, and Dick Swanson and Larry Pearson the interconnect system.

Key Specifications

Fastest cal. sweep	2 ns/Div
Bandwidth	200 MHz (with 7A19)
Calibrator	4 mV to 40 V in decade steps, 2/20/200/400 mV into 50 Ω, 40 mA; 1 kHz
Outputs	Vertical Signal Out (25 mV/Div, 60 MHz), +Sawtooth, +Gate, Cal, camera power, probe power
Acceleration voltage	24 kV
Power	90-132 V or 180-264 V, 48-440 Hz, 180 W max.
Weight	13.6 kg (30 lbs)
Size	34.5 cm × 30.5 cm × 57.7 cm (H×W×L)
Options	Option 1: No Readout Option 3: Extra EMI shielding Option 4: Reduced scan CRT (4x5 cm graticule) Option 7: Deletes signals out (Vertical signal out, +Sawtooth, +Gate, Z-axis in, remote reset input). Readout always free-running. Option 8: Phosphor change (P11, blue) Option 9: Extended bandwidth (250 MHz, trades pulse response)

Links

• 7704A page at amplifier.cd (with repair report, German) / translated
• 7704A demo @ YouTube
• Zenwizard Studios - Tektronix 7704A Calibration

Documents referencing 7704A

Document	Class	Title	Authors	Year	Links
Tekscope 1972 V4 N3 May 1972.pdf	Article	The 7704A – Extended Performance Plus Modularity	Luis Navarro • Bob Shand	1972	7704A
7000 series brochure March 1973.pdf	Brochure	7000 series brochure, March 1973		1973	7A11 • 7A12 • 7A13 • 7A14 • 7A15A • 7A16A • 7A17 • 7A18 • 7A19 • 7A21N • 7A22 • 7B50 • 7B53A • 7B70 • 7B71 • 7B92 • 7CT1N • 7D11 • 7D13 • 7D14 • 7D15 • 7M11 • 7L12 • 7S11 • 7S12 • 7T11 • 7704A • R7704 • 7904 • R7903 • 7603 • R7603 • 7403N • R7403N • 7313 • R7313 • 7613 • R7613 • 7623 • R7623 • P7001
Tekscope 1973 V5 N2 Mar 1973.pdf	Article	The Oscilloscope with Computing Power	Hiro Moriyasu • Luis Navarro • Jack Gilmore • Bruce Hamilton	1973	7704A • P7001
RISOM2873.pdf	Article	Improvement of the Bandwidth of the Transient Digitizers in the LIDAR Thomson Scattering Diagnostic on JET	Erik Kristensen	1990	7912AD • 7A29 • 7704A • 7S12 • S-6 • S-52

Patents that may apply to 7704A

Internals

The vertical amplifier in the 7704A uses the 155-0077-00 hybrid.

In the 7704A, the readout board is located behind a back panel carrying two LEMO S-series connectors for probe power. This placement was intended to allow easy retrofitting of a readout board into an Option 1 instrument, however, the readout board is not a plug-in card − several cables have to be attached to the board.

The 7704A SMPS uses a custom Tek chip (155-0067-02) to implement the control functions. For the initial start of the SMPS oscillator on power-up, early 7704As use a diac and later 7704As use a unijunction transistor in the starter circuit.

Prices

Year	Catalog price	In 2025 dollars
1973	$2,400	~$17,600
1975	$2,600	~$15,700
1977	$2,900	~$15,500
1980	$3,635	~$14,300
1982	$3,995	~$13,400
1984	$4,520	~$14,100
1986	$4,995	~$14,800
1987	$5,635	~$16,100

Pictures

• 7704A displaying a trace

• 7704A displaying a trace

• 7704A

• 7704A

• 7704A + 7D01 (from advertisement)

• 7704A picture from manual

• APD Interface

• Interconnect plug in normal position

• Interconnect plug on storage fixture

• 7704A with P7001

• 7704A rear

• 7704A rear

• 7704A rear

• 7704A Mod 9 rise time with 7A29 is 1.25 ns. Sweep was adjusted for exactly 1 ns / div using 1 GHz reference.

Components

Some Parts Used in the 7704A

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