7704

Manuals – Specifications – Links – Pictures

The Tektronix 7704 is a 150 MHz, four-bay mainframe, one of the initial oscilloscopes introducing the 7000-Line in August 1969.

It is very lavishly built, using contacts embedded in the aluminium frame for interconnecting the gold plated circuit boards. It also features the 7000-series remote control connector on the rear panel.

It can take two 7000-series vertical plug-ins and two 7000-series horizontal plug-ins.

It was superseded by the completely redesigned 7704A in 1973. There is also a rack-mount version, the R7704, that was produced until 1985, still with the original specifications (150 MHz) of the 7704.

Key Specifications

Bandwidth	150 MHz (with 7A11 or 7A16)
Fastest calibrated sweep	2 ns/Div
Calibrator	DC, square wave (1 kHz or 1/2 B Sweep gate), 4 mV to 40 V in decade steps (2/20/200/400 mV into 50 Ω); 40 mA current loop
Vertical modes	Left / Alt / Add / Chop / Right
Horizontal modes	A / Alt / Chop / B
Trigger Source	Left / Vert Mode / Right
Inputs	Z Axis High Speed (60 Vp-p, DC−100 MHz) Z Axis High Sensitivity (2 Vp-p, DC−2 MHz; 0.4 Vp-p @ 20 MHz)
Outputs	Vertical Signal Out (25 mV/Div into 50 Ω, 0.5 V/Div into 1 MΩ) +Sawtooth +Gate camera power probe power
CRT	8x10 Div @ 1cm/Div internal gradicule, 154-0609-00 distributed vertical deflection plates, with P31 phosphor, 24 kV acceleration (+21/-2.96)
Options	Opt.01 – without readout Opt.02 – X-Y compensation network Opt.03 – EMI shielding
Power	90−136 V or 180−272 V, 48−440 Hz, 210 W max.
Weight	19.1 kg (42 lbs)
Size	34.2 cm × 30.5 cm × 55.1 cm (H×W×L) (13.5 in x 12.0 in x 21.7 in)

Operation

The 7704 has several modes of operation, all outlined in the manual:

Single-Trace Display

Vertical Mode: Left, Horizontal Mode: A. Single-trace vertical plugin installed in the left vertical compartment, single-timebase plugin installed in horizontal compartment A.

Provides a display of a single-trace vertical unit against one time-base unit.

Note: Any combination of one vertical and one horizontal plugin can be chosen as needed.

Dual-Trace Display

Vertical Mode: Alt or Chop, Horizontal Mode: A. Single-trace vertical plugins installed in both vertical compartments, single-timebase plugin installed in horizontal compartment A.

Provides a display of two single-trace vertical units against one time-base unit.

Dual-Sweep Display

Vertical Mode: Left, Horizontal Mode: Alt or Chop. Single-trace vertical plugin installed in the left vertical compartment, single-timebase plugins installed in both horizontal compartments.

Provides a dual-sweep display of a single-trace vertical unit against two time-base units.

Dual-Trace/Dual-Sweep Display

Vertical Mode: Chop, Horizontal Mode: Alt or Chop. Single-trace vertical plugins installed in both vertical compartments, single-timebase plugins installed in both horizontal compartments.

Provides a dual-trace, dual-sweep display of two single-trace vertical units against two time-base units (four total traces)

Sweep-Slaving Display

Vertical Mode: Alt, Horizontal Mode: Alt or Chop. Single-trace vertical plugins installed in both vertical compartments, single-timebase plugins installed in both horizontal compartments.

Provides a dual-trace, dual-sweep display where the left vertical plugin is displayed at the sweep rate of the B timebase plugin, and similarly for the right vertical and A horizontal plugins.

Delayed-Sweep Display

Vertical Mode: Left, Horizontal Mode: Alt or Chop. Single-trace vertical plugin installed in the left vertical compartment. Delaying timebase plugin installed in horizontal compartment A, and a single-timebase plugin installed in horizontal-compartment B.

Provides a simultaneous display of a delaying timebase and delayed timebase, providing an effective "zoom" function.

X-Y Display

Vertical Mode: Left, Horizontal Mode: A. Single-trace vertical plugins installed in both the left vertical compartment and the A horizontal compartment.

The X signal is input into the A horizontal plugin while the Y signal is input into the left vertical plugin. Alternatively, some 7B series timebase plugins include X-Y capability.

Due to the modular design of the instrument, there are many more possible modes of operation. For example, horizontal plugins can be installed in both the vertical and horizontal plugins to provide a raster display, or dual-trace plugins can be used in any of the above configurations.

Internals

The 7704 was the first Tek lab scope to employ a switch-mode power supply (SMPS). The SMPS, designed by Gene Andrews, uses an all-discrete resonant half-bridge topology. The CRT voltages and heating are produced in a separate switching stage running off the main SMPS DC output.

Logic, channel switching, and readout use the classic TEK 7000 series custom ICs (155-0009-00 to 155-0022-00), the vertical amplifier (also designed by Andrews) and the horizontal amplifier are completely discrete.

The 7704 does not implement the Aux Y input (B16), therefore the Trace Separation control on a 7B92/7B92A will have no effect. (This was implemented on the 7704's successor, the 7704A.)

The 7704 contains a mercury-based elapsed time meter on the low voltage regulator board.

Links

• Tek 7704 @ barrytech.com

Documents Referencing 7704

Document	Class	Title	Authors	Year	Links
Tekscope 1969 V1 N5 Oct 1969.pdf	Article	Introducing the New Generation		1969	7000-series scopes • 7504 • 7704 • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7S11 • 7M11 • 7B50 • 7B51 • 7B70 • 7B71 • 7T11 • R5030 • 7000 series readout system • Miniature relays • Cam switches • Industrial Design • T7500 • T7700 • P6052 • P6053 • C-50 • C-51 • 204-2
Tekscope 1969 V1 N6 Dec 1969.pdf	Article	A New Logic for Oscilloscope Displays		1969	7000-series scopes • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7B50 • 7B51 • 7B70 • 7B71 • 7S11 • 7T11 • 7504 • 7704
Tekscope 1970 V2 N3 Jun 1970.pdf	Article	The 7000-Series Oscilloscopes as Signal Sources		1970	7704 • 7504 • 7503
Tekscope 1971 V3 N2.pdf	Article	Servicing the 7704 High-Efficiency Power Supply	Charles Phillips	1971	7704
Tekscope 1971 V3 N3 May 1971.pdf	Article	Servicing the 7704 CRT Circuit	Charles Phillips	1971	7704

Patents that may apply to 7704

Pictures

• 

  7704 front

• 

  7704 rear

• 

  7704 CRT and controls

• 

  Left internal

• 

  Right internal

• 

  Left side of 7704 contains power supply

• 

  Right side of 7704 contains readout circuitry

• 

  A 7704 displaying the output of a function generator.

R7704

• 

  R7704 front

• 

  R7704 front left (Screen)

• 

  R7704 front right (plugin bay)

• 

  R7704 rear

• 

  R7704 rear left

• 

  R7704 rear right

Components

Some Parts Used in the 7704

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