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Tektronix 7104
1 GHz mainframe with MCP CRT
Tektronix 7104, front view

Produced from 1978 to 1990

Manuals – Specifications – Links – Pictures

The Tektronix 7104 is a 1 GHz, non-storage 7000-series oscilloscope mainframe that takes two 7000-series vertical plug-ins and two 7000-series horizontal plug-ins. It was introduced in 1978. There is also a rack-mount version, the R7103, albeit with only one horizontal bay.

The scope employs a micro-channel plate (MCP) CRT design to get good screen intensity at high sweep speeds with moderate acceleration voltage. The benefit is especially noticeable at low repetition rates.

The high horizontal speed necessitated using distributed deflection plates also for the horizontal deflection system, which reaches a bandwidth of 350 MHz. Option 2 adds a horizontal delay line to make the high horizontal bandwidth available for X-Y mode at a phase shift of <2° up to 50 MHz, nullable at any frequency up to 250 MHz.

The 7A29 1 GHz vertical amplifier and the 7B15/7B10 time base pair were introduced along with the 7104 to match the system bandwidth.

Val Garuts was the initial project leader. Gene Andrews took over the project lead about half way through the seven year development. John Addis was the Project Engineer for the vertical system. He designed the 7A29 plugin and its H500 and H476 ICs (the latter was also used in the 7104 mainframe). Wink Gross designed the 7104 main vertical amplifier including the channel switch, the main vertical output amplifier and its H477 IC. Dave Morgan designed the mainframe horizontal amplifier, and Art Metz designed the Z axis system. Dennis Hall was the project leader for the CRT. Aris Silzars designed the vertical deflection plate structure and managed the acquisition of the microchannel plate. Conrad Odenthal designed the box lens for the CRT.

Key Specifications

Bandwidth 1 GHz (with 7A29) – rise time < 350 ps
Fastest calibrated sweep 200 ps/Div (with 7B10)
Calibrator 40 mV to 4 V (p-p) in decade steps, 1 kHz; 4 mV to 400 mV into 50 Ω; 40 mA with adapter
Y delay line 51 ns (frequency compensated coax pair)
X-Y phase shift
  • base model: < 2° from DC to 50 kHz
  • Opt. 2: < 2° from DC to 50 MHz (with a pair of 7A19 or 7A29, at least one of which has the variable delay option)
Acceleration voltage 12.5 kV
CRT T7100-31-2 Micro channel plate CRT (154-0783-00), P31 phosphor, 8 × 10 Div. @ 8.5 mm, resolution 17 lines / Div., vertical 2 GHz bandwidth @ 1 V/Div sensitivity
Power consumption 215 W
Dimensions 345 mm (h) × 305 mm (w) × 592 mm (l)
Weight 19.8 kg (43.6 lb)
  • Readout
  • 2 probe power connectors

MCP protection

The Micro Channel Plate's amplification degrades irreversibly with operation, in proportion to the log of total charge passed per display area. For this reason, continued operation with a steady trace and especially at large beam currents must be avoided. The 7104 contains a "limited viewing time" circuit to assist with observing this restriction. At beam currents above 0.2 μA, a yellow indicator illuminates, and the beam will be shut down after 20 minutes. The limit time drops to two minutes at an average beam current of 2 μA, and also limits the average current to that value. Single-shot display current is not affected. Despite this limiter, older instruments often exhibit darkening of the screen around the horizontal center line to some degree (see screen shot).


The 7104 makes extensive use of custom integrated circuits and hybrid circuits, inter alia, the 155-0174-00 Delay Line Compensator, 155-0173-00 Vertical Channel Switch, 155-0176-00 Vertical Output Amplifier, 155-0194-00/01/02/03 CRT Termination, 155-0175-00 Trigger Amplifier, 155-0178-00 Horizontal Output Amplifier, 155-0012-00 Z-Axis controller/amplifier, and 155-0067-02 SMPS controller. The high-speed amplifiers use Hypcon ceramic packages that use elastomer-based frames for coupling chip connections to the circuit board at constant impedance. The signal connections are differential throughout, and the signal path was optimized for matching and low reflection, including the plugin to mainframe card-edge connectors and the use of stripline and coplanar waveguide techniques right up to the CRT.

The 7104's amplifiers use a then novel scheme of "feed-beside" compensation (US Pat. 4.132.958) where instead of matching the HF response to the LF response, the LF response is determined by off-the-shelf operational amplifiers in parallel to the high-speed amplifiers, with a number of adjustable R-C time constants to compensate for thermal and other LF effects. The same technique is employed in the 7A29 amplifier plug-in.

Power Supply

The 7104 uses a switch-mode power supply.

Module A23 (schematic page <14>) contains the mains rectifier, base drive circuitry, and power transistors of the inverter (aka, switcher). These transistors produce a 25 kHz waveform that is fed to the primary of T1310 (120-1183-00), whose secondaries provide the power for the rest of the scope.

Module A24 (also on schematic page <14>) contains the inverter control circuit and rectifiers for the secondaries of T1310. The inverter control circuit uses the 155-0067-02 inverter control IC, which is U1275.

Module A25 (schematic page <15>) contains the low-voltage regulators. There are independently regulated and current-limited sections for the −50 V, −15 V, +5 V, +15 V and +50 V rails. Each section has an opamp and a BJT output transistor in emitter-follower configuration.

The opamps need power, too. To avoid a dependency cycle, the power supplies for the opamps are separate low-current, low-efficiency zener clamps that in no way depend on the −50 V, −15 V, +5 V, +15 V or +50 V regulators. The power supplies for the opamps produce −22 V, −5.6 V, +5.6 V, and +22 V. To avoid exceeding the opamps' limit of 30 V total rail voltage, each opamp either gets −22 V and +5.6 V, or −5.6 V and +22 V, depending on whether it needs more output swing in the positive or negative direction.

The +50 V section produces the reference voltage ("50VS") for the other sections. It uses a 9 V zener diode, VR1412, as a reference.

The dependency relationship of the supplies is:

  • The −50 V, −15 V, +5, and +15 V sections depend on
    • the +50 V supply for reference voltage,
    • the opamp supplies for to power their opamps, and
    • the A24 semi-regulated rectifier outputs
  • The +50 V depends on
    • the opamp supplies (+22 V and −5.6 V) for to power its opamp,
    • the A24 semi-regulated rectifier outputs (−54 and +54 V)
  • The opamps supplies depend on
    • the A24 semi-regulated rectifier outputs
  • The semi-regulated rectifier outputs depend only on mains power to enter tick/burst mode. However, to enter normal mode, a variety of things need to be working properly.


  Year 1980 1984 1990
Mainframe only Catalog price $14,400 $21,380 $29,995
In 2022 Dollars $50,200 $59,200 $66,000
Mainframe with 7A29,
7A29 Opt. 04, 7B15, 7B10
Catalog price $21,730 $31,875 $44,510
In 2022 Dollars $75,800 $88,200 $97,900




CRTs used in the 7104

Page Part nos Description Designers Used in
T7100 154-0783-00 micro-channel plate CRT Dennis Hall Aris Silzars Conrad Odenthal 7104 R7103
T7101 micro-channel plate CRT 7104 R7103

Custom ICs used in the 7104

Page Class Manufacturer Model Part nos Description Designers Used in
155-0009-00 Monolithic integrated circuit Tektronix M001 155-0009-00 horizontal lockout logic Les Larson 7504 7514 7704 7704A R7704 7834 7844 7854 7904 R7903 7904A 7934 7104
155-0010-00 Monolithic integrated circuit Tektronix M004 155-0010-00 chop divider and blanking Les Larson 7504 7514 7704 R7704 7704A 7834 7854 7904 R7903 7904A 7934 7104
155-0011-00 Monolithic integrated circuit Tektronix M012 155-0011-00 clock and chop blanking Les Larson 485 7313 7403N R7403N 7503 7504 7514 7603 AN/USM-281C 7613 7623 7623A 7633 7704 R7704 7704A 7834 7844 7854 7904 7904A R7903 R7912 7912AD 7912HB 7934 7104 R7103 AN/USM-281C
155-0012-00 Monolithic integrated circuit Tektronix M015 155-0012-00 Z Axis Logic Les Larson 485 7504 7514 7704 R7704 7704A 7834 7844 7854 7904 R7903 7904A R7912 7934 7912AD 7912HB 7104 R7103
155-0013-00 Monolithic integrated circuit Tektronix M022 155-0013-00 155-0013-01 horizontal chop and alt. binary Les Larson 7504 7514 7704 R7704 7704A 7834 7854 7904 7904A R7903 7934 7104
155-0067-02 Monolithic integrated circuit Tektronix M091B 155-0067-00 155-0067-02 155-0067-03 SMPS controller Joe Burger Gene Andrews 7704A 7834 7844 7854 7904 R7903 7904 7904A 7934 R7912 7912AD 7912HB 7934 7104 R7103 308 434 485 690 P7001
155-0078-00 Monolithic integrated circuit Tektronix M084 155-0078-xx 155-0273-00 155-0274-00 broadband vertical amplifier John Addis 464 465 466 468 475 475A 475M 485 7834 7844 7854 7904 R7903 R7912 7912AD 7912HB 7104 7A16A 7A16P 7A24 7A26 7A42 067-0587-01 067-0680-00 AM503 PG502 PG508 DC510 DC5010 FG5010
155-0150-00 Hybrid integrated circuit Tektronix H473 155-0150-00 trigger detector Art Metz 7904A 7104 7B10 7B15 7B92A SCD1000
155-0173-00 Hybrid integrated circuit Tektronix 155-0173-00 155-0173-00 155-0173-05 vertical channel switch John Addis Wink Gross 7104 R7103 7904A 7934 EG&G N-AM-173A
155-0174-00 Monolithic integrated circuit Tektronix 155-0174-00 155-0174-00 delay line compensator 7104 SCD1000
155-0175-00 Monolithic integrated circuit Tektronix H476 155-0175-00 155-0175-05 broadband amplifier John Addis Wink Gross Carl Battjes 7904A 7912HB 7934 7104 R7103 7A29 7A29P 7F10 067-0587-02 067-0587-10 11A71 SCD1000 EG&G N-AM-173A
155-0176-00 Hybrid integrated circuit Tektronix H477 155-0176-00 vertical output amplifier Wink Gross 7104 SCD1000
155-0178-00 Hybrid integrated circuit Tektronix H488 155-0178-00 155-0178-05 horizontal output amplifier Dave Morgan 7904A 7912HB 7934 7104
155-0179-00 Hybrid integrated circuit Tektronix H475 155-0179-00 clamp circuit Dave Morgan 7104

Custom ICs used in the 7000 series readout system

Page Class Manufacturer Model Part nos Description Designers Used in
155-0014-01 Monolithic integrated circuit Tektronix M019D 155-0014-00 155-0014-01 A/D converter Barrie Gilbert 7000 series readout system 7854 7934 7J20 7L5 P7001
155-0015-01 Monolithic integrated circuit Tektronix M020F 155-0015-00 155-0015-01 analog data switch Barrie Gilbert 7000 series readout system 7854 7934
155-0017-00 Monolithic integrated circuit Tektronix M025 155-0017-00 5 MHz decade counter Barrie Gilbert 7000 series readout system 7854 7934
155-0018-00 Monolithic integrated circuit Tektronix M026 155-0018-00 zeros logic control Les Larson 7000 series readout system 7934
155-0019-00 Monolithic integrated circuit Tektronix M027 155-0019-00 decimal point and spacing control Les Larson 7000 series readout system
155-0020-00 Monolithic integrated circuit Tektronix M028 155-0020-00 output assembler Les Larson 7000 series readout system
155-0021-00 Monolithic integrated circuit Tektronix M029C 155-0021-00 155-0021-01 timing generator Les Larson 7000 series readout system 7854 7934
155-0023-00 Monolithic integrated circuit Tektronix 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 Monolithic integrated circuit Tektronix M161 155-0024-00 character generator (↓ < I / + - + C Δ >) Barrie Gilbert 7000 series readout system
155-0025-00 Monolithic integrated circuit Tektronix 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 Monolithic integrated circuit Tektronix 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 Monolithic integrated circuit Tektronix M164 155-0027-00 character generator (U N L Z Y P F J Q D) Barrie Gilbert 7000 series readout system