7904A

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Tektronix 7904A
500 MHz non-storage mainframe
Tektronix 7904A

Produced from 1984 to 1990

Manuals
(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix 7904A is a 500 MHz, non-storage 7000-series oscilloscope mainframe with four bays, introduced in 1984. It is a redesign of the predecessor model 7904 from 1971, using integrated circuits developed for the 1 GHz 7104.

Key Specifications

Bandwidth 500 MHz (with 7A29 or 7A19 amplifier)
Fastest calibrated sweep 500 ps/div with 7B10, 7B15, or 7B92A
Outputs Vertical Signal Out (25 mV/Div into 50 Ω, 0.5 V/Div into 1 MΩ); +Sawtooth; +Gate; camera power; probe power
Z axis input +2 V to blank from max. intensity, –2 V to unblank from min, intensity; 1 MHz BW; 470 Ω // 50 pF; max. 15 V DC+ peak AC
CRT

Acceleration voltage 24 kV (+21 / –3 kV)

  • Standard: 8×10 Div @ 1 cm, P31 (green): 154-0644-05/154-0893-05, 1.25 cm/ns
  • Option 78, 8×10 Div @ 1 cm, P11 (blue): 154-0644-09, 2.5 cm/ns
  • Option 4, 8×10 Div @ 0.5 cm, P31 (green): 154-0661-05, 2 cm/ns
  • Option 13, 8×10 Div @ 0.5 cm, P11 (blue): 154-0661-10, 4 cm/ns
Calibrator 1 kHz square wave, 40 mV to 4 V in decade steps (4/40/400 mV into 50 Ω); 40 mA current loop
Power 90−132 V or 180−250 V, 48−440 Hz, 210 W nom.
Weight 16.9 kg (37.2 lbs) without plugins
Dimensions 34.5 cm × 30.5 cm × 57.7 cm (13.6 in x 12.0 in x 22.7 in) H×W×L
Options
  • Opt.1: deletes read out system
  • Opt.2: X-Y delay compensation network
  • Opt.3: Extra EMI shielding
  • Opt.4: Maximum-brightness CRT with reduced area
  • Opt.78: P11 phosphor

Links

Documents Referencing 7904A

(no results)

Internals

The 7904A incorporates a 65 ns Y delay line. This delay is too short for some older time bases such as 7B53 to display the trigger event. The signal path is completely differential and the internal signal wiring is 50 Ω coax. The CRT (154-0644-05) has distributed vertical deflection plates.

Differences to 7904

The 7904A borrows heavily from the 1 GHz 7104 introduced in 1978 in terms of front panel layout, mechanical design, and electronics, re-implementing the vertical amplifier using Hypcon-packaged amplifier chips such as the 155-0173-05, 155-0175-05 and 155-0178-05.

The 7904 had the elaborate 5-decade built-in calibrator with variable rate that was common on all first-generation 4-bay 7000-series scopes, it was dropped from the 7904A. The rear remote control connector unique to early 7000-series scopes was dropped as well. In the 7904A, The Control Illumination switch moved to the rear panel, and the readout system gained a pulsed mode in which it is synchronized with the sweep instead of interrupting the display at random times. This pulsed mode is not compatible with all time base plug-ins (see manual p. 1-12).

In addition, the 7904A adds a fan in the SMPS.

Prices

  Year 1984 1990
Model 7904A 7904A
Mainframe only Catalog price $8,810 $12,750
In 2024 Dollars $26,600 $30,600
Mainframe with 7A19,
7A19 Opt. 04, 7B92
Catalog price $17,425 $24,190
In 2024 Dollars $52,700 $58,100

Pictures

Parts

Some Parts Used in the 7904A

Part Part Number(s) Class Description Used in
148-0034-00 148-0034-00 Discrete component miniature DPDT relay 5A48 7A11 7A13 7A14 7B70 7B71 7503 7904 7904A
154-0644-00 154-0644-00 154-0644-04 154-0644-05 154-0644-09 154-0893-05 CRT CRT with distributed deflection plates 7704A 7854 7904 7904A R7903
155-0009-00 155-0009-00 Monolithic integrated circuit horizontal lockout logic 7504 7514 7704 7704A R7704 7834 7844 7854 7904 R7903 7904A 7934 7104
155-0010-00 155-0010-00 Monolithic integrated circuit chop divider and blanking 7504 7514 7704 R7704 7704A 7834 7854 7904 R7903 7904A 7934 7104
155-0011-00 155-0011-00 Monolithic integrated circuit clock and chop blanking 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
155-0012-00 155-0012-00 Monolithic integrated circuit Z Axis Logic 485 7504 7514 7704 R7704 7704A 7834 7844 7854 7904 R7903 7904A R7912 7934 7912AD 7912HB 7104 R7103
155-0013-00 155-0013-00 155-0013-01 Monolithic integrated circuit horizontal chop and alt. binary 7504 7514 7704 R7704 7704A 7834 7854 7904 7904A R7903 7934 7104
155-0022-00 155-0022-00 155-0022-01 Monolithic integrated circuit analog multiplexer 147 148 149 335 468 1430 1441 1461 1900 1910 2220 2221 2230 5223 5403 5440 5441 5443 5444 5A38 7313 7403N 7503 7504 7514 7603 AN/USM-281C 7613 7623 7623A 7633 7704 R7704 7704A 7834 7844 7854 R7912 7912AD 7912HB 7904 R7903 7904A 7934 7A12 7A18 7A18A 7A18N 7B52 7B53N 7D10 7D11 7D12 NT-7000 P7001
155-0067-02 155-0067-00 155-0067-02 155-0067-03 Monolithic integrated circuit SMPS controller 7704A 7834 7844 7854 7904 R7903 7904 7904A 7934 R7912 7912AD 7912HB 7934 7104 R7103 308 434 485 690 P7001
155-0150-00 155-0150-00 Hybrid integrated circuit trigger detector 7904A 7104 7B10 7B15 7B92A SCD1000
155-0173-00 155-0173-00 155-0173-05 Hybrid integrated circuit vertical channel switch 7104 R7103 7904A 7934 EG&G N-AM-173A
155-0175-00 155-0175-00 155-0175-05 Monolithic integrated circuit broadband amplifier 7904A 7912HB 7934 7104 R7103 7A29 7A29P 7F10 067-0587-02 067-0587-10 11A71 SCD1000 EG&G N-AM-173A
155-0178-00 155-0178-00 155-0178-05 Hybrid integrated circuit horizontal output amplifier 7904A 7912HB 7934 7104

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