7904A: Difference between revisions
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{{Oscilloscope Sidebar | |||
|manufacturer=Tektronix | |||
|series=7000-series scopes | |||
|model=7904A | |||
|designers= | |||
|image=7904a-front.jpg | |||
|caption=Tektronix 7904A | |||
|introduced=1984 | |||
|discontinued=1990 | |||
|summary=500 MHz non-storage mainframe | |||
|manuals= | |||
* [[Media:070-4593-00.pdf|Tektronix 7904A Manual, May 1989 Revision]] (OCR, low quality scan, whole schematics) | |||
* [[Media:070-4593-00 hires split schematics.pdf|Tektronix 7904A Manual, May 1989 Revision]] (OCR, good quality scan, split schematics) | |||
}} | |||
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]]. | |||
{{BeginSpecs}} | |||
{{Spec | Bandwidth | 500 MHz (with [[7A29]] or [[7A19]] amplifier) }} | |||
{{Spec | Fastest calibrated sweep | 500 ps/div with [[7B10]], [[7B15]], or [[7B92A]] }} | |||
{{Spec | Outputs | Vertical Signal Out (25 mV/Div into 50 Ω, 0.5 V/Div into 1 MΩ); +Sawtooth; +Gate; camera power; probe power }} | |||
{{Spec | 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 }} | |||
{{Spec | 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 | |||
}} | |||
{{Spec | Calibrator | 1 kHz square wave, 40 mV to 4 V in decade steps (4/40/400 mV into 50 Ω); 40 mA current loop }} | |||
{{Spec | Power | 90−132 V or 180−250 V, 48−440 Hz, 210 W nom. }} | |||
{{Spec | Weight | 16.9 kg (37.2 lbs) without plugins }} | |||
{{Spec | Dimensions | 34.5 cm × 30.5 cm × 57.7 cm (13.6 in x 12.0 in x 22.7 in) H×W×L }} | |||
{{Spec|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 | |||
}} | |||
{{EndSpecs}} | |||
==Links== | |||
* [http://amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_mainframe/7904A.htm 7904A] @ amplifier.cd | |||
* [https://www.circuitsathome.com/measurements/repairing-front-panel-buttons-of-tektronix-7904-oscilloscope Repairing front panel buttons of Tektronix 7904 oscilloscope] | |||
* [https://www.youtube.com/watch?v=GQn0EqW-u74 Tektronix 7904A lab check in and LED MOD] by Zenwizard Studios @ YouTube | |||
{{Documents|Link=7904A}} | |||
{{PatentLinks|7904A}} | |||
==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 [[7000-series remote control connector|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 [[7000 series readout system|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== | |||
{| class="wikitable" | |||
|- | |||
! | |||
! Year | |||
! 1984 | |||
! 1990 | |||
|- | |||
! Model | |||
| | |||
|align=center| 7904A | |||
|align=center| 7904A | |||
|- | |||
!rowspan=2| Mainframe only | |||
! Catalog price | |||
|align=right| $8,810 | |||
|align=right| $12,750 | |||
|- | |||
! In 2024 Dollars | |||
|align=right| $26,600 | |||
|align=right| $30,600 | |||
|- | |||
!rowspan=2| Mainframe with [[7A19]],<br />7A19 Opt. 04, [[7B92]] | |||
! Catalog price | |||
|align=right| $17,425 | |||
|align=right| $24,190 | |||
|- | |||
! In 2024 Dollars | |||
|align=right| $52,700 | |||
|align=right| $58,100 | |||
|} | |||
==Pictures== | |||
<gallery> | |||
7904a-front.jpg |7904A | |||
7904A_rear.jpg |7904A Rear | |||
7904A_top1.jpg |7904A Top with Horizontal Amplifier at top right | |||
7904A_right1.jpg |7904A Right with Z-axis on top right and 2nd Gen. Readout board at bottom right | |||
7904A_left1.jpg |7904A Left with Vertical Amplifier (top) and Vertical switch board (bottom) | |||
7904A_topleft1.jpg |7904A Topleft | |||
7904A_left_closeup.jpg |7904A Closeup of Vertical amplifier | |||
7904a lvps1.png|7904A Low-voltage Power Supply Schematic | |||
7904a-h-v.jpg | 7904A Horizontal and vertical amplifiers | |||
</gallery> | |||
==Parts== | |||
{{Parts|7904A}} | |||
{{Custom ICs|7000 series readout system}} | |||
[[Category:7000 series non-storage mainframes]] |
Latest revision as of 04:52, 26 September 2024
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)
|
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 |
|
Links
- 7904A @ amplifier.cd
- Repairing front panel buttons of Tektronix 7904 oscilloscope
- Tektronix 7904A lab check in and LED MOD by Zenwizard Studios @ YouTube
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
-
7904A
-
7904A Rear
-
7904A Top with Horizontal Amplifier at top right
-
7904A Right with Z-axis on top right and 2nd Gen. Readout board at bottom right
-
7904A Left with Vertical Amplifier (top) and Vertical switch board (bottom)
-
7904A Topleft
-
7904A Closeup of Vertical amplifier
-
7904A Low-voltage Power Supply Schematic
-
7904A Horizontal and vertical amplifiers
Parts
Some Parts Used in the 7904A