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{{Oscilloscope Sidebar| | {{Oscilloscope Sidebar | ||
|manufacturer=Tektronix | |||
image=Tek-7904-front.jpg | | |series=7000-series scopes | ||
caption=Tektronix 7904 (with [[7A19]], [[7A11]], [[7D11]], [[7B85]]) | | |model= 7904 | ||
introduced=1971 | | |designers=Val Garuts;Thor Hallen;John McCormick;Les Larson;Bill DeVey;Bill Peek;Hans Springer;Joe Burger;Joel Swanno;Ken Hawken | ||
discontinued=1990 | | |image=Tek-7904-front.jpg | ||
summary=500 MHz non-storage mainframe| | |caption=Tektronix 7904 (with [[7A19]], [[7A11]], [[7D11]], [[7B85]]) | ||
manuals= | |introduced=1971 | ||
* [ | |discontinued=1990 | ||
* [ | |summary=500 MHz non-storage mainframe | ||
* [ | |manuals= | ||
* [ | '''7904''' | ||
* [ | * [[Media:070-1399-00.pdf|Tektronix 7904 Operators Manual]] | ||
* [[Media:070-2390-00.pdf|Tektronix 7904 Instruction Manual with PSU Schematics]] SN B260000+ (OCR) | |||
* [[Media:Servicing the Tek 7904 Power Supply.pdf|Servicing the 7904 High-Efficiency Power Supply]] | |||
* [[Media:Tektronix - 7904 - Horizontal Amplifier B010100 - B079999.pdf|Horizontal Amplifier SN B010100 - B079999]] | |||
'''7904A''' | |||
* [[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) | |||
<small> | <small> | ||
'''Modifications''' | '''Modifications''' | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-0650-00.pdf 050-0650-00 (1980) Vertical amplifier IC replacement] | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-0651-01.pdf 050-0651-01 (1975) Vertical output IC replacement (155-0065-00)] | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-0706-01.pdf 050-0706-01 (1980) Vertical output IC replacement (155-0065-00)] | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-0729-06.pdf 050-0729-06 (1980) A Trigger selector circuit board replacement] | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-0730-06.pdf 050-0730-06 (1980) B Trigger selector circuit board replacement] | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-0763-03.pdf 050-0763-03 (1981) Vertical interface circuit board replacement] | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-1014-00.pdf 050-1014-00 (1980) Vertical output IC replacement] ([[155-0064-00]]) | ||
* [ | * [https://hakanh.com/dl/docs/kitinstructions/050-1723-01.pdf 050-1723-01 (1983) P31 CRT replacement] | ||
* [ | * [https://hakanh.com/dl/docs/custommods/7904mod721K.pdf Custom Mod 721K (1972) Single shot readout and/or grat illumination] | ||
</small> | </small> | ||
}} | }} | ||
The '''Tektronix 7904''' is a 500 MHz, non-storage 7000-series oscilloscope mainframe with four bays. | The '''Tektronix 7904''' is a 500 MHz, non-storage 7000-series oscilloscope mainframe with four bays. | ||
It accepts two [[7000-series_plug-ins#Vertical plug-ins|7000-series vertical plug-ins]] and two [[7000-series_plug-ins#Horizontal plug-ins|7000-series horizontal plug-ins]]. | |||
It was introduced in late 1971/early 1972 (Note 1). | |||
The successor model 7904A was introduced in 1984. | |||
There is also a rack-mount version, the [[R7903]], albeit with only one horizontal bay. | |||
Performance is largely determined by the plug-ins. | Performance is largely determined by the plug-ins. | ||
The [[7A19]] vertical amplifier and [[7B92]] time base were introduced along with the 7904 to match the 500 MHz system bandwidth. | |||
Design Staff of 7904 Project (from July 1971 Tekscope): | |||
<blockquote>[[Val Garuts]] was project manager and developed the large signal amplifier circuit used in the horizontal and Z-axis amplifiers. [[Thor Hallen]] did the [[7A19]] plug-in and the vertical amplifier, and [[John McCormick]] the horizontal. The trigger and time base ([[7B92]] plug-in) were done by [[Les Larson]] and [[Bill DeVey]]. [[Bill Peek]] worked on the Z-axis amplifier and auto-focus, with [[Hans Springer]] doing the mainframe interface and channel switching. [[Joe Burger]]'s work on the power supply, coupled with [[Joel Swanno]]’s efforts in mechanical design, reduced the weight to only 30 pounds. [[Ken Hawken]] did the fine job on the CRT. </blockquote> | |||
{{BeginSpecs}} | {{BeginSpecs}} | ||
{{Spec | Bandwidth | 500 MHz }} | {{Spec | Bandwidth | 500 MHz }} | ||
{{Spec | Fastest calibrated sweep | 500 ps/Div (with [[7B92A]], other time bases "uncalibrated for first 60 ns") }} | {{Spec | Fastest calibrated sweep | 500 ps/Div (with [[7B92A]], other time bases "uncalibrated for first 60 ns") }} | ||
{{Spec | Calibrator | DC, square wave (1 kHz or ½ B Sweep gate), 4 mV to 40 V in decade steps (2/20/200/400 mV into 50 Ω); 40 mA current loop }} | |||
{{Spec | Vertical modes | Left / Alt / Add / Chop / Right }} | |||
{{Spec | Horizontal modes | A / Alt / Chop / B }} | |||
{{Spec | Trigger Source | Left / Vert Mode / Right }} | |||
{{Spec | Inputs | | |||
* Z Axis (15 V<sub>p-p</sub>) | |||
}} | |||
{{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 | CRT | | |||
* Standard: (8×10 Div @ 1 cm), P31 (green) [[154-0644-05]] or P11 (blue) [[154-0644-09]] | |||
* Option 4, high writing speed: (8×10 Div @ 0.5 cm) , P31 (green) [[154-0661-05]] or P11 (blue) [[154-0661-09]] | |||
}} | |||
{{Spec | Acceleration voltage | 24 kV (+21 / -3 kV) }} | {{Spec | Acceleration voltage | 24 kV (+21 / -3 kV) }} | ||
{{Spec | | {{Spec | Power | 90−132 V or 180−264 V, 48−440 Hz, 190 W max. }} | ||
{{Spec | Weight | 13.5 kg (30 lbs) }} | {{Spec | Weight | 13.5 kg (30 lbs) }} | ||
{{Spec | | {{Spec | Size | | ||
: 34.2 cm × 30.5 cm × 69.5 cm (H×W×L) | |||
: (13.5 in x 12.0 in x 23.8 in) | |||
}} | }} | ||
{{EndSpecs}} | {{EndSpecs}} | ||
==Links== | |||
* [[Media:A subnanosecond realtime oscilloscope garuts hallen.pdf|A Subnanosecond Realtime Oscilloscope]], [[Media:Tekscope 1971 V3 N4 Jul 1971.pdf | Tekscope Vol.3 No.4, July 1971]] | |||
* [https://lazyelectrons.wordpress.com/2018/11/24/tektronix-7904-oscilloscope-power-supply-repair/ 7904 Repair with Video] | |||
* [http://amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_mainframe/7904.htm Tek 7904] / [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] | |||
* [http://www.barrytech.com/tektronix/tek7000/tek7904.html Tek 7904] / [http://www.barrytech.com/tektronix/tek7000/tek7904a.html 7904A] @ barrytech.com* | |||
* [https://www.youtube.com/watch?v=GQn0EqW-u74 Tektronix 7904 lab check in and LED MOD] by Zenwizard Studios @ YouTube | |||
{{Documents|Link=7904}} | |||
{{Documents|Link=7904A}} | |||
===7904A differences=== | ===7904A differences=== | ||
The 7904A re- | The 7904A ([[:Category:Introduced in 1984 |introduced in 1984]]) borrows heavily from the previously introduced [[7104]] in terms of front panel layout, mechanical design, and electronics, re-implementing the vertical amplifier using Hypcon-packaged amplifier chips such as the [[155-0178-00]]. | ||
The 7904 had | 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). | |||
===Options=== | ===Options=== | ||
<div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> | <div style="column-count:4;-moz-column-count:4;-webkit-column-count:4"> | ||
* Opt.1: deletes read out system | |||
* Opt.2: X-Y delay compensation network | * Opt.2: X-Y delay compensation network | ||
* Opt.3: Extra EMI shielding | * Opt.3: Extra EMI shielding | ||
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==Operation== | ==Operation== | ||
The 7904 has many modes of operation. | |||
One mode is called "Independent-Pairs Display" in the manual, where the input to the left vertical plug-in is displayed using the B horizontal time-base plug-in, | |||
and the input to the right vertical plug-in is displayed using the A horizontal time-base plug-in. | |||
This resembles the trace-slaving "ALT" mode that is produced by an [[1A4]] in a [[547]]. Many other modes are available. | |||
It is possible to put vertical plug-ins in the horizontal slots for X-Y operation. | |||
It is even possible to put a horizontal plug-in in one of the vertical slots to produce a raster scan. | |||
A special plug-in, the [[7A21N]], provides direct access to the deflection plates up to 1 GHz at an uncalibrated sensitivity of 4 V/Div. | |||
This plugin requires modifications to the mainframe to bypass the Y output amplifier (thus disabling readout and the other vertical plugin bay). | |||
A | A rear-panel [[7904 remote control connector| remote control connector]] has connections for single-sweep ready lamps, a reset button, and readout control. | ||
==Internals== | ==Internals== | ||
The 7904 | The 7904(A) 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]]. | |||
===7904=== | |||
The 7904 uses a switch-mode power supply and has no fan. | |||
[[Thor Hallen]] designed the main vertical amplifier and the [[7A19]] plugin (Note 1). | |||
It used bridged T coils and the "[[ft doubler|f<sub>t</sub> doubler]]" circuit patented by [[Carl Battjes]] to achieve its bandwidth. | |||
The | The 7904 makes extensive use of custom integrated circuits and hybrid circuits, inter alia, the [[155-0064-00]] 470-ps output amplifier, | ||
[[155-0022-00]] analog multiplexer for channel switching, [[155-0059-00]] HF amplifier, | |||
[[155-0095-01]] and [[155-0095-03]] differential HF amplifiers, and [[155-0067-02]] SMPS controller. | |||
The | Early 7904 have issues with horizontal aberrations for sweep rates of 1 ns/Div or faster. After discovery of the issue modification kits that replace the horizontal amplifier were offered. For more information see the table below and the [[Media:Tek 067-0657-00 with schematics.pdf|manual]] of the [[067-0657-00|067-0657-00 Normalized Ramp Generator]] that was used to investigate and rectify this issue. | ||
{| class="wikitable" | |||
|- | |||
! Serial Number | |||
! A9 Horizontal Amp. | |||
! Issue | |||
! Modification Kit | |||
|- | |||
|B010000-B081987 | |||
||670-1632-00 | |||
|Fully calibrated sweeps for rates of 1 ns/Div or faster requires a dedicated [[7B92]] (non A!) and the two units to be calibrated as a system. | |||
|050-0636-01 | |||
|- | |||
|B081988-B219999 | |||
||670-1632-01 | |||
|Can be calibrated to either work with magnifier timebases ([[7B70]],[[7B80]]), or alternatively non-magnifying time bases ([[7B92A]]), but not both. | |||
|040-0791-00 | |||
|- | |||
|B220000 and above | |||
|670-1632-02/03 | |||
|None - fully compatible with all timebases and all sweep rates. | |||
|− | |||
|} | |||
===7904A=== | |||
The 7904A is a complete redesign and uses the [[155-0173-05]], [[155-0175-05]] and [[155-0178-05]] amplifiers developed for the [[7104]]. A fan is added at the rear switch mode power supply. | |||
==Prices== | ==Prices== | ||
Line 100: | Line 183: | ||
|align=right| $12,750 | |align=right| $12,750 | ||
|- | |- | ||
! | ! In 2022 Dollars | ||
|align=right| $ | |align=right| $19,500 | ||
|align=right| $ | |align=right| $20,300 | ||
|align=right| $ | |align=right| $21,400 | ||
|align=right| $ | |align=right| $23,800 | ||
|align=right| $ | |align=right| $27,400 | ||
|- | |- | ||
!rowspan=2| Mainframe with [[7A19]],<br />7A19 Opt. 04, [[7B92]] | !rowspan=2| Mainframe with [[7A19]],<br />7A19 Opt. 04, [[7B92]] | ||
Line 115: | Line 198: | ||
|align=right| $24,190 | |align=right| $24,190 | ||
|- | |- | ||
! | ! In 2022 Dollars | ||
|align=right| $ | |align=right| $37,000 | ||
|align=right| $ | |align=right| $38,400 | ||
|align=right| $ | |align=right| $41,000 | ||
|align=right| $ | |align=right| $47,200 | ||
|align=right| $ | |align=right| $52,000 | ||
|} | |} | ||
==Notes== | ==Notes== | ||
# See [[7A11]] and [[John Addis]], ''Good Engineering and Fast Vertical Amplifiers'', in Jim Williams (Ed.), ''Analog Circuit Design: Art, Science and Personalities'' (1991), p.114, and [ | # See [[7A11]] and [[John Addis]], ''Good Engineering and Fast Vertical Amplifiers'', in [[Jim Williams]] (Ed.), ''Analog Circuit Design: Art, Science and Personalities'' (1991), p.114, and [[Media:Tektronix_New_Products_March_1972.pdf|Tektronix New Products 1972]] brochure. | ||
==Pictures== | ==Pictures== | ||
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===7904 non-A=== | ===7904 non-A=== | ||
<gallery> | <gallery> | ||
Tek-7904-front.jpg | 7904 (non-A) front | |||
Tek 7904 rear.jpg | 7904 rear | |||
7904-left.jpg | Left side. Left top: Vertical amplifier; left bottom: switch-mode power supply; right center: delay line; right bottom: plug-in bays | |||
7904-right.jpg | Right side. Top left: calibrator; bottom left: plug-in bays; top center: [[7000 series readout system|readout board]]; top right: Z amplifier | |||
7904-right-front.jpg | Right side detail. Left: calibrator; right: readout. | |||
7904 interface 1.jpg|Plug-in backplane board front (left trigger selector piggyback board removed) | |||
Tek7904-trig-selector.jpg | B Trigger selector piggyback board (A6) | |||
Tek7904-vertical-interface.jpg | Vertical interface piggyback board (A7). The two [[155-0095-03]] amplifiers (large metal cans) are used to select the signal from one vertical plug-in bay, and drive the delay line. | |||
7904 interface 2.jpg|Plug-in backplane board rear | |||
Tek7904-backplane-bottom.jpg | Backplane board sandwich seen from below | |||
7904-x-amp.jpg | Horizontal (X) amplifier board (late >B220000) | |||
7904-y-amp.jpg | Vertical (Y) amplifier board | |||
7904-z-amp.jpg | Z amplifier board | |||
7904-controls.jpg | front-panel controls | |||
7904_block.gif|7904 block diagram | |||
Tek7904-7a19-7b92a-1010mhz-hfsync.jpg | A 7B92A (B098xxx) displaying a 1.01 GHz sine in HF Sync mode ([[7904]] mainframe, [[7A19]] amplifier). | |||
</gallery> | </gallery> | ||
====Power Supply==== | ====Power Supply==== | ||
<gallery> | <gallery> | ||
7904-psu-internal.jpg | 7904 switchmode power supply, covers removed | |||
7904-psu-right.jpg | View from right (as seen from front of instrument) | |||
7904-psu-primary.jpg | Primary side circuit board | |||
7904-psu-primary-caps.jpg | Primary side capacitors | |||
7904-psu-transformer.jpg | Detail view of transformer from the side | |||
Tek_7904_SMPS-xformer.jpeg| Switching transformer | |||
7904-psu-rectifier.jpg | Secondary side rectifier board | |||
7904-psu-regulator.jpg | Secondary side post-regulator | |||
Tek_7904_SMPS-HV-Block.jpeg| HV block, multiplier | |||
</gallery> | </gallery> | ||
Line 168: | Line 247: | ||
<gallery> | <gallery> | ||
7904a-front.jpg |7904A | 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 lvps1.png|7904A Low-voltage Power Supply Schematic | ||
7904a-h-v.jpg | 7904A Horizontal and vertical amplifiers | 7904a-h-v.jpg | 7904A Horizontal and vertical amplifiers | ||
</gallery> | </gallery> | ||
==Parts== | |||
{{Parts|7904}} | |||
{{Parts|7904A}} | |||
{{Custom ICs|7000 series readout system}} | |||
[[Category:7000 series non-storage mainframes]] | [[Category:7000 series non-storage mainframes]] |
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