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The 7104 is a 1GHz mainframe that takes [[7000-series plug-ins]], two vertical and two horizontal.
{{Oscilloscope Sidebar
The scope employs a [[micro-channel plate]] CRT design to get good screen intensity at high sweep speeds with moderate acceleration voltage.
|manufacturer=Tektronix
|series=7000-series scopes
|model=7104
|image=Tek7104-front.jpg
|caption=Tektronix 7104, front view
|introduced=1978
|discontinued=1990
|summary=1 GHz mainframe with MCP CRT
|designers=Val Garuts;Gene Andrews;Hans Springer;John Addis;Wink Gross;Art Metz;Aris Silzars;Conrad Odenthal;Dave Morgan;
|manuals=
* [[Media:070-2314-00.pdf|Tektronix 7104 Manual with Options]] (OCR)
* [[Media:7104_maintenance.pdf | 7104 maintenance - Tek-internal introduction for technicians]]
''Other Information''
* [[Media:Dennis Tillman 7104-7854 SMPS Dummy Load.pdf | Dummy load for troubleshooting 7854 and 7104 SMPS (Dennis Tillman) ]]
}}
The '''Tektronix 7104''' is a 1 GHz, non-storage 7000-series oscilloscope mainframe that takes 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 1978. There is also a rack-mount version, the [[R7103]], albeit with only one horizontal bay.


* [http://bama.edebris.com/download/tek/7104/tek-7104.pdf Tektronix 7104 Manual (PDF)]
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.
* [http://www.vintagetek.org/wp-content/uploads/2011/10/7104-Springer-article-email-res.pdf Hans Springer Electronic Design article on 7104]
 
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&deg; 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.
 
{{BeginSpecs}}
{{Spec | Bandwidth | 1 GHz (with [[7A29]]) – rise time < 350 ps}}
{{Spec | Fastest calibrated sweep | 200 ps/Div (with [[7B10]]) }}
{{Spec | 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 }}
{{Spec | Y delay line | 51 ns (frequency compensated coax pair) }}
{{Spec | X-Y phase shift |
* base model: < 2&deg; from DC to 50 kHz
* Opt. 2: < 2&deg; from DC to 50 MHz (with a pair of [[7A19]] or [[7A29]], at least one of which has the variable delay option) }}
{{Spec | Acceleration voltage | 12.5 kV }}
{{Spec | 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 }}
{{Spec | Power consumption | 215 W }}
{{Spec | Dimensions | 345 mm (h) × 305 mm (w) × 592 mm (l) }}
{{Spec | Weight | 19.8 kg (43.6 lb) }}
{{Spec | Features |
* Readout
* 2 probe power connectors
}}
{{Spec | Options |
* Opt.02 – X-Y Horizontal Compensation
* Opt.03 – EMI modification
}}
{{EndSpecs}}
 
==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 should '''not''' be used with plug-ins that generate a slow continuous sweep, or vector graphics. This includes [[:Category:7000 series sampling plugins|sampling plug-ins]], [[:Category:7000 series spectrum analyzer plugins|spectrum analyzers]], [[:Category:7000 series logic analyzer plugins|logic analyzers]], and the [[7D20]] digitizer.''
 
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 [[Media:Tek7104-200ps-singleshot-sin1-1g.jpg|screen shot]]).
 
==Internals==
 
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 ([http://www.google.com/patents/US4132958 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.
 
==Prices==
<!-- http://www.usinflationcalculator.com/ -->
{| class="wikitable"
|-
! &nbsp;
! Year
! 1980
! 1984
! 1990
|-
!rowspan=2| Mainframe only
! Catalog price
|align=right| $14,400
|align=right| $21,380
|align=right| $29,995
|-
! In 2023 Dollars
|align=right| $53,700
|align=right| $63,200
|align=right| $70,500
|-
!rowspan=2| Mainframe with [[7A29]],<br />7A29 Opt. 04, [[7B15]], [[7B10]]
! Catalog price
|align=right| $21,730
|align=right| $31,875
|align=right| $44,510
|-
! In 2023 Dollars
|align=right| $81,000
|align=right| $94,200
|align=right| $104,600
|-
|}
 
==Links==
* Hans Springer's 1979 [https://vintagetek.org/breakthroughs-throughout-push-scope-to-1-ghz/ Electronic Design article on the 7104]
* [http://readingjimwilliams.blogspot.com/2011/08/scope-sunday-4.html Reading Jim Williams: Scope Sunday 4]
* [http://amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_mainframe/7104.htm Tek 7104 @ amplifier.cd]
* [http://www.barrytech.com/tektronix/tek7000/tek7104.html Tek 7104 @ barrytech.com]
* [https://web.archive.org/web/20110926020847/http://www.oregonlive.com/silicon-forest/index.ssf/2011/09/a_tektronix_oscilloscope_that.html A Tektronix oscilloscope that moved faster than light?] The Oregonian, 23 Sep 2011.  (Original no longer accessible, link via archive.org.)
* [http://www.radiomuseum.org/r/tektronix_oscilloscope_mainframe_7104.html Tektronix 7104 @ radiomuseum.org]
{{Documents|Link=7104}}
 
==Pictures==
 
<gallery>
Tek7104-front.jpg                            | 7104 front view (operating)
Tek7104-1.jpg                                | 7104 with camera mounting frame on cart
Tek 7104 front.jpg                          | Front with empty plug-in bays
Tek 7104 plugin bay.jpg                      | Plug-in bays
Tek7104-5.jpg                                | Rear view of 7104
Tek 7104 rear.jpg                            | Rear view of 7104 
Tek 7104 probe power.jpg                    | Probe power outlets
Tek 7104 crtlabel.jpg                        | CRT label
Tek 7104 crtlabel mono.jpg                  | CRT label
Tek 7104 crt circuit1.jpg                    | CRT Circuit
Tek 7104 crt circuit2.jpg                    | CRT Circuit
Tek 7104 front outputs brightened.jpg        | Front outputs
Tek 7104 readout circuit brightened.jpg      | Readout board
Tek 7104 right brightened.jpg                | Interior right side
Tek7104-hor-and-vert-amp.jpg                | 7104 horizontal (top) and vertical (bottom) output amplifiers
Tek 7104 vertamp brightened.jpg              | Vertical amplifier
Tek 7104 vertampclose brightened.jpg        | Vertical amplifier close-up
Tek 7104 finalvert brightened.jpg            | Vertical amplifier, final stage close-up
Tek 7104 vertcrtinterconnect brightened.jpg  | Vertical CRT interconnect
Tek 7104 horizamp.jpg                        | Horizontal amplifier
Tek-7104-horiz-out-and-term.jpg              | 7104 horizontal output amplifier, CRT connection and termination of distributed horizontal deflection plates
Tek 7104 rearright brightened.jpg            | Rear right (vertical channel switch board and mainframe interconnect)
Tek7104-vert-sw.jpg                          | 7104 vertical channel switch board
Tek 7104 channel switch.jpg                  | 7104 vertical channel switch board
Tek 7104 split.jpg                          | The upper half of the 7104 can be tilted upward for service. A metal support is included, like on the hood of a car.
</gallery>
 
===Measurements===
<gallery>
<gallery>
Image:7104 grain.jpg
Tek7104-ristetime-100hz.jpg          | Rise time measurement.  150 ps risetime pulse from [[067-0587-02]] at 100 Hz repetition rate.  Measured 240 ps (corrected for 150 ps fixture rise time: 190 ps = 1.8 GHz)
Image:Tek7104-1.jpg
Tek7104-ristetime-1000hz.jpg         | Rise time measurement as before, 1000 Hz repetition rate at same brightness settings.
Image:Tek7104-5.jpg
Tek7104-200ps-singleshot.jpg        | 7104 recording a single shot pulse (from [[067-0587-02]]) at 200 ps/Div.  Camera: Nikon D7000,  50 mm f/1.4, ISO 3200, 1/2 s.  CRT filter not removed.
File:Tek 7104 probe power.jpg
Tek7104-200ps-singleshot-sin1-1g.jpg | 7104 recording 1 GHz sine, ''single sweep'' at 500 ps/Div. Camera: Nikon D7000, 50 mm f/1.4, ISO 3200, 1/2 s manually released.  CRT filter not removed.  CRT amplification loss is evident around the center line.
Tek7104-superluminal-beam.jpg       |  [https://web.archive.org/web/20110926020847/http://www.oregonlive.com/silicon-forest/index.ssf/2011/09/a_tektronix_oscilloscope_that.html Faster-than-light] beam on 7104?  Using a [[067-0587-02]] calibration fixture at maximum amplitude produces this trace spanning 1.2 Div horizontally at 200 ps/Div and 8 Div vertically.  Trace length is (1.2² + 8²)<sup>½</sup> × 8.5 mm = 68.8 mm, travelled in 1.2 × 200 ps = 240 ps.  Apparent speed is therefore 68.8×10<sup>-3</sup> / 240×10<sup>-12</sup> m/s or 2.86×10<sup>8</sup> m/s.  95.6% c<sub>0</sub> - a '''very''' near miss ...
</gallery>
</gallery>
==Components==
{{Parts|7104}}
{{Custom ICs|7000 series readout system}}
[[Category:7000 series non-storage mainframes]]
[[Category:Micro-channel plate CRTs]]
Retrieved from "https://w140.com/tekwiki/wiki/Special:MobileDiff/7359...90517"