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7904: Difference between revisions
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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. | 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): | |||
* [[Val Garuts]], project manager and horizontal and Z-axis amplifiers | |||
* [[Thor Hallen]], vertical amplifier and [[7A19]] | |||
* [[John McCormick]], horizontal amplifier | |||
* [[Les Larson]] and [[Bill DeVey]], trigger and timebase ([[7B92]]) | |||
* [[Bill Peek]], Z-axis amplifier and autofocus | |||
* [[Hans Springer]], mainframe interface and channel switching | |||
* [[Joe Burger]], power supply | |||
* [[Joel Swanno]], mechanical design | |||
* [[Ken Hawken]], CRT | |||
{{BeginSpecs}} | {{BeginSpecs}} | ||
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The 7904A re-implements the vertical amplifier using Hypcon-packaged amplifier chips designed for the [[7104]], such as the [[155-0178-00]]. | The 7904A re-implements the vertical amplifier using Hypcon-packaged amplifier chips designed for the [[7104]], such as the [[155-0178-00]]. | ||
The 7904 had an elaborate 5-decade built-in calibrator with variable rate that was dropped from the 7904A. | The 7904 had an elaborate 5-decade built-in calibrator with variable rate that was dropped from the 7904A. The [[7904 remote control connector|rear remote control connector]] unique to the 7904 was dropped as well. | ||
In the 7904A, The Control Illumination switch moved to the rear panel, and the [[7000 series readout system|readout system]] | 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. | gained a pulsed mode in which it is synchronized with the sweep instead of interrupting the display at random times. | ||
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==Operation== | ==Operation== | ||
The 7904 has | 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, | 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. | and the input to the right vertical plug-in is displayed using the A horizontal time-base plug-in. | ||
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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. | 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). | This plugin requires modifications to the mainframe to bypass the Y output amplifier (thus disabling readout and the other vertical plugin bay). | ||
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== | ||
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[[Thor Hallen]] designed the main vertical amplifier and the [[7A19]] plugin (Note 1). | [[Thor Hallen]] designed the main vertical amplifier and the [[7A19]] plugin (Note 1). | ||
It used bridged T coils and the "[[ | It used bridged T coils and the "[[ft doubler|f<sub>t</sub> doubler]]" circuit patented by [[Carl Battjes]] to achieve its bandwidth. | ||
The 7904 makes extensive use of custom integrated circuits and hybrid circuits, inter alia, the [[155-0064-00]] 470-ps output amplifier, | The 7904 makes extensive use of custom integrated circuits and hybrid circuits, inter alia, the [[155-0064-00]] 470-ps output amplifier, | ||
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|align=right| $12,750 | |align=right| $12,750 | ||
|- | |- | ||
! | ! 2019 value | ||
|align=right| $ | |align=right| $17,640 | ||
|align=right| $ | |align=right| $18,320 | ||
|align=right| $ | |align=right| $19,330 | ||
|align=right| $ | |align=right| $21,550 | ||
|align=right| $ | |align=right| $24,800 | ||
|- | |- | ||
!rowspan=2| Mainframe with [[7A19]],<br />7A19 Opt. 04, [[7B92]] | !rowspan=2| Mainframe with [[7A19]],<br />7A19 Opt. 04, [[7B92]] | ||
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|align=right| $24,190 | |align=right| $24,190 | ||
|- | |- | ||
! | ! 2019 value | ||
|align=right| $ | |align=right| $33,450 | ||
|align=right| $ | |align=right| $34,690 | ||
|align=right| $ | |align=right| $37,070 | ||
|align=right| $ | |align=right| $42,630 | ||
|align=right| $ | |align=right| $47,050 | ||
|} | |} | ||
==Links== | ==Links== | ||
* [https://lazyelectrons.wordpress.com/2018/11/24/tektronix-7904-oscilloscope-power-supply-repair/ 7904 Repair with Video] | |||
* [[Media:Tekscope 1971 V3 N4 Jul 1971.pdf | Tekscope Vol. 3 No. 4, Jul 1971]] | * [[Media:Tekscope 1971 V3 N4 Jul 1971.pdf | Tekscope Vol. 3 No. 4, Jul 1971]] | ||
* [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 | * [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 | ||
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==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 [http://w140.com/tektronix_new_products_1972.pdf Tektronix New Products 1972] brochure. | # 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 [http://w140.com/tektronix_new_products_1972.pdf Tektronix New Products 1972] brochure. | ||
==Pictures== | ==Pictures== | ||
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<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 | ||