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The Tektronix 7A26 is a 200 MHz dual-trace vertical plug-in for 7000-series
{{Plugin Sidebar
scopes. The input impedance is 1 megohm in parallel with 20 pF. 
|manufacturer=Tektronix
Deflection factors go from 5 mV/div to 5 V/div. 
|series=7000-series scopes
There is a switch to limit the bandwidth to 20 MHz.
|type=7A26
|summary=200 MHz dual-channel amplifier
|image=Tek 7a26 front_lc.jpg
|caption=7A26 front panel
|introduced=1974
|discontinued=1991
|designers=Tom Rousseau
|manuals=
* [[Media:070-1484-00.pdf|7A26 Instruction Manual -00]]
* [[Media:070-1484-01.pdf|7A26 Instruction Manual -01 Rev. Oct 1982]] (OCR)
* [[Media:Tek_7A26_Anleitung_Deutsch.pdf|Tek7A26 Anleitung (Operators Manual, German)]] (OCR)
* [[Media:040-0785-01.pdf|7A26 Vertical amplifier replacement]]
* [http://bama.edebris.com/download/tek/7a26mod/Tek%207A26%20IC%20Mod.pdf Tektronix 7A26 IC Mod] @ BAMA
}}
The '''Tektronix 7A26''' is a 200 MHz dual-trace vertical plug-in for [[7000-series scopes]].  
Designed by [[Tom Rousseau]], it was the most successful 7000 series plug-in, with over 120,000 units produced.


* [http://bama.edebris.com/download/tek/7a26/tek-7a26.pdf Tektronix 7A26 Manual (PDF)]
The 75 MHz [[7A18]] and 400 MHz [[7A24]] share the same front panel layout and operation.
* [http://bama.edebris.com/download/tek/7a26mod/Tek%207A26%20IC%20Mod.pdf Tektronix 7A26 IC Mod (PDF)]
 
{{BeginSpecs}}
{{Spec | Bandwidth |200 MHz}}
{{Spec | Deflection | 5 mV/Div – 5 V/Div in 1−2−5 sequence }}
{{Spec | Input impedance | 1 MΩ // 22 pF }}
{{Spec | Features | Bandwidth limiting switch (20 MHz) }}
{{EndSpecs}}
 
==Internals==
 
Controls layout and internal construction is very similar to the 75 MHz [[7A18]]. 
Whereas the 7A18 is a discrete design, the 7A26 uses Tek-made differential amplifier ICs [[155-0078-00|155-0078-xx]].
 
The 7A26 does not use the ±50 V supplies provided by the mainframe.
 
==Repair issues==
The pins of the attenuator modules are connected to conductive traces on the ceramic substrate inside by low-temperature soldering, which can go bad.
Re-seating the module can temporarily restore the internal contact but will usually not fix the problem permanently.
Repair is possible by opening the click-locked lid and carefully re-soldering.
 
==Links==
 
* [https://vintagetek.org/100000-7a26-plug-in/ Tom Rousseau's Golden 100,000<sup>th</sup> 7A26]
* [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_amplifier/amplifier_7A26.htm Tek 7A26] @ amplifier.cd
* [http://www.barrytech.com/tektronix/tek7000/tek7a26.html Tek 7A26] @ barrytech.com
* [https://www.youtube.com/watch?v=7scgCL_Rl6E Tektronix 7A26 Restoration and Alignment] by Zenwizard Studios @ YouTube
 
==Pictures==
 
<gallery>
Tek 7a26 front_lc.jpg | Front panel
Tek-7a26-left.jpg    | left side
Tek-7a26-right.jpg    | right side
7a26-cowboy.png      | [[Tektronix Cartoons|Cartoon]] in schematic: [http://www.reprise.com/host/tektronix/humor/cowboy.asp The 7A26 Sharp Shooter]
</gallery>
 
{{Custom ICs|7A26}}
 
[[Category:7000 series vertical plugins]]

Revision as of 10:15, 21 January 2022

Tektronix 7A26
200 MHz dual-channel amplifier
7A26 front panel

Compatible with 7000-series scopes

Produced from 1974 to 1991

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix 7A26 is a 200 MHz dual-trace vertical plug-in for 7000-series scopes. Designed by Tom Rousseau, it was the most successful 7000 series plug-in, with over 120,000 units produced.

The 75 MHz 7A18 and 400 MHz 7A24 share the same front panel layout and operation.

Key Specifications

Bandwidth 200 MHz
Deflection 5 mV/Div – 5 V/Div in 1−2−5 sequence
Input impedance 1 MΩ // 22 pF
Features Bandwidth limiting switch (20 MHz)

Internals

Controls layout and internal construction is very similar to the 75 MHz 7A18. Whereas the 7A18 is a discrete design, the 7A26 uses Tek-made differential amplifier ICs 155-0078-xx.

The 7A26 does not use the ±50 V supplies provided by the mainframe.

Repair issues

The pins of the attenuator modules are connected to conductive traces on the ceramic substrate inside by low-temperature soldering, which can go bad. Re-seating the module can temporarily restore the internal contact but will usually not fix the problem permanently. Repair is possible by opening the click-locked lid and carefully re-soldering.

Links

Pictures

Custom ICs used in the 7A26

Page Model Part nos Description Designers Used in
155-0078-00 M084 155-0078-xx 155-0273-00 155-0274-00 broadband amplifier John Addis 464 465 466 468 475 475A 475M 485 7834 7844 7854 7904 R7903 R7912 7912AD 7912HB 7104 7A16A 7A16P 7A24 7A26 7A42 067-0587-01 067-0680-00 AM503 PG502 PG508 DC510 DC5010 FG5010