7A13: Difference between revisions

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|designers=Bill DeVey
|designers=Bill DeVey
|manuals=
|manuals=
* [[Media:070-0978-00.pdf|Tektronix 7A13 Manual (sn < B200000)]] (PDF, OCR) / [http://bama.edebris.com/download/tek/7a13/tek-7a13_early.pdf @ BAMA] (PDF)
* [[Media:070-0978-00.pdf|Tektronix 7A13 Manual (sn < B040000)]] (OCR, color, split schematics)
* [[Media:070-1948-00.pdf|Tektronix 7A13 Instruction Manual (SN B200000-up)]] (PDF, OCR) / [http://bama.edebris.com/download/tek/7a13/tek-7a13_late.pdf @ BAMA] (PDF)
* [[Media:Tek-7a13 early.pdf|Tektronix 7A13 Manual (sn < B040000)]] (OCR, grayscale, whole schematics)
* [[Media:070-1113-00.pdf|Tektronix 7A13 Instruction Manual (SN B0400000-up)]]
* [[Media:070-1113-00.pdf|Tektronix 7A13 Instruction Manual (SN B040000-B199999)]]
* [[Media:TB-9-6625-2132-35.pdf|TB 9-6625-2132-35 Calibration Procedure for AM-6881/U (7A13) and AM-6786/U (7A22)]] (PDF, 2M)
* [[Media:070-1948-00.pdf|Tektronix 7A13 Instruction Manual (SN B200000-up)]] (OCR)  
* [[Media:7A13 B250000-up Manual Change.pdf|Supplement for 070-1948-00: errata plus LD121A mod]]
* [[Media:7A13 B200000-up Manual Change.pdf|Another Supplement for 070-1948-00]]
* [[Media:TB-9-6625-2132-35.pdf|TB 9-6625-2132-35 Calibration Procedure for AM-6881/U (7A13) and AM-6786/U (7A22)]]
}}
}}
The '''Tektronix 7A13''' is a "differential comparator" vertical plug-in for [[7000-series scopes]], i.e. a fast differential amplifier with adjustable DC offset.   
The '''Tektronix 7A13''' is a "differential comparator" vertical plug-in for [[7000-series scopes]], i.e. a fast differential amplifier with adjustable DC offset.   
It is one of the first 7000 series plugins.
It is one of the first 7000 series plugins.
It was designed by [[Bill DeVey]] and released along with the [[Introduction to the 7000-Series|first 7000-series scopes]] in 1969/1970, and was made until the 7000 series was retired in 1992.
It was designed by [[Bill DeVey]] and released along with the [[Introduction to the 7000-Series|first 7000-series scopes]] in 1969/1970, and was made until the 7000 series was retired in 1992.
The 7A13 was known internally as the XA3 until just before release when the final nomenclature was determined.


==Operation==
==Operation==
Older versions display the comparison (offset) voltage through a mechanical dial, newer versions (from 1976 on) through an LED panel meter.  
Older versions display the comparison (offset) voltage through a mechanical dial.
Newer versions (from 1976 on) display the comparison voltage on an LED panel meter.  
In addition, this voltage is brought out through a front panel connector so it can be measured externally.
In addition, this voltage is brought out through a front panel connector so it can be measured externally.


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{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Bandwidth | 100 MHz (in 7700 or faster mainframes) }}
{{Spec | Bandwidth | 100 MHz (in 7700 or faster mainframes) }}
{{Spec | Rise time | 3.5 ns }}
{{Spec | Risetime | 3.5 ns }}
{{Spec | Deflection factor | 1 mV/Div – 5 V/Div (1–2–5 sequence) }}
{{Spec | Deflection | 1 mV/Div – 5 V/Div (1–2–5 sequence) }}
{{Spec | Common-mode range | at least +10 V / −10 V from 1 mV/Div to 5 mV/Div, +100 V / −100 V from 10 mV/Div to 50 mV/Div, +500 V / −500 V from 100 mV/Div to 5 V/Div }}
{{Spec | Common-mode range | at least ±10 V from 1 mV/Div to 5 mV/Div, ±100 V from 10 mV/Div to 50 mV/Div, ±500 V from 100 mV/Div to 5 V/Div }}
{{Spec | Overdrive recovery | to within 2 mV in 1µs (at 1 mV/Div) }}
{{Spec | Overdrive recovery | to within 2 mV in 1µs (at 1 mV/Div) }}
{{Spec | CMRR | ≥10,000:1 for 10 V<sub>p-p</sub> or less, 100 kHz to 1 MHz, decreasing to 500:1 at 10 MHz with 1 V<sub>p-p</sub>, 200:1 at 20 MHz with 1 V<sub>p-p</sub> }}
{{Spec | CMRR | ≥10,000:1 for 10 V<sub>p-p</sub> or less, 100 kHz to 1 MHz, decreasing to 500:1 at 10 MHz with 1 V<sub>p-p</sub>, 200:1 at 20 MHz with 1 V<sub>p-p</sub> }}
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{{Spec | Warmup time | 5 minutes for short-term measurements, 1 hour for best stability }}
{{Spec | Warmup time | 5 minutes for short-term measurements, 1 hour for best stability }}
{{EndSpecs}}
{{EndSpecs}}
==Links==
* [https://www.youtube.com/watch?v=IqE_LNXnPyo Tektronix 7A13 Repair and Alignment] by Zenwizard Studios @ YouTube
{{Documents|Link=7A13}}
{{PatentLinks|7A13}}


==Power Consumption==
==Power Consumption==
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which is implemented through small light bulbs above the dial with plastic light guides to make the decimal point appear between the digits.
which is implemented through small light bulbs above the dial with plastic light guides to make the decimal point appear between the digits.
In contrast to the [[back-lit switches]], the decimal point lamps are supplied from logic +5 V
In contrast to the [[back-lit switches]], the decimal point lamps are supplied from logic +5 V
so they work also in mainframes without switch light supplies, e.g. the 76x3s.
so they also work in mainframes without switch light supplies, e.g. the 76x3s.


In the newer version, the zener-derived reference voltage is always positive.
In the newer version, the zener-derived reference voltage is always positive.
A 10-turn pot for coarse selection combines with a single-turn pot for fine control.
A 10-turn pot for coarse selection combines with a single-turn pot for fine control.
The resultant voltage is displayed on a 4-digit simplified DVM built around a [[Fairchild 3814]] 4½ digit DVM controller.
The resultant voltage is displayed on a 4-digit simplified DVM built around a [[Fairchild 3814]] 4½ digit DVM controller.
(S/N B250000+ switched to a [[Siliconix LD122]]/[[Siliconix LD121A|LD121A]] chipset.)
For negative values of V<sub>C</sub>, an opamp polarity inverter circuit is switched in.
For negative values of V<sub>C</sub>, an opamp polarity inverter circuit is switched in.


Line 71: Line 82:
===Repair issues===
===Repair issues===
The 7A13 uses twelve [[miniature relays]] similar to those used in the [[7A11]].  These are very rare.
The 7A13 uses twelve [[miniature relays]] similar to those used in the [[7A11]].  These are very rare.
The [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_amplifier/amplifier_7A11.htm 7A11 repair report at amplifier.cd]  
The [https://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_amplifier/amplifier_7A11.htm 7A11 repair report at amplifier.cd]  
describes a possible replacement with a modern component. See also the IK1ZYW link below.
describes a possible replacement with a modern component. See also the IK1ZYW link below.


Line 83: Line 94:


==Links==
==Links==
 
* [https://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_amplifier/amplifier_7A13.htm Tek 7A13 @ amplifier.cd]
* [[Media:Tekscope 1970 V2 N5 Oct 1970.pdf|Amplitude measurements to better than 1%.  Tekscope Vol. 2 No. 5, October 1970]]
* [https://www.radiomuseum.org/r/tektronix_differential_comparator_unit_7a13.html Tek 7A13 @ radiomuseum.org]
* [http://www.amplifier.cd/Test_Equipment/Tektronix/Tektronix_7000_series_amplifier/amplifier_7A13.htm Tek 7A13 @ amplifier.cd]
* [https://ik1zyw.blogspot.com/2007/09/tektronix-7a13-broken-relays.html Tek 7A13 broken relays @ IK1ZYW Labs]
* [http://www.barrytech.com/tektronix/tek7000/tek7a13.html Tek 7A13 @ barrytech.com]
* [https://www.pa4tim.nl/?p=5755 Repairing 7A13 relays @ PA4TIM] (how to take relays apart, inside photos)
* [http://www.radiomuseum.org/r/tektronix_differential_comparator_unit_7a13.html Tek 7A13 @ radiomuseum.org]
* [https://www.youtube.com/watch?v=IqE_LNXnPyo Tektronix 7A13 Repair and Alignment] by Zenwizard Studios @ YouTube
* [http://ik1zyw.blogspot.com/2007/09/tektronix-7a13-broken-relays.html Tek 7A13 broken relays @ IK1ZYW Labs]
* [http://www.pa4tim.nl/?p=5755 Repairing 7A13 relays @ PA4TIM] (how to take relays apart, inside photos)


==Pictures==
==Pictures==
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Tek 7a13 step response.jpg|Step response of 7A13 using [[S-52]] and [[7704A]]. Overall rise time is 3.3 ns.
Tek 7a13 step response.jpg|Step response of 7A13 using [[S-52]] and [[7704A]]. Overall rise time is 3.3 ns.
</gallery>
</gallery>
==Components==
{{Parts|7A13}}


[[Category:7000 series vertical plugins]]
[[Category:7000 series vertical plugins]]
[[Category:Differential amplifiers]]
[[Category:Differential amplifiers]]

Latest revision as of 03:59, 19 September 2024

Tektronix 7A13
100 MHz Differential Comparator
7A13 front panel (older version with mechanical voltage display)

Compatible with 7000-series scopes

Produced from 1969 to 1992

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix 7A13 is a "differential comparator" vertical plug-in for 7000-series scopes, i.e. a fast differential amplifier with adjustable DC offset. It is one of the first 7000 series plugins. It was designed by Bill DeVey and released along with the first 7000-series scopes in 1969/1970, and was made until the 7000 series was retired in 1992.

The 7A13 was known internally as the XA3 until just before release when the final nomenclature was determined.

Operation

Older versions display the comparison (offset) voltage through a mechanical dial. Newer versions (from 1976 on) display the comparison voltage on an LED panel meter. In addition, this voltage is brought out through a front panel connector so it can be measured externally.

In differential mode, a ±10 V common mode signal can be present at the inputs without attenuation. Either input can be switched to the comparison voltage, which is settable to four digits by a 10-step switch and a 10-turn potentiometer. In this comparator mode, the offset range is effectively 10,000 divisions.

On the 1 mV/Div to 50 mV/Div ranges, the gate resistors can be disabled by an internal switch, raising DC input impedance to "approximately infinite" (as indicated by a front panel lamp).

Key Specifications

Bandwidth 100 MHz (in 7700 or faster mainframes)
Risetime 3.5 ns
Deflection 1 mV/Div – 5 V/Div (1–2–5 sequence)
Common-mode range at least ±10 V from 1 mV/Div to 5 mV/Div, ±100 V from 10 mV/Div to 50 mV/Div, ±500 V from 100 mV/Div to 5 V/Div
Overdrive recovery to within 2 mV in 1µs (at 1 mV/Div)
CMRR ≥10,000:1 for 10 Vp-p or less, 100 kHz to 1 MHz, decreasing to 500:1 at 10 MHz with 1 Vp-p, 200:1 at 20 MHz with 1 Vp-p
Input impedance 1 MΩ // 20 pF
Comparison voltage −10 V to +10 V
Vc reading accuracy

Mechanical version: 0.1% of reading + 5 mV
DVM version: 0.1% of reading + 3 mV

Warmup time 5 minutes for short-term measurements, 1 hour for best stability

Links

Documents Referencing 7A13

Document Class Title Authors Year Links
Tekscope 1969 V1 N5 Oct 1969.pdf Article Introducing the New Generation 1969 7000-series scopes • 7504 • 7704 • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7S11 • 7M11 • 7B50 • 7B51 • 7B70 • 7B71 • 7T11 • R5030 • 7000 series readout system • Miniature relays • Cam switches • Industrial Design • T7500 • T7700 • P6052 • P6053 • C-50 • C-51 • 204-2
Tekscope 1969 V1 N6 Dec 1969.pdf Article A New Logic for Oscilloscope Displays 1969 7000-series scopes • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A22 • 7B50 • 7B51 • 7B70 • 7B71 • 7S11 • 7T11 • 7504 • 7704
Tekscope 1970 V2 N5 Oct 1970.pdf Article Amplitude Measurement to Better Than 1% 1970 1S1 • 7503 • 7A13 • 1A5 • W • 3A7
Tekscope 1972 V4 N5 Sep 1972.pdf Article A Practical Approach to Differential Amplifiers and Measurements Fred Beckett 1972 112 • 11A33 • 1A5 • 1A6 • 1A7 • 1A7A • 26A2 • 3A9 • 5A22N • 7A13 • 7A22 • AM502 • D • E • G • P6055 • P6046 • W • Z
Tekscope 1972 V4 N6 Nov 1972.pdf Article Differential Amplifiers and Measurements, Part 2 Fred Beckett 1972 112 • 11A33 • 1A5 • 1A6 • 1A7 • 1A7A • 26A2 • 3A9 • 5A22N • 7A13 • 7A22 • AM502 • D • E • G • P6055 • P6046 • W • Z
7000 series brochure March 1973.pdf Brochure 7000 series brochure, March 1973 1973 7A11 • 7A12 • 7A13 • 7A14 • 7A15A • 7A16A • 7A17 • 7A18 • 7A19 • 7A21N • 7A22 • 7B50 • 7B53A • 7B70 • 7B71 • 7B92 • 7CT1N • 7D11 • 7D13 • 7D14 • 7D15 • 7M11 • 7L12 • 7S11 • 7S12 • 7T11 • 7704A • R7704 • 7904 • R7903 • 7603 • R7603 • 7403N • R7403N • 7313 • R7313 • 7613 • R7613 • 7623 • R7623 • P7001

Patents that may apply to 7A13

Page Title Inventors Filing date Grant date Links
Patent US 3584174A Push-button switch apparatus having cam actuated switch contacts and selective illumination means Tony Sprando • Peter S Winkelmann 1969-06-09 1971-06-08 Back-lit switches • 7A11 • 7A12 • 7A13 • 7A14 • 7A16 • 7A16P • 7A22 • 7A42 • 7B42N • 7B50 • 7B51 • 7B52 • 7B53A • 7B70 • 7B71 • 7B92 • 7B92A • 7D10 • 7D11 • 7D12 • 7D114 • 7D15 • 7D20 • 7F10 • 7L5 • 7L12 • 7L13 • 7L14 • 7L18 • 7M13 • 7S11 • 7S12 • 7T11 • 067-0587-00 • 067-0587-01 • 067-0587-02 • 067-0587-10

Power Consumption

The power consumption of a 7A13 was measured to be:

  • +50 V: 75 mA
  • −50 V: 66 mA
  • +15 V: 238 mA
  • −15 V: 204 mA
  • +5 V (logic): 279 mA
  • +5 V (lights): 228 mA

Internals

In the older version, the comparison voltage is generated from a precision zener supplied from either positive or negative 50 V rail, followed by a 10-step switched divider made of 0.1% resistors to select the first digit. For the lower three digits, a ten-turn potentiometer with a mechanical digital readout is used. The V/Div switch changes the decimal point on the readout, which is implemented through small light bulbs above the dial with plastic light guides to make the decimal point appear between the digits. In contrast to the back-lit switches, the decimal point lamps are supplied from logic +5 V so they also work in mainframes without switch light supplies, e.g. the 76x3s.

In the newer version, the zener-derived reference voltage is always positive. A 10-turn pot for coarse selection combines with a single-turn pot for fine control. The resultant voltage is displayed on a 4-digit simplified DVM built around a Fairchild 3814 4½ digit DVM controller. (S/N B250000+ switched to a Siliconix LD122/LD121A chipset.) For negative values of VC, an opamp polarity inverter circuit is switched in.

The 7A13 uses the ±50 V supplies provided by the mainframe.

Repair issues

The 7A13 uses twelve miniature relays similar to those used in the 7A11. These are very rare. The 7A11 repair report at amplifier.cd describes a possible replacement with a modern component. See also the IK1ZYW link below.

Early 7A13 plug-ins were made with a mechanical counter for reading out the comparison voltage. The plastic gears in this counter don't age well. The plug-in can still be used when the counter fails, by using an external voltmeter to monitor the comparison voltage, Vc.

Later 7A13 plug-ins use an LED readout instead of the mechanical counter. The LED readout is much less problematic.

Links

Pictures

Older version (1970-1975, mechanical meter)

  • 7A13 older version, front view

    7A13 older version, front view

  • 7A13, left side

    7A13, left side

  • 7A13, right side

    7A13, right side

  • closeup of mechanical VC display in operation

    closeup of mechanical VC display in operation

  • Three light bulbs above the digit dials for decimal point indication

    Three light bulbs above the digit dials for decimal point indication

  • Gear mechanism

    Gear mechanism

  • Gear mechanism. If the leftmost display digit is misaligned with respect to the switch position, the left pair of bevel gears seen here need to be rotated relatively to each other.

    Gear mechanism. If the leftmost display digit is misaligned with respect to the switch position, the left pair of bevel gears seen here need to be rotated relatively to each other.

Newer version (1976-1992, LED meter)

  • 7A13 newer version, front view

    7A13 newer version, front view

  • 7A13 newer version, left interior

    7A13 newer version, left interior

  • 7A13 newer version, right interior (some non-original relays)

    7A13 newer version, right interior (some non-original relays)

  • Later version of 7A13

    Later version of 7A13

  • Later version of 7A13

    Later version of 7A13

  • Later version of 7A13

    Later version of 7A13

  • Later version of 7A13

    Later version of 7A13

  • Later version of 7A13

    Later version of 7A13

  • Later version of 7A13

    Later version of 7A13

  • Later version of 7A13

    Later version of 7A13

  • Step response of 7A13 using S-52 and 7704A. Overall rise time is 3.3 ns.

    Step response of 7A13 using S-52 and 7704A. Overall rise time is 3.3 ns.

Components

Some Parts Used in the 7A13

Part Part Number(s) Class Description Used in
148-0034-00 148-0034-00 Discrete component miniature DPDT relay 5A48 • 7A11 • 7A13 • 7A14 • 7B70 • 7B71 • 7503 • 7904 • 7904A
148-0035-00 148-0035-00 Discrete component miniature SPDT relay 7A13 • 7A14 • 7B70 • 7B71
148-0050-00 148-0050-00 Discrete component miniature SPDT relay 7A13
148-0054-00 148-0054-00 Discrete component miniature SPDT+SPST relay 7A13
148-0055-00 148-0055-00 Discrete component miniature SPDT+SPST relay 7A13
Fairchild 3814 156-0306-00 Monolithic integrated circuit 4½ digit dual-slope DVM controller 7A13 • 7L13 • 7L18 • DM501
Siliconix LD121A 156-1305-00 Monolithic integrated circuit 4½ digit integrating ADC (digital section) 7A13 • DM501A
Siliconix LD122 156-2205-00 Monolithic integrated circuit 4½ digit integrating ADC (analog section) 7A13
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