7A42: Difference between revisions

Latest revision as of 02:36, 12 February 2024

Tektronix 7A42

350 MHz four-channel logic triggered amplifier

Compatible with 7000-series scopes

Produced from 1984 to 1990

Manuals

7A42 Operator Manual (OCR)
7A42 Service Manual
- 070-4286-00 Volume 1 (OCR)
- 070-4654-00 Volume 2, Signature Analysis Tables (OCR)

ROM images

(All manuals in PDF format unless noted otherwise)

Manuals – Specifications – Links – Pictures

The Tektronix 7A42 is a four-channel 350 MHz plug-in for 7000-series scopes. It is a double-wide plug-in, with signal outputs and mainframe readout only using the left slot.

It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs. A fifth trace, "Trigger View", displays the trigger function output or external clock input.

There are two sets of conditions, A and B, that can be individually selected or paired in an "A then B" mode called nested triggering, where the occurrence of condition A arms the trigger and condition B causes the trigger to be generated. The trigger can be qualified by an external clock. A trigger filter control, variable from 0-300 ns, allows events shorter than the selected length to be suppressed. A TTL-level "reset" input will inhibit the trigger if active.

Selected by an internal jumper, either the trigger signal, or the "A then B" interval, is available on a front-panel trigger output. This can e.g. be routed to a counter for time measurement or event counting.

The input V/Div setting can only be seen in the mainframe's readout. There is a jumper to allow the readout to work in a 7854 mainframe. The trigger level is set digitally and shown on a 7-segment display.

Tektronix recommended the P6131, 300 MHz, 10 MΩ ×10 probe, and the P6230, 1.5 GHz, 450/50 Ω ×10, variable-offset probe for ECL circuits.

The 067-1155-99 calibration fixture is specific to the 7A42.

Key Specifications

Bandwidth	350 MHz
Deflection	0.1 / 0.2 / 0.5 V/Div (TTL mode) 20 / 50 / 100 mV/Div (ECL mode) each direct or through 10:1 probe always DC coupled
Input impedance	1 MΩ // 15 pF or 50 Ω
Max. input voltage	at 1 MΩ: 25 V (DC+peak AC) below 36 MHz, down to 3 V_AC at 300 MHz at 50 Ω: 5 V_RMS during any 1 ms interval
Trigger level	−1.27 to +1.28 V (TTL mode) in 10 mV steps −254 mV to +256 mV (ECL mode) in 2 mV steps (or ×10)
Hysteresis	40 mV (TTL), 8 mV (ECL) (or ×10)
Features	NiCd battery to preserve front-panel control status
Weight	2.8 kg / 6.2 lb

Links

Documents Referencing 7A42

Document	Class	Title	Authors	Year	Links
42W-5588.pdf	Application Note	Advanced Triggering Techniques	Roger Ensrud	1984	7A42 • 7D11 • 7D15

Internals

The 7A42's functions are controlled by an Intel 8085A microprocessor, with code in three 2764 EPROMs (a fourth ROM socket is unused). The front-panel pushbuttons are handled by an Intel 8279 keyboard controller.

Each of the four 119-1517-00 input attenuator modules contains five 148-0145-00 miniature bi-stable relay actuators. These have four long pins plugging in to the base board, driving two solenoids that move aa yoke which is held in the last active position by a permanent magnet. The yoke moves a pair of contact springs that directly short corresponding pads on the thick-film ceramic substrate. The relay coils are wired in a 4×5 matrix.

The 7A42 contains its own switch mode PSU, based on an SG3524 controller, that generates +5 V, −2 V and −5 V from the mainframe's ±50 V rails.

There is a NiCd backup battery that allows the unit to retain its last configuration.

A 555 timer implements a 15 ms "real-time clock" and watchdog reset, another drives a beeper.

An internal jumper enables partial compatibility with a 7854 mainframe in storage mode (displaying any single channel, 1+2 in ALT, or 3+4 in ALT only). There are no restrictions with the 7854 in analog mode.

Pictures

display - four signal traces plus trigger view
7A42 rear view
7A42 top view
Schematic cartoon: Bus
Schematic cartoon: Chirp

Internal

amplifier board (one attenuator cover removed)
amplifier board front - attenuators, amplifiers, channel switches
amplifier board rear - channel switches, two 15 ns delay lines
attenuator, cover removed
attenuator cover
attenuator, top
attenuator, one relay actuator removed
attenuator, all relay actuators removed
attenuator, all relay actuators removed
microprocessor board
memory backup battery on microprocessor board replaced with LiIon
internal switch mode PSU for digital logic supplies

Components

Some Parts Used in the 7A42

Part	Part Number(s)	Class	Description	Used in
148-0145-00	148-0145-00	Discrete component	miniature bi-stable relay actuator	7A42 • 119-1517-00
155-0038-01	155-0038-00 • 155-0038-01	Monolithic integrated circuit	5-bit current source D/A converter	7A42 • 7D13 • 7D14 • 7M13 • T4005
155-0078-00	155-0078-xx • 155-0273-00 • 155-0274-00	Monolithic integrated circuit	broadband amplifier	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
155-0236-00	155-0236-00	Hybrid integrated circuit	channel switch	2445 • 2465 • 7A42
ICM7218	156-1621-00 • 156-1622-00	Monolithic integrated circuit	8-digit, 7-segment LED driver	7A42
Intel 8085	156-1088-00	Monolithic integrated circuit	8-bit microprocessor	308 • 468 • 4025 • 7A42 • 7D02 • AFG5101 • AFG5102

@@ Line 1: / Line 1: @@
-{{Plugin Sidebar 2|
+{{Plugin Sidebar
-title=Tektronix 7A42|
+|manufacturer=Tektronix
-summary=350 MHz four-channel logic triggered amplifier|
+|series=7000-series scopes
-image=Tek-7a42-crop.jpg |
+|type=7A42
-caption=7A42 front view|
+|summary=350 MHz four-channel logic triggered amplifier
-introduced=1984 |
+|image=Tektronix 7A42 front.jpg
-discontinued=1990 |
+|caption=7A42 front view
-series=[[7000-series scopes]]|
+|introduced=1984
-manuals=
+|discontinued=1990
-* [http://w140.com/tek_7a42_service1_ocr.pdf 7A42 Service Manual Volume 1 (PDF)]
+|manuals=
-* [http://w140.com/tek_7a42_service2_ocr.pdf 7A42 Service Manual Volume 2 (PDF)]
+* [[Media:070-4285-00.pdf|7A42 Operator Manual]] (OCR)
+* 7A42 Service Manual
+** [[Media:070-4286-00.pdf|070-4286-00 Volume 1]] (OCR)
+** [[Media:070-4654-00.pdf|070-4654-00 Volume 2, Signature Analysis Tables]] (OCR)
+<small>
+'''ROM images'''
+* [[Media:160-1959-00.bin|160-1959-00.bin A8U145]]
+* [[Media:160-1960-00.bin|160-1960-00.bin A8U245]]
+* [[Media:160-1961-00.bin|160-1961-00.bin A8U340]]
+</small>
 }}
+The '''Tektronix 7A42''' is a four-channel 350 MHz plug-in for [[7000-series scopes]].  It is a double-wide plug-in, with signal outputs and mainframe readout only using the left slot.
-The '''Tektronix 7A42''' is a four-channel 350 MHz plug-in for [[7000-series scopes]].
+It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs.
+A fifth trace, "Trigger View", displays the trigger function output or external clock input.
-It was specifically designed for logic signals (TTL, ECL, CMOS) and supports triggering based on Boolean conditions of the four inputs.
+There are two sets of conditions, A and B, that can be individually selected or paired in an "A then B" mode called ''nested triggering'', where the occurrence of condition A arms the trigger and condition B causes the trigger to be generated.
+The trigger can be qualified by an external clock.  A trigger filter control, variable from 0-300 ns, allows events shorter than the selected length to be suppressed.  A TTL-level "reset" input will inhibit the trigger if active.
-A fifth trace, "Trigger View", displays the trigger function output or external clock input.
+Selected by an internal jumper, either the trigger signal, or the "A then B" interval, is available on a front-panel trigger output. This can e.g. be routed to a counter for time measurement or event counting.
 The input V/Div setting can only be seen in the mainframe's readout.
+There is a jumper to allow the readout to work in a [[7854]] mainframe.
+The trigger level is set digitally and shown on a 7-segment display.
-Tektronix recommended the [[P6131]] 10 MΩ probe, and the [[P6230]] variable-offset 450 Ω probe for ECL circuits.
+Tektronix recommended the [[P6131]], 300 MHz, 10 MΩ ×10 probe, and the [[P6230]], 1.5 GHz, 450/50 Ω ×10, variable-offset probe for ECL circuits.
+The [[067-1155-99]] calibration fixture is specific to the 7A42.
 {{BeginSpecs}}
-{{Spec | Bandwidth | 350 MHz}}
+{{Spec | Bandwidth | 350 MHz }}
 {{Spec | Deflection |
 * 0.1 / 0.2 / 0.5 V/Div (TTL mode)
 * 20 / 50 / 100 mV/Div (ECL mode)
-* each direct or through 10:1 probe}}
+* each direct or through 10:1 probe
-{{Spec | Input impedance | 1MΩ or 50 Ω}}
+* always DC coupled }}
+{{Spec | Input impedance | 1 MΩ // 15 pF or 50 Ω}}
 {{Spec | Max. input voltage |
-* at 1 MΩ: 25 V DC+peak AC below 36 MHz, down to 3 V AC at 300 MHz
+* at 1 MΩ: 25 V (DC+peak AC) below 36 MHz, down to 3 V<sub>AC</sub> at 300 MHz
-* at 50Ω: 5 V RMS during any 1 ms interval}}
+* at 50 Ω: 5 V<sub>RMS</sub> during any 1 ms interval}}
 {{Spec | Trigger level |
-* -1.27 to +1.28 V (TTL mode) in 10 mV steps
+* −1.27 to +1.28 V (TTL mode) in 10 mV steps
-* -254 mV to +256 mV (ECL mode) in 2 mV steps (or ×10)}}
+* −254 mV to +256 mV (ECL mode) in 2 mV steps (or ×10)}}
 {{Spec | Hysteresis | 40 mV (TTL), 8 mV (ECL) (or ×10)}}
 {{Spec | Features |
@@ Line 40: / Line 57: @@
 {{Spec | Weight | 2.8 kg / 6.2 lb}}
 {{EndSpecs}}
+==Links==
+{{Documents|Link=7A42}}
+==See also==
+* [[067-1155-99]]
+* [[A6701]]
+* [[821]]
 ==Internals==
-The 7A42's functions are controlled by an 8085A microprocessor.
+The 7A42's functions are controlled by an [[Intel 8085]]A microprocessor, with code in three 2764 EPROMs (a fourth ROM socket is unused).  The front-panel pushbuttons are handled by an Intel 8279 keyboard controller.
+Each of the four [[119-1517-00]] input attenuator modules contains five [[148-0145-00|148-0145-00 miniature bi-stable relay actuators]].  These have four long pins plugging in to the base board, driving two solenoids that move aa yoke which is held in the last active position by a permanent magnet.  The yoke moves a pair of contact springs that directly short corresponding pads on the thick-film ceramic substrate. The relay coils are wired in a 4×5 matrix.
+The 7A42 contains its own switch mode PSU, based on an SG3524 controller, that generates +5 V, −2 V and −5 V from the mainframe's ±50 V rails.
+There is a [[7A42/Repairs|NiCd backup battery]] that allows the unit to retain its last configuration.
-Each of the four input attenuator circuits contains five [[miniature relays]]. The bistable relay coils are wired in a 4x5 matrix.
+A 555 timer implements a 15 ms "real-time clock" and watchdog reset, another drives a beeper.
-The 7A42 contains its own switch mode PSU, based on an SG3524 controller, that generates +5 V, -2 V and -5 V from the mainframe's +/-50 V rails.
+An internal jumper enables partial compatibility with a [[7854]] mainframe in storage mode (displaying any single channel, 1+2 in ALT, or 3+4 in ALT only).  There are no restrictions with the 7854 in analog mode.
 ==Pictures==
 <gallery>
+Tektronix 7A42 front.jpg
 Tek 7a42.jpg
 Tek 7a42 1.jpg
 Tek 7a42 2.jpg
-Tek 7a42 3.jpg
-Tek 7a42 4.jpg
 Tek 7a42 fr1.jpg
 Tek 7a42 fr2.jpg
@@ Line 63: / Line 93: @@
 Tek 7a42 fr6.jpg | 7A42 rear view
 Tek 7a42 fr7.jpg | 7A42 top view
-Tek 7a42 fr8.jpg | memory backup battery
+Tek-7A42-Bus.jpg                       | Schematic cartoon: Bus
-Tek 7a42 fr9.jpg | internal switch mode PSU for digital logic supplies
+Tek-7A42-Chirp.jpg                     | Schematic cartoon: Chirp
-Tek 7a42 fr10.jpg | microprocessor board
+</gallery>
-Tek 7a42 fr11.jpg | amplifier board front - attenuators, amplifiers, channel switches
+'''Internal'''
-Tek 7a42 fr12.jpg | amplifier board rear - channel switches, two 15 ns delay lines
+<gallery>
-Tek 7a42 11.jpg
+A42 amplifier board.jpg  | amplifier board (one attenuator cover removed)
-Tek 7a42 12.jpg
+Tek 7a42 fr11.jpg         | amplifier board front - attenuators, amplifiers, channel switches
+Tek 7a42 fr12.jpg         | amplifier board rear - channel switches, two 15 ns delay lines
+A42 attenuator 1.jpg     | attenuator, cover removed
+A42 attenuator cover.jpg | attenuator cover
+A42 attenuator 2.jpg     | attenuator, top
+A42 attenuator 3.jpg     | attenuator, one relay actuator removed
+A42 attenuator 4.jpg     | attenuator, all relay actuators removed
+A42 attenuator 5.jpg     | attenuator, all relay actuators removed
+Tek 7a42 fr10.jpg         | microprocessor board
+Tek 7a42 fr8.jpg          | memory backup battery on microprocessor board replaced with LiIon
+Tek 7a42 fr9.jpg          | internal switch mode PSU for digital logic supplies
 Tek 7a42 13.jpg
 Tek 7a42 14.jpg
@@ Line 75: / Line 115: @@
 </gallery>
+==Components==
+{{Parts|7A42}}
 [[Category:7000 series vertical plugins]]