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{{Oscilloscope Sidebar |
{{Oscilloscope Sidebar
title=Tektronix 434 |
|manufacturer=Tektronix
summary=24 MHz analog storage scope |
|series=400-series scopes
image=434 Tek 4.jpg |
|model=434
caption=Tek 434 |
|summary=24 MHz analog storage scope
introduced=1972 |
|image=434 Tek 4.jpg
discontinued=1984 |
|caption=Tek 434
manuals=
|introduced=1971
* [http://w140.com/tektronix_434_service.pdf Tektronix 434 Manual sn 500,000 and up (complete, PDF)]
|discontinued=1984
* [http://w140.com/434_below_B500000.pdf Tektronix 434 Manual sn below 500,000 (complete, PDF)]
|manuals=
* [http://w140.com/tek_434.pdf Tektronix 434 Manual (incomplete, PDF)]
* [[Media:070-1915-00.pdf|Tektronix 434 Instruction Manual SN 500,000+]] (complete, OCR)
* [[Media:070-1131-00.pdf|Tektronix 434 Instruction Manual, SN <500,000]] (complete, OCR)
* ''[[Media:070-1142-00.pdf|Tektronix 434 Operators Manual]] needed''
* [[Media:070-1142-01.pdf|Tektronix 434 Operators Manual (March 1984 Revision)]]
* [[Media:Tek 432 and 434 fcp april 1972.pdf|Tektronix 432 and 434 Factory Calibration Procedure, April 1972]]
}}
}}
The '''Tektronix 434''' is an analog [[CRT storage scope]] with two independent storage areas on the screen.  
The '''Tektronix 434''' is an analog [[CRT storage scope]] with two independent storage areas on the screen.  
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There is a chopped two channel system and the fastest sweep time is 20 ns/div.  
There is a chopped two channel system and the fastest sweep time is 20 ns/div.  
An option for a tube with higher sensitivity at high writing speeds was available (OPT. 01).
An option for a tube with higher sensitivity at high writing speeds was available (OPT. 01).
{{MissingSpecs}}
==Links==
* [[050-0674-00|Handle Replacement Modification Kit]]
{{Documents|Link=434}}
==Prices==
{| class="wikitable"
|-
! Year
! 1972
! 1973
! 1976
! 1980
|-
! Catalog Price
|align=right| $2,150
|align=right| $2,150
|align=right| $2,850
|align=right| $3,800
|-
! In 2023 Dollars
|align=right| $15,800
|align=right| $14,900
|align=right| $15,400
|align=right| $14,200
|}
==Internals==


The signal passes through rotary cam-operated input attenuators, then passes through an input amplifier
The signal passes through rotary cam-operated input attenuators, then passes through an input amplifier
that is on a separate small board.  The input amplifier contains a JFET source-follower buffer
that is on a separate small board.  The input amplifier contains a JFET source-follower buffer
that uses a [[2N5911|2N5911A]] (Tektronix part number 151-1032-00) biased with a drain current of 12.5 mA
that uses a [[2N5911|2N5911A]] (Tektronix part number 151-1032-00) biased with a drain current of 12.5 mA
and Vgs of -0.26 V.  The input amplifier has unity gain, high input impedance, and an output impedance of
and V<sub>gs</sub> of –0.26 V.  The input amplifier has unity gain, high input impedance, and an output impedance of
about 120 Ω.  The input amplifier drives a Tek-made differential amplifier chip, part number [[155-0050-01]].
about 120 Ω.  The input amplifier drives a Tek-made differential amplifier chip, part number [[155-0050-01]].


The original instrument design utilized an all-discrete switching power supply, making this an incredibly light portable scope. Unfortunately, this power supply was extremely difficult to troubleshoot when it went belly-up. At serial number B500000 and later, the design of the supply was simplified to use the same basic circuitry as found in the 7704A using a Tek-manufactured controller chip.
The original instrument design utilized an all-discrete switching power supply, making this an incredibly light portable scope.
Unfortunately, this power supply was extremely difficult to troubleshoot when it went belly-up.
At serial number B500000 and later, the design of the supply was simplified to use the same basic circuitry as found in the [[7704A]] using a [[155-0067-02|Tek-manufactured controller chip]].


In general, the 434 is a nice-looking, easy-to-use oscilloscope.  However, the 434 was probably one of the worst MECHANICAL scope designs to come out of Beaverton engineering.  This was the model that caused bench technicians to think that the factory should send all new mechanical engineers out into the field to work at a Service Center for a year to get an idea of good and bad mechanical designs.  First of all, the 434 design departed from the proven 4-40 steel PCB mounting screws.  Instead, it uses 3-48 brass screws in a design that requires a screw-holding driver to get the fasteners in place.  Brass screws are non-magnetic and getting them started in some of the more obscure places on the vertical preamp board is extremely difficult.  Since these scopes are of an age that one can make modifications without incurring the wrath of Tektronix technicians, it is suggested that these brass screws be replaced with steel 3-48 screws, preferably ones with captive washers like the original brass screws.  Most dedicated Tektronix fans and ex-technicians do not like changing any circuit design from the original, but some mechanical changes such as this are for everyone's benefit and don't affect operation of the oscilloscope in the least.
==Repair Issues==
 
See → [[434/Repairs|Repairs page]].
If the V/DIV knob skirt lamps go out, the vertical preamp board must be removed to replace them.  This is a process involving the removal of a lot of the aforementioned brass 3-48 screws, the removal of some connectors, the unsoldering of a lot of wires and the removal of knobs and shafts all over that area of the front panel.  Remember, it is always better to leave those red VAR V/DIV knobs on their shafts and instead remove knob and shaft as a unit by loosening it from the coupler on the potentiometer itself.  Since these oscilloscopes are considered obsolete, the suggestion is to replace ALL of the vertical knob skirt lamps with light emitting diodes, choosing either white or yellow LEDs.  These lamps already have small-value current limiting resistors on the circuit board that are in series, so replacing these resistors with the appropriate value to limit LED current is an easy process.  Be careful that you select an appropriate power rating for the resistors.  It is suggested that current be limited so that the panel lighting is sufficient for bright room lighting, but not so bright as to make it difficult to read the numbers on the knob skirts.
 
The 434 uses only two plug-in attenuators (both X10) in each channel, and most V/DIV switching involves gain switching of the preamp.  The 434 often cannot meet vertical gain specifications and some very low-value 5% tolerance resistors must be replaced to correct this.  These resistors are not located in an easy-to-access area of the board and once the defective resistors are identified, the board will need to be removed to allow replacement of the resistors without board damage.
 
Another common problem involves the mounting hardware for the back casting.  Nearly every 434 that was received in Tektronix Service Centers had to have these mounting screws tightened.  There is one located under the cover for the line cord and fuse. If that screw comes completely out, it is held captive inside that small space, and causes a lot of damage to the open mains connections on the fuse holder.  This is a job for a #2 Pozidriv screwdriver and a LOT of muscle torque.  Don't use a Phillips driver for this because it will "cam out" of the screw head with the torque that you must apply, causing screw head damage.  Regardless of how much torque you apply, you won't strip the casting rails or break the large 10-32 screws.  Tighten all of these casting-mounting screws by hand as tight as you possibly can.  Of course, do not use high-torque pneumatic or electric tools for this job.  Especially don't use the electric impact drivers that are so popular now in the construction industry.  The hardware DOES have its mechanical limitations.
 
==Specifications==
[[Category:Specifications needed]]
''please add''


==Pictures==
==Pictures==


<gallery>
<gallery>
Image:Tek 434.jpg
Tek 434.jpg
Image:Tek 434 a.jpg
Tek 434 a.jpg
Image:434 Tek 2.jpg
434 Tek 2.jpg
Image:434_Tek_3.jpg
434_Tek_3.jpg
Image:434 Tek 4.jpg
434 Tek 4.jpg
Image:434 Tek 5.jpg
434 Tek 5.jpg
Tek 434 trace.jpg
Tek 434 side connections.jpg|side connections
Tek 434 front up.jpg
</gallery>
</gallery>
==Components==
{{Parts|434}}


[[Category:400 series scopes]]
[[Category:400 series scopes]]
[[Category:Analog storage scopes]]

Latest revision as of 15:30, 27 October 2023

Tektronix 434
24 MHz analog storage scope
Tek 434

Produced from 1971 to 1984

Manuals
Manuals – Specifications – Links – Pictures

The Tektronix 434 is an analog CRT storage scope with two independent storage areas on the screen.

It has a bandwidth of 24 MHz and uses a tunnel diode in its trigger circuit. The storage is done in the CRT itself, by trapping charge on a special fine grid of isolated pads behind the phosphor where the electron beam is then blocked or released.

There is a chopped two channel system and the fastest sweep time is 20 ns/div. An option for a tube with higher sensitivity at high writing speeds was available (OPT. 01).

Key Specifications

  • please add

Links

Documents Referencing 434

Document Class Title Authors Year Links
Tekscope 1971 V3 N6 Nov 1971.pdf Article New Products 1971 211 • 434 • 4610
Tekscope 1972 V4 N5 Sep 1972.pdf Article Servicing the 432/434 Oscilloscopes Ken Matheson 1972 432 • 434

Prices

Year 1972 1973 1976 1980
Catalog Price $2,150 $2,150 $2,850 $3,800
In 2023 Dollars $15,800 $14,900 $15,400 $14,200

Internals

The signal passes through rotary cam-operated input attenuators, then passes through an input amplifier that is on a separate small board. The input amplifier contains a JFET source-follower buffer that uses a 2N5911A (Tektronix part number 151-1032-00) biased with a drain current of 12.5 mA and Vgs of –0.26 V. The input amplifier has unity gain, high input impedance, and an output impedance of about 120 Ω. The input amplifier drives a Tek-made differential amplifier chip, part number 155-0050-01.

The original instrument design utilized an all-discrete switching power supply, making this an incredibly light portable scope. Unfortunately, this power supply was extremely difficult to troubleshoot when it went belly-up. At serial number B500000 and later, the design of the supply was simplified to use the same basic circuitry as found in the 7704A using a Tek-manufactured controller chip.

Repair Issues

See → Repairs page.

Pictures

  • side connections

    side connections

Components

Some Parts Used in the 434

Part Part Number(s) Class Description Used in
151-0261-00 151-0261-00 Discrete component dual PNP transistor AM501 • AM502 • CG5001 • CG551AP • FG501 • FG502 • FG503 • OF150 • OF151 • OF152 • OF235 • OS261 • RM502A • R1140 • R5030 • R5031 • R7912 • 067-0679-00 • 067-0807-00 • 1101 • 1140A • 1141 • 1142 • 1350 • 145 • 1450 • 1480 • 1481 • 1482 • 1485 • 1501 • 1801 • 1900 • 1910 • 1980 • 213 • 26A1 • 26A2 • 2620 • 285 • 3A9 • 3A10 • 3S1 • 3S2 • 3S5 • 3S6 • 432 • 434 • 4501 • 454 • 4601 • 4602 • 4610 • 4612 • 4620 • 4632 • 4634 • 4701 • 475 • 492 • 492A • 492AP • 494 • 494P • 496 • 496P • 5A13N • 5A20N • 5A21N • 5A22N • 5A26 • 5L4N • 502A • 5030 • 5031 • 576 • 690SR • 7A22 • 7A29 • 7B51 • 7B71 • 7J20 • 7L5 • 7S11 • 7S12 • 7912AD
155-0028-00 155-0028-00 • 155-0028-01 • 155-0042-00 • 155-0042-01 • 155-0042-02 • 155-0042-03 Monolithic integrated circuit Miller integrator and delay pickoff 5030 • R5030 • 5031 • R5031 • 1401 • 1401A • 1480 • 1481 • 1482 • 1485 • 26G1 • 26G2 • 26G3 • 314 • 335 • 432 • 434 • 4701 • 5B10N • 5B12N • 5B31 • 5B40 • 5B42 • 5S14N • 7B52 • 7B53A • 7B53N • 7L12 • 7L13 • 7L14 • 7L18 • 7S14 • AN/USM-281C • RG501 • Telequipment D63 • Telequipment DM63
155-0050-01 155-0050-00 • 155-0050-01 Monolithic integrated circuit differential vertical preamplifier 432 • 434
155-0051-00 155-0051-00 Monolithic integrated circuit Z-axis and HV regulator 432 • 434
155-0067-02 155-0067-00 • 155-0067-02 • 155-0067-03 Monolithic integrated circuit SMPS controller 7704A • 7834 • 7844 • 7854 • 7904 • R7903 • 7904 • 7904A • 7934 • R7912 • 7912AD • 7912HB • 7934 • 7104 • R7103 • 308 • 434 • 485 • 690 • P7001
1N3717 152-0381-00 • 152-0125-00 Discrete component 4.7 mA, 25 pF tunnel diode 1L40 • 1S1 • 1S2 • 11B1 • 11B2 • 11B2A • 147A • 1470 • 148 • 21A • 22A • 3B4 • 3B5 • 408 • 432 • 434 • 453 • 453A • 454 • 466 • 491 • 5T3 • 544 • RM544 • 546 • RM546 • 547 • RM547 • 556 • RM556 • 7B70 • 7B71 • 7D11
2N5911 151-1032-00 Discrete component dual n-channel JFET 434 • 464
STD704 152-0125-00 Discrete component 4.7 mA tunnel diode 1L40 • 1S1 • 11B1 • 11B2 • 11B2A • 147 • R147 • 147A • R147A • 1470 • 148 • R148 • 148-M • 149 • R149 • 149A • R149A • 21A • 22A • 3B4 • 3B5 • 408 • 432 • 434 • 453 • 453A • 454 • 464 • 465 • 466 • 491 • 5T3 • 544 • RM544 • 546 • RM546 • 547 • RM547 • 556 • RM556 • 7B70 • 7B71 • 7D11
T4340 154-0666-10 • 154-0666-12 CRT storage CRT 434
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