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| discontinued=1984 | | | discontinued=1984 | |
| manuals= | | manuals= |
| * [http://w140.com/tektronix_434_service.pdf Tektronix 434 Manual sn 500,000 and up (complete, PDF)] | | * [[Media:070-1915-00.pdf|Tektronix 434 Instruction Manual SN 500,000+]] (complete, OCR) |
| * [http://w140.com/434_below_B500000.pdf Tektronix 434 Manual sn below 500,000 (complete, PDF)] | | * [[Media:070-1131-00.pdf|Tektronix 434 Instruction Manual, SN <500,000]] (complete, OCR) |
| | * [[Media:Tek 432 and 434 fcp april 1972.pdf|Tektronix 432 and 434 Factory Calibration Procedure, April 1972]] (PDF) |
| | <!-- old non-wiki upload locations |
| | * [http://w140.com/tektronix_434_service.pdf Tektronix 434 Manual sn 500,000 and up] (complete) |
| | * [http://w140.com/434_below_B500000.pdf Tektronix 434 Manual sn below 500,000] (complete)] |
| * [http://w140.com/tek_434.pdf Tektronix 434 Manual (incomplete, PDF)] | | * [http://w140.com/tek_434.pdf Tektronix 434 Manual (incomplete, PDF)] |
| | | --> |
| * [[Media:070-1915-00.pdf|Tektronix 434 Manual sn 500,000and up (complete, PDF, OCR, bad-OCR)]]
| |
| * [[Media:070-1131-00.pdf|Tektronix Maunal sn below 500,000 (complete, PDF, OCR)]]
| |
| * [[Media:Tek 432 and 434 fcp april 1972.pdf|Tektronix 432 and 434 Factory Calibration Procedure, April 1972 (PDF, needs OCR)]]
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| }} | | }} |
| 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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| ==Repair Issues== | | ==Repair Issues== |
| In general, the 434 is a nice-looking, easy-to-use oscilloscope.
| | See → [[434/Repairs|Repairs page]]. |
| 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.
| |
| In fact, if the circuit boards are removed, the original 3-48 threaded holes
| |
| in the castings can be drilled out and retapped for 4-40 screws.
| |
| | |
| 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 ×10) 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 extruded aluminum 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.
| |
|
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| ==Links== | | ==Links== |
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| </gallery> | | </gallery> |
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| | | {{CRTs|434}} |
| {{Custom ICs|434}} | | {{Custom ICs|434}} |
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