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[[Image:Tek1401a-front.jpg|thumb|600px|right|Tektronix 1401A Spectrum Analyzer Module]] | [[Image:Tek1401a-front.jpg|thumb|600px|right|Tektronix 1401A Spectrum Analyzer Module]] | ||
The Tektronix 1401A is a swept front-end spectrum analyzer covering the frequency range | |||
It | of 1 MHz to 500 MHz. It is designed to use an external oscilloscope, typically a [[323]], | ||
typically a [[323]] or [[ | [[324]] or [[326]]. It has internal rechargable NiCd batteries and can also operate | ||
as | from AC power (using an unusual power cord) or external DC from 6V to 16V. | ||
The 1401A | |||
There appear to be two variants of the 1401A, both the manual and | |||
catalog specify the resolution bandwidth selector as 1000, 100 and 3 KHz, | |||
but the later versions are 100, 100, and 10 KHz. | |||
The 1401A is designed to be used with an oscilloscope with 10 horizontal | |||
divisions and 6 vertical divisions. Note that most full sized Tektronix | |||
oscilloscopes have 8 vertical divisions so use care when doing the | |||
initial setup and reading the scale in dBm. | |||
See TekScope January 1972 pages 14-15 for some servicing notes that | See TekScope January 1972 pages 14-15 for some servicing notes that | ||
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It is a 152-0402-00, a 2mA, 25pF tunnel diode in a DO-17 package. | It is a 152-0402-00, a 2mA, 25pF tunnel diode in a DO-17 package. | ||
It's only necessary if you use the external trigger input. | It's only necessary if you use the external trigger input. | ||
There is one Tektronix custom IC, 155-0042-02, listed as a Miller Integrator. | |||
It is used to generate the sweep ramp voltage. The package is a | |||
10 pin metal can. | |||
The input attenuator is a fairly custom part due to the IF gain pot | The input attenuator is a fairly custom part due to the IF gain pot | ||
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attenuator is easy after removing it from the 1401A. Note that the | attenuator is easy after removing it from the 1401A. Note that the | ||
IF gain pot is removed via two allen setscrews. To bench test the | IF gain pot is removed via two allen setscrews. To bench test the | ||
attenuator with DC, use a 50 ohm terminator | attenuator with DC, use a 50 ohm terminator on SMA input and connect | ||
the output SMA to an ohm meter. Each of the seven steps should read | |||
around 50 ohms. The contacts on the ceramic attenuator elements | |||
can wear, they can be repaired with silver solder. Before reassembly, | |||
remove the two SMA housings to avoid damaging the contacts and remove | |||
the setscrews that hold spring tension on the two ball bearings | |||
that align the shaft steps. Reinstall these parts after the housing | |||
has been screwed together. | |||
<gallery> | |||
Image:Tek1401a-front.jpg|Front panel | |||
Image:tek1401a-top.jpg|Top PCB: IF board | |||
Image:tek1401a-bottom.jpg|Bottom PCBs:gate/cal, power supply | |||
Image:tek1401a-batterypcb.jpg|PCB on the battery pack | |||
</gallery> | |||
* [[List of manuals that are needed|Manual needed]] | * [[List of manuals that are needed|Manual needed]] |
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