211: Difference between revisions

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caption=Tektronix 211 |
caption=Tektronix 211 |
introduced=1971 |
introduced=1971 |
discontinued=(?) |
discontinued=1976 |
manuals=
manuals=
* [http://w140.com/Tek211_OpSVC.pdf Tektronix 211 Manual (PDF)]
* [[Media:070-1163-00.pdf|Tektronix 211 Operator (PDF, OCR)]]
* [[Media:070-1163-00.pdf|Tektronix 211 Maintenance (PDF, OCR)]]
}}
}}
The '''Tektronix 211''' is a 500 kHz single-channel miniaturized analog battery-powered oscilloscope.
The '''Tektronix 211''' is a 500 kHz single-channel miniaturized analog battery-powered oscilloscope.
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settings for the elements inside the CRT.  
settings for the elements inside the CRT.  
<br>
<br>
<br>
The CRT division had a great concept where the new engineers work at each station
The CRT division had a great concept where the new engineers work at each station
for a week or two learning all the processes and actually making parts.  The side
for a week or two learning all the processes and actually making parts.  The side
advantage is you meet the production people and when you need something you know who
advantage is you meet the production people and when you need something you know who
to ask.
to ask.
<br>
<br>
<br>
The CRT's  for the 211, 212, 213, and the storage version, 214, were manufactured
The CRT's  for the 211, 212, 213, and the storage version, 214, were manufactured
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these 4 operators. The yield and volume for the Miniscope CRT  became much higher
these 4 operators. The yield and volume for the Miniscope CRT  became much higher
than the conventional CRT's.
than the conventional CRT's.
<br>
<br>
<br>
The cathode for the Miniscope CRT was a critical part of the design.  It took
The cathode for the Miniscope CRT was a critical part of the design.  It took
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The cathode was a small disk with the triple carbonate coating blown on to the
The cathode was a small disk with the triple carbonate coating blown on to the
surface at a precise thickness.
surface at a precise thickness.
<br>
<br>
<br>
As with most of the Tektronix CRT's, it used deflection blanking where the beam is
As with most of the Tektronix CRT's, it used deflection blanking where the beam is
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control with the associated electronics than changing the negative high voltage with
control with the associated electronics than changing the negative high voltage with
respect to the grid.
respect to the grid.
<br>
<br>
<br>
Glass rods hold the elements in place inside the CRT.  Having so many elements
Glass rods hold the elements in place inside the CRT.  Having so many elements
embedded in such a small glass rod made them fragile.  The rodding process was
embedded in such a small glass rod made them fragile.  The rodding process was
carefully controlled for temperature and time.
carefully controlled for temperature and time.
<br>
<br>
<br>
The bulb of the CRT was ceramic with an internal gold plating as the anode.  The
The bulb of the CRT was ceramic with an internal gold plating as the anode.  The
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resist burning the phosphor and reflected the light from the back to the front for a
resist burning the phosphor and reflected the light from the back to the front for a
brighter sweep.
brighter sweep.
<br>
<br>
<br>
The electron gun was welded to the stem with the pins.  That was inserted into the
The electron gun was welded to the stem with the pins.  That was inserted into the
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flash, the better is absorbed the impurities, but too much flashing could short out
flash, the better is absorbed the impurities, but too much flashing could short out
metal parts.
metal parts.
<br>
<br>
<br>
A coil was wound around the CRT to allow for a trace rotation adjustment in the
A coil was wound around the CRT to allow for a trace rotation adjustment in the
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<gallery>
<gallery>
File:Tek 211 front.JPG
Tek 211 front.JPG | 211 front view
File:Tek 211 right2.JPG
Tek 211 right2.JPG | 211 right side view
200 series compared.jpg | 200 series comparison
211 int 01.jpg | 211 internal
211 int 02.jpg
211 int 03.jpg
211 int 04.jpg
211 int 05.jpg
211 int 06.jpg
211 int 07.jpg
211 int 08.jpg
</gallery>
</gallery>


[[Category:200 series scopes]]
[[Category:200 series scopes]]
[[Category:Introduced in 1972]]
[[Category:Introduced in 1972]]

Revision as of 04:58, 8 March 2018

{{{manufacturer}}} 
500 kHz miniature analog scope
Tektronix 211

Produced from 1971 to 1976

Manuals
(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix 211 is a 500 kHz single-channel miniaturized analog battery-powered oscilloscope.

Key Specifications

  • please add

Internals

The probe input first goes through compensated attenuators and then into one gate of Q18, a dual JFET. The drains of the dual JFET drive the inputs of an amplifier IC, U25, part number 155-0057-00.

Triggering is done using a 155-0048-01.

The 211 uses a 155-0047-00 for X and Y amplification until the final stages, which use NPN transistors to drive the CRT deflection plates.

The CRT is a 154-0642-00 (<B080000) or 154-0699-00.

Background

Regarding his experience as a Tektronix manufacturing engineer for the CRTs for the Miniscope series (211, 212, 213, and 214), Dale Dorando recalls:

I worked under Bill Johnson, one of the manufacturing managers, especially the flood guns used in the storage CRT's. I was the weld lab manager too. We designed, tested, selected electrodes, and weld settings for the elements inside the CRT.
The CRT division had a great concept where the new engineers work at each station for a week or two learning all the processes and actually making parts. The side advantage is you meet the production people and when you need something you know who to ask.
The CRT's for the 211, 212, 213, and the storage version, 214, were manufactured using a pilot program where the same assembler worked on all phases of the tube. The other CRT's were being built by a person that only did one portion of the assembly. As an example, the deflection plates were assembled and carefully aligned, the next operator may not realize that and if accidentally bent, tried to bend them back. Naturally they wouldn't be properly aligned. By having the same people perform every process, they could see what was important and what could be improved. The primary goal was to find ways to improve the processes. By performing all the steps it was easier to find these improvements. The result was that with just these 4 operators. The yield and volume for the Miniscope CRT became much higher than the conventional CRT's.
The cathode for the Miniscope CRT was a critical part of the design. It took several tries to get that right. It was being done in conjunction with our partner, Sony. Sony was to use the same 1/4 watt cathode in the Trinitron TV. The cathode was a direct heated type - the filament and cathode were on the same flat wire. This reduced the power necessary to heat the cathode to the required temperature. This was important for a battery operated device. The spacing between the cathode and the grid with extremely important for the intensity and spot size. If the filament deformed while being heated, the cathode could move. The filament had springs that kept it taught across a ceramic ring inside the grid cup. The cathode was a small disk with the triple carbonate coating blown on to the surface at a precise thickness.
As with most of the Tektronix CRT's, it used deflection blanking where the beam is aimed off the screen during the horizontal retrace. This was faster and easier to control with the associated electronics than changing the negative high voltage with respect to the grid.
Glass rods hold the elements in place inside the CRT. Having so many elements embedded in such a small glass rod made them fragile. The rodding process was carefully controlled for temperature and time.
The bulb of the CRT was ceramic with an internal gold plating as the anode. The bulb was frit bonded at high temperatures to the glass neck. The faceplate was also frit bonded to the ceramic bulb. The faceplate was first silkscreened with the graticule. After the faceplate was bonded to the bulb, the phosphor was allowed to settle in a liquid onto the faceplate. The liquid was poured out and then aluminum pellets were evaporated on to the phosphor in a mild vacuum. The aluminum helped resist burning the phosphor and reflected the light from the back to the front for a brighter sweep.
The electron gun was welded to the stem with the pins. That was inserted into the neck, that was previously bonded to the ceramic bulb, and using a lathe with a torch, melted the stem to the neck. The CRT was evacuated and the metals inductively heated to remove the gasses in the metal, then sealed. The getter was inductively flashed to a size dictated by a template for that CRT. The larger the flash, the better is absorbed the impurities, but too much flashing could short out metal parts.
A coil was wound around the CRT to allow for a trace rotation adjustment in the oscilloscope. This would correct for any small gun rotational alignment.

Pictures