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{{Oscilloscope Sidebar |
{{Oscilloscope Sidebar  
title=Tektronix 211 |
|manufacturer=Tektronix
summary=500 kHz miniature analog scope |
|series=200-series scopes
image=Tek 211 front.JPG |
|model= 211  
caption=Tektronix 211 |
|summary=500 kHz miniature analog scope  
introduced=1971 |
|image=Tek 211 front.JPG  
discontinued=1976 |
|caption=Tektronix 211  
manuals=
|introduced=1971
* [[Media:070-1163-00.pdf|Tektronix 211 Operator (PDF, OCR)]]
|discontinued=1976  
* [[Media:070-1163-00.pdf|Tektronix 211 Maintenance (PDF, OCR)]]
|designers=Dave Allen
* http://w140.com/Tek211_OpSVC.pdf
|manuals=
* [[Media:070-1163-00.pdf|Tektronix 211 Operator]] (OCR)
* [[Media:070-1160-00.pdf|Tektronix 211 Maintenance]] (OCR)
}}
}}
The '''Tektronix 211''' is a 500 kHz single-channel miniaturized analog battery-powered oscilloscope. The 1MΩ input probe is directly wired to the instrument. External trigger and horizontal inputs are provided via banana jack.  
The '''Tektronix 211''' is a 500 kHz single-channel miniaturized analog battery-powered oscilloscope.  
The 1 MΩ input probe is directly wired to the instrument. External trigger and horizontal inputs are provided via banana jack.
The 211 "Miniscope" was developed by a group led by [[Dave Allen]].


{{BeginSpecs}}
{{BeginSpecs}}
{{Spec | Bandwidth |   Max - DC to 500 kHz for 10 mV/div to 50 V/div, Min -  DC to 100 kHz at 1 mV/div }}
{{Spec | Bandwidth | DC to 500 kHz (100 kHz at 1 mV/div) }}
{{Spec | Input Impedance | 1 MΩ // 130 pF }}
{{Spec | Input Impedance | 1 MΩ // 130 pF }}
{{Spec | Input Voltage | max. 600V (DC + Peak ACor 600 V<sub>p-p</sub> AC  }}
{{Spec | Input Voltage | max. 600 V DC + peak AC, or 600 V<sub>p-p</sub> AC  }}
{{Spec | Sweep Range | 200 ms to 5 μs  per division }}
{{Spec | Sweep Range | 200 ms to 5 μs  per division }}
{{Spec | CRT | [[154-0642-00]] (<B080000) or [[154-0699-00]], 6(V) × 10(H) }}
{{Spec | CRT | [[154-0642-00]] (<B080000) or [[154-0699-00]], 6(V) × 10(H) }}
{{Spec | Operating Time on Battery | 3-5 Hours with maximum intensity  }}
{{Spec | Battery Runtime | 3-5 Hours with maximum intensity  }}
{{Spec | Internal Battery | 10 Rechargable NiCd cells }}
{{Spec | Battery | 10 rechargeable NiCd cells }}
{{Spec | Line Voltage | 110-126V <sub>AC</sub> ±10%, 58 Hz to 62 Hz }}
{{Spec | Line Voltage | 110-126V <sub>AC</sub> ±10%, 58−62 Hz }}
{{Spec | Power Consumption | < 2 W @ 126 V<sub>AC</sub> / 60 Hz}}
{{Spec | Power Consumption | < 2 W @ 126 V<sub>AC</sub>, 60 Hz}}
{{Spec | Dimensions  | (H/W/D) 3" × 5.2" × 8.9" (7.6 cm x 13.2 cm x 22.6 cm)  }}
{{Spec | Dimensions  | (H/W/D) 3" × 5.2" × 8.9" (7.6 cm x 13.2 cm x 22.6 cm)  }}
{{Spec | Weight | 3 lbs/1.38kg }}
{{Spec | Weight | 3 lbs/1.38 kg }}
{{EndSpecs}}
{{EndSpecs}}


==Internals==
==Internals==
==Vertical==
===Vertical===
The probe input first goes through compensated attenuators and then into one gate of Q18, a dual JFET.  
The probe input first goes through compensated attenuators and then into one gate of Q18,  
The drains of the dual JFET drive the inputs of dual output amplifier IC  U25, part number [[155-0057-00]].  
a dual JFET. The drains of the dual JFET drive the inputs of dual output amplifier IC  U25,  
U25 drives one section of dual output amplifier U105 [[155-0047-00]]  which drives CRT V-plates via  output transistors Q110/Q107
part number [[155-0057-00]]. U25 drives one section of dual output amplifier U105 [[155-0047-00]]  which drives CRT V-plates via  output transistors Q110/Q107.
 
 
==Horizontal==
Triggering is done using  U65 [[155-0048-01]], which contains external horizontal amplifier, trigger and sweep generator.
Output of U65 drives the second section of dual output amplifier IC  U25 [[155-0057-00]] who's output is fed to the H-plates via output transistors  Q119/Q122.
U65 is  mounted on the input board. Unblanking signal from U65 is driven to CRT via Q134


===Horizontal===
Triggering is done using  U65 [[155-0048-01]], which contains a horizontal amplifier (for external), trigger, and sweep generator.
The output of U65 drives the second section of dual output amplifier IC  U25 [[155-0057-00]] whose output is fed to the H-plates via output transistors  Q119/Q122.
U65 is mounted on the input board. The unblanking signal from U65 is driven to CRT via Q134.


==Power Supply==
===Power Supply===
Tek 211 can be operated from line power or internal Ni-Cd battery. Line power is also used for charging the batteries.
Tek 211 can be operated from line power or the internal Ni-Cd battery. Line power is also used for charging the batteries. Internally the unit uses a DC-DC converter to generate the required voltages from the battery or line, using Q242, Q249, and T250. DC-DC converter generates  
Internally the unit uses a DC-DC converter to generate the required voltages from battery or line, using Q242, 2459 and T250.
the +5.6 V, -5.6 V, and +65 V used in the unit. -1 kV for CRT is generated using a voltage multiplier.
DC-DC converter generates the +5.6, -5.6 and +65 used in the unit.
-1000V for CRT is generated using voltage multiplier.  


Instead of transformer, capacitive divider is used to step-down down the line voltage.
Instead of the transformer, a capacitive divider is used to step-down down the line voltage. C210 is the capacitor for providing charging voltage and C212 gets parallel to C210 for line operation. The value of these capacitors needs to be adjusted based on operating line frequency and voltage. Manual suggests recommended values of these capacitors for common line frequency and voltages. Input AC must be sinusoidal to offer the correct reactance to step-down the line voltage.
C210 is the capacitor for providing charging voltage and C212 gets parallel to C210 for for line operation.
Value of these capacitors needs to be adjusted based on operating line frequency and voltage.  
Manual suggests recommended values of these capacitors for common line voltages.  
Input AC must be sinusoidal to offer the correct reactance to step-down the line voltage.
 
Like other instruments of the era  there are no filter capacitors in the power supply, rather the battery is used as the filter capacitor.
Hence disconnecting battery can affect the unit's operation.  


Like other instruments of the era, there are no filter capacitors in the power supply, rather the battery is used as the filter capacitor. Hence disconnecting the battery can affect the unit's operation.


==Background==
==Background==


Regarding his experience as a Tektronix manufacturing engineer for the CRTs for the Miniscope
Regarding his experience as a Tektronix manufacturing engineer for the CRTs for the Miniscope
series (211, [[212]], [[213]], and [[214]]), Dale Dorando recalls:
series (211, [[212]], [[213]], and [[214]]), [[Dale Dorando]] recalls:
<blockquote>
<blockquote>
I worked under Bill Johnson, one of
I worked under [[Bill Johnson]], one of the manufacturing managers, especially the  
the manufacturing managers, especially the flood guns used in the storage CRT's.
flood guns used in the storage CRT's.
I was the weld lab manager too.  We designed, tested, selected electrodes, and weld
I was the weld lab manager too.  We designed, tested, selected electrodes, and weld
settings for the elements inside the CRT.  
settings for the elements inside the CRT.  
<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>
 
The CRT's  for the 211, 212, 213, and the storage version, 214, were manufactured
The CRTs 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.  
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
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,
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
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
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.
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 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
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
these four operators, the yield and volume for the Miniscope CRT became much higher
than the conventional CRT's.
than the conventional CRTs.
<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
several tries to get that right.  It was being done in conjunction with our partner,
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.
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
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
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
temperature.  This was important for a battery operated device.  The spacing
Line 95: Line 88:
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>
 
As with most of the Tektronix CRT's, it used deflection blanking where the beam is
As with most of the Tektronix CRTs, it used deflection blanking where the beam is
aimed off the screen during the horizontal retrace.  This was faster and easier to
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
control with the associated electronics than changing the negative high voltage with
respect to the grid.
respect to the grid.
<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>
 
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
bulb was frit bonded at high temperatures to the glass neck.  The faceplate was also
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
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
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
settle in a liquid onto the faceplate.  The liquid was poured out and then aluminum
Line 113: Line 106:
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>
 
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
neck, that was previously bonded to the ceramic bulb, and using a lathe with a
neck, that was previously bonded to the ceramic bulb, and using a lathe with a
Line 121: Line 114:
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>
 
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
oscilloscope.  This would correct for any small gun rotational alignment.
oscilloscope.  This would correct for any small gun rotational alignment.
</blockquote>
</blockquote>
==See Also==
* [https://www.youtube.com/watch?v=BJTZIawR1Iw LazyElectrons Video: Tektronix 211 - Internals, battery replacement]
==Prices==
{| class="wikitable"
|-
! Year
! 1973
|-
! Catalog Price
| $545
|-
! In 2023 Dollars
| $3,800
|}


==Pictures==
==Pictures==
Line 133: Line 143:
Tek 211 right2.JPG | 211 RHS
Tek 211 right2.JPG | 211 RHS
Tek_211-wHood.jpeg | 211 with Viewing Hood Part [[016-0199-00]]
Tek_211-wHood.jpeg | 211 with Viewing Hood Part [[016-0199-00]]
200 series compared.jpg | Tek [[214]] (top), [[213]] (center) and [[211]] (bottom) stacked
Tek_211_Vs_555.jpeg | Size comparison, 211 vs. [[555]]
Tek_211-BatLevel.jpeg | 211 Battery charge meter
Tek_211-BatLevel.jpeg | 211 Battery charge meter
200 series compared.jpg | Tek [[214]] (top), [[213]] (center) and [[211]] (bottom) stacked
Tek_211-Internal-Top.jpeg | 211 Internal top
211 int 01.jpg | 211 Internal bottom
Tek_211-Top-WoAmp.jpeg | 211 Top w/o amplifier board
Tek_211-Top-WoAmp.jpeg | 211 Top w/o amplifier board
Tek_211-Internal-Bottom.jpeg | 211 Internal bottom
Tek_211-Internal-Bottom.jpeg | 211 Internal bottom
Tek_211-Internal-Top.jpeg | 211 Internal top
211 int 01.jpg | 211 Internal bottom w/o PS board
Tek_211-Int-Side.jpeg | 211 Internal LHS
Tek_211-Int-Side.jpeg | 211 Internal LHS
211 int 05.jpg | Input Board (rear)
Tek_211-Inputboard.jpeg | Tek 211 Input board (rear)
211 int 08.jpg | Input board front (w/o front panel)
211 int 02.jpg | Amplifier board  
211 int 02.jpg | Amplifier board  
211 int 03.jpg | Amplifier board  
211 int 03.jpg | Amplifier board  
Tek_211-OPTransistors.jpeg | Output transistors
211 int 06.jpg | Amplifier board (trace side)
211 int 04.jpg | Power supply board
211 int 04.jpg | Power supply board
Tek_211-PSBoardwBat.jpeg | Power supply board w battery
Tek_211-PSBoardwBat.jpeg | Power supply board and battery
Tek_211-PS-Capacitor.jpeg | Dropping Caps in power supply
211 int 05.jpg | Input Board (rear)
Tek_211-Inputboard.jpeg | Tek_211-Inputboard.jpeg (rear)
211 int 06.jpg | Amplifier board (trace side)
211 int 07.jpg | Power supply board (trace side)
211 int 07.jpg | Power supply board (trace side)
211 int 08.jpg | Input Board Front (w/o Front panel)
Tek_211-OPTransistors.jpeg | Output transistors
Tek_211-PS-Capacitor.jpeg | Dropping caps in power supply
Tek 211 battery pack.jpg|Tek 211 internal battery pack
Tek 211 battery pack.jpg|Tek 211 internal battery pack
Tek_211_Vs_555.jpeg | 211 to 555 - Size comparison
</gallery>
</gallery>
==Components==
{{Parts|211}}


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

Latest revision as of 14:29, 27 October 2023

Tektronix 211
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. The 1 MΩ input probe is directly wired to the instrument. External trigger and horizontal inputs are provided via banana jack. The 211 "Miniscope" was developed by a group led by Dave Allen.

Key Specifications

Bandwidth DC to 500 kHz (100 kHz at 1 mV/div)
Input Impedance 1 MΩ // 130 pF
Input Voltage max. 600 V DC + peak AC, or 600 Vp-p AC
Sweep Range 200 ms to 5 μs per division
CRT 154-0642-00 (<B080000) or 154-0699-00, 6(V) × 10(H)
Battery Runtime 3-5 Hours with maximum intensity
Battery 10 rechargeable NiCd cells
Line Voltage 110-126V AC ±10%, 58−62 Hz
Power Consumption < 2 W @ 126 VAC, 60 Hz
Dimensions (H/W/D) 3" × 5.2" × 8.9" (7.6 cm x 13.2 cm x 22.6 cm)
Weight 3 lbs/1.38 kg

Internals

Vertical

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 dual output amplifier IC U25, part number 155-0057-00. U25 drives one section of dual output amplifier U105 155-0047-00 which drives CRT V-plates via output transistors Q110/Q107.

Horizontal

Triggering is done using U65 155-0048-01, which contains a horizontal amplifier (for external), trigger, and sweep generator. The output of U65 drives the second section of dual output amplifier IC U25 155-0057-00 whose output is fed to the H-plates via output transistors Q119/Q122. U65 is mounted on the input board. The unblanking signal from U65 is driven to CRT via Q134.

Power Supply

Tek 211 can be operated from line power or the internal Ni-Cd battery. Line power is also used for charging the batteries. Internally the unit uses a DC-DC converter to generate the required voltages from the battery or line, using Q242, Q249, and T250. DC-DC converter generates the +5.6 V, -5.6 V, and +65 V used in the unit. -1 kV for CRT is generated using a voltage multiplier.

Instead of the transformer, a capacitive divider is used to step-down down the line voltage. C210 is the capacitor for providing charging voltage and C212 gets parallel to C210 for line operation. The value of these capacitors needs to be adjusted based on operating line frequency and voltage. Manual suggests recommended values of these capacitors for common line frequency and voltages. Input AC must be sinusoidal to offer the correct reactance to step-down the line voltage.

Like other instruments of the era, there are no filter capacitors in the power supply, rather the battery is used as the filter capacitor. Hence disconnecting the battery can affect the unit's operation.

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 CRTs 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 four operators, the yield and volume for the Miniscope CRT became much higher than the conventional CRTs.

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 CRTs, 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.

See Also

Prices

Year 1973
Catalog Price $545
In 2023 Dollars $3,800

Pictures

Components

Some Parts Used in the 211

Part Part Number(s) Class Description Used in
154-0642-00 154-0642-00 CRT CRT for miniature scopes 211
154-0699-00 154-0699-00 154-0699-50 CRT directly-heated CRT for miniature scopes 211 212 SC501
155-0047-00 155-0047-00 Monolithic integrated circuit dual variable-gain amplifier 211 212 214
155-0048-01 155-0048-00 155-0048-01 155-0055-00 155-0055-01 Monolithic integrated circuit trigger sweep 211 212 213 214 432 433 5B12N 5B13N 5L4N 603 604 605 606 607 624 SC501 R7912
155-0057-00 155-0057-00 Monolithic integrated circuit amplifier 211