| Burroughs MBST Specifications |
|
| Written by Accutron on 2009-06-17 |
|
For photographs and historical information, please refer to the Beam Switching Tubes section of our electronics museum.
Key to Electrical Characteristics
F: Switching Speed
Et: Target Voltage
It: Target Current
Rt: Target Load Resistance
P/ta: Individual Target Dissipation
Es: Spade Voltage
Rs: Spade Resistance
Ecc: Grid Bias Voltage
Ej: Grid Switching Voltage
GZ: Grid Zero
Esg: Shield Grid Voltage
Ef: Heater Voltage
Ih: Heater Current
Ehk: Heater-Cathode Voltage
Eco: Firing Voltage
Prototype
Burroughs manufactured a number of unusual prototypes, including radial trochotrons and specialized BCD coding tubes. Little is known about these devices, and most types have no known examples.
| Type |
Envelope |
F |
Et |
It |
Rt |
P/ta |
Es |
Rs |
Ecc |
Ej |
GZ |
Ef |
Ih |
Ehk |
Eco |
Notes |
| DC-1 |
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
20-pin base. |
| DC-1R |
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
9-pin base; uncharacterized pin configuration. |
| TR-BC-11 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
BCD coding tube, sleeve-type anode. |
| TR-DC-11 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Counter, sleeve-type anode, internal spade resistors, 9-pin base. Same as DC-1R? |
| TR-SR-11 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Selector, sleeve-type anode. Same as DC-1? |
| SEL-10 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Radial internal configuration. |
| AF-12 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Experimental noise source. External magnet, B13B base. |
Standard Envelope
The earliest production types, represented by the 6700 and 6701, are the earliest types to be produced in quantity. These early models have a large cylindrical external magnet, plastic end caps, and no mu shield. Later on, Burroughs introduced shielded variants of these large models, making the final package even larger and more than twice as heavy. Some of the early models feature 'grid zero', where grid even, position zero can be triggered separately for faster resetting. In the standard 26-pin base, pin 11 is unused. In the grid zero pinout, grid zero is on pin 16, and the remainder of grid even is moved to pin 11. Additionally, Burroughs manufactured 10MHz types with internal spade lead resistors and an atypical 20-pin base.
| Type |
Envelope |
F |
Et |
It |
Rt |
P/ta |
Es |
Rs |
Ecc |
Ej |
GZ |
Ef |
Ih |
Ehk |
Eco |
Notes |
6700
HB-101
MO-10 |
|
2MHz |
100VDC
+/-10% |
5.5mA |
3.3k |
1W |
100VDC
+/-10% |
100k |
25VDC |
-50V |
No |
6.3VAC
+/-10% |
300mA |
+/-90VDC |
200VDC |
First production MBST, originally manufactured with Haydu label. |
| 6701 |
 |
1MHz |
20VDC
+/-15% |
0.6mA |
6.8k |
1W |
20VDC
+/-15% |
270k |
12VDC |
-20V |
Yes |
6.3VAC
+/-10% |
300mA |
+/-90VDC |
50VDC |
Low voltage, low speed variant of 6700 with grid zero. |
| BD-300 |
 |
2MHz |
100VDC
+/-15% |
6.5mA |
3.3k |
1W |
100VDC
+/-15% |
100k |
25VDC |
-50V |
Yes |
6.3VAC
+/-10% |
300mA |
+/-90VDC |
200VDC |
Variant of BD-301 with grid zero. |
BD-301
6703 |
|
2MHz |
100VDC
+/-15% |
6.5mA |
3.3k |
1W |
100VDC
+/-15% |
100k |
25VDC |
-50V |
No |
6.3VAC
+/-10% |
300mA |
+/-90VDC |
200VDC |
Shielded variant of 6700 with slightly higher target output and cathode current. |
| BD-308 |
|
1MHz |
20VDC
+/-15% |
0.6mA |
6.8k |
1W |
20VDC
+/-15% |
270k |
12VDC |
-20V |
Yes |
6.3VAC
+/-10% |
300mA |
+/-90VDC |
50VDC |
Shielded variant of 6701. |
MO-10R
6704 |
|
10MHz |
100VDC
+/-10% |
5.5mA |
3.3k |
1W |
100VDC
+/-10% |
100k
Internal |
25VDC |
-50V |
No |
6.3VAC
+/-10% |
300mA |
+/-90VDC |
200VDC |
High speed variant of 6700; internal 100K spade resistors, 20-pin base |
| BD-309 |
|
10MHz |
100VDC
+/-10% |
5.5mA |
3.3k |
1W |
100VDC
+/-10% |
100k
Internal |
25VDC |
-50V |
No |
6.3VAC
+/-10% |
300mA |
+/-90VDC |
200VDC |
Shielded variant of MO-10R. |
| BD-311 |
|
2MHz |
130VDC |
10mA |
3.3k |
|
130VDC |
82k |
30VDC |
-70V |
|
6.3VAC |
300mA |
|
|
High current variant of 6700. |
| BD-401 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Compact Envelope
First-generation beam switching tubes were large, heavy and expensive. Burroughs responded to the size issue by engineering a reduction in the diameter of the spade cage, which allowed for a corresponding reduction in the envelope, magnet and shield diameter. The miniature envelope style has a primary envelope diameter that is significantly smaller than the base of the envelope, flaring outward just above the pins to accomodate the size of the standard 26-pin base. Such tubes were also available in shielded and unshielded varieties, the shielded types being of the same diameter as a standard-size unshielded model.
| Type |
Envelope |
F |
Et |
It |
Rt |
P/ta |
Es |
Rs |
Ecc |
Ej |
GZ |
Ef |
Ih |
Ehk |
Eco |
Notes |
| BD-203 |
 |
1MHz |
55VDC
+/-10% |
3mA |
3.3k |
1W |
55VDC
+/-10% |
130k |
25VDC |
-50V |
Yes |
6.3VAC
+/-10% |
150mA |
+/-90VDC |
100VDC |
|
| BD-316 |
 |
1MHz |
55VDC
+/-10% |
3mA |
3.3k |
1W |
55VDC
+/-10% |
130k |
25VDC |
-50V |
Yes |
6.3VAC
+/-10% |
150mA |
+/-90VDC |
100VDC |
Shielded variant of BD-203. |
| BD-400 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Beam-X Switch
Reducing the size of the spade cage was a a limited solution. The so-called miniature tubes were still fairly large and fairly heavy, especially the more common shielded types. In 1960, Burroughs introduced a more radical solution. They returned the envelope to its original larger size, large enough to accomodate a new design with internal magnets.
These advanced tubes, sold under the Beam-X Switch trademark, have 10 small internal magnets and add a signal-improving shield grid. Beam-X Switch tubes are much smaller, lighter and faster than their external-magnet predecessors: the unshielded BX-1000 and BX-3000 are the smallest beam switching tubes ever produced, and are the size of a first generation tube minus the magnet and shield. Shielded Beam-X tubes are only slightly larger, and can be installed adjacently.
The Beam-X Switch pinout is identical to the standard 25-pin configuration, but adds the shield grid on pin 11. Unfortunately, this leaves no available pins for a grid zero reset function. Like earlier models, Beam-X Switch tubes were manufactured in both shielded and unshielded types.
| Type |
Envelope |
F |
Et |
It |
Rt |
P/ta |
Es |
Rs |
Ecc |
Ej |
Esg |
Ef |
Ih |
Ehk |
Eco |
Notes |
BX-1000
6710 |
 |
2MHz |
55VDC
+/-10% |
2.7mA
+/-30% |
3.3k |
1W |
55VDC
+/-10% |
150k |
40VDC |
-55V |
55VDC
+/-10% |
6.3VAC
+/-10% |
150ma
+/-10% |
+/-100VDC |
100V |
First Beam-X switch, multiple internal variations. |
| BX-1202 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
BX-1203
6713 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| BX-1204 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
BX-2000
6711 |
 |
2MHz |
55VDC
+/-10% |
2.7ma
+/-30% |
3.3k |
1W |
55VDC
+/-10% |
150k |
40VDC |
-55V |
55VDC
+/-10% |
6.3VAC
+/-10% |
150ma
+/-10% |
+/-100VDC |
100V |
Shielded variant of BX-1000. |
| BX-2001 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
High current variant of BX-2000. |
| BX-2003 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| BX-2004 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Used in 101P479 programmer. |
| BX-2005 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Used in 101P479 programmer. |
| BX-2012 |
|
2MHz |
55VDC
+/-10% |
2.7ma
+/-30% |
3.3k |
1W |
55VDC
+/-10% |
150k |
40VDC |
-55V |
55VDC
+/-10% |
6.3VAC
+/-10% |
150ma
+/-10% |
+/-100VDC |
100V |
BX-2000 specially tested for decoding BCD. |
| BX-2013 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
BX-3000
6712 |
|
2MHz |
80VDC |
5mA |
3.3k |
|
80VDC |
150k |
50VDC |
-55V |
|
6.3VAC |
150mA |
|
|
High current variant of BX-1000. |
| BX-3001 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| BX-4000 |
|
1MHz |
30VDC |
1mA |
10k |
|
30VDC |
270k |
26VDC |
-24V |
|
6.3VAC |
150mA |
|
|
Low voltage, low speed variant of BX-2000 |
BX-4001
6714 |
|
2MHz |
30VDC |
1mA |
10k |
|
30VDC |
270k |
26VDC |
-24V |
|
6.3VAC |
150mA |
|
|
Standard speed variant of BX-4000. |
| ©2000-2013
The Vintage Technology Association. All rights reserved. |  |
