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Burroughs 6700 / MO-10 / HB-101
Written by Accutron on 2007-03-19

Description

Devices included in this entry:

Haydu 6700 unshielded MBST (pictured in thumbnail)
Burroughs MO-10 unshielded MBST
Burroughs 6700 unshielded MBST
Burroughs JAN-CBSC-6700 unshielded MBST

The 6700 is the first mass-produced beam switching tube, developed by Burroughs as a 2 MHz counter for use in computers. All subsequent beam switching tubes developed by Burroughs are direct descendants of the 6700.

Haydu Bros. began mass-producing Burroughs tube designs shortly after they were acquired by Burroughs in 1954. The earliest Nixie and beam switching tubes have dual branding, with Haydu in the foreground and 'Subsidiary of Burroughs' condemned to fine print.

The inexplicable inversion of due credit still causes confusion to this day, as many sources either partially or completely credit Haydu with the development of these tubes, when in fact Haydu was not involved in their development at all. The earliest known advertisement for the Haydu 6700 clearly states that the 6700 was perfected by the Burroughs Research Center, and mass-produced by the Haydu tube division. The extensive patent history of Nixie and beam switching tubes also supports this assertion, with all related inventors listed as assignors of Burroughs Corporation.

By 1957, the misleading Haydu branding was abandoned. As a result, the 6700 is the only Burroughs beam switching tube known to be branded as a Haydu product.

Detail

The Haydu 6700 has an orange plastic label wrapped around the magnet, instead of bare iron like later Burroughs-branded variations.


Unlike later 6700s, the Haydu 6700 does not have a domed top cap; instead, the top and bottom caps are identical, both resembling the bottom caps found on all variations.


Haydu 6700, shown with box.


Extremely rare example of a Burroughs MO-10. The 6700 was only briefly sold under the MO-10 part number, and this is currently the only known surviving example of this variation.


Burroughs MO-10 with four-digit serial number, manufactured in 1957. The chronological placement of the MO-10 is not yet confirmed. Its branding and cap configuration would suggest that the MO-10 falls between the orange-label Haydu 6700 and the red-label Burroughs 6700 pictured below, but the four-digit serial number may suggest otherwise.


The Burroughs MO-10 was distributed in a standard Haydu box, with a military white box-style label affixed to the lid. This MO-10 was packed in 1957 and shipped to Westinghouse under military contract.


The earliest Burroughs-branded 6700s also have a label instead of a stamp, but red with the Burroughs logo in black. This variation has a black domed top cap, and a clear Haydu-style bottom cap. A slightly later variation retains the red printed label, but has a different print arrangement and black bottom cap like later bare iron variations.


Early beam switching tubes were printed with a serial number.


Early 6700 box with matching red, black and white.


JAN variant 6700.