Artifact Details


Whirlwind vacuum tube module rack

Catalog Number



Physical object



Identifying Numbers

Other number E15-7 Engraved white on black on a plastic label attached upside down to the right end of the upper channel.
Other number E15-7 Written in ball point pen on a paper sticker attached to the back of the left end of the upper channel.
Serial number 43x Stamped in white ink on the left end of the upper channel of the rack; the right digit of the number is obscured.


overall: 7 3/8 in x 26 in x 12 1/2 in


The rack is built around two identical frame members consisting of a piece of heavy metal that is bent up along one side and down along the other, resulting in an 'N'-shaped channel with a 1.75" bend up, a 2.25" horizontal surface, and a 0.625" bend down. Two of these, oriented in opposite directions, are held together with ten 24-contact edge connectors into which two-tube modules are inserted. Two 11-position screw terminal strips also span the two channels on the right side of the front. Twenty round holes to accommodate BNC connectors are drilled along the front of both channels; however, not all the holes are populated. On the back of the rack, phenolic boards with several rows of solder terminals are mounted to the horizontal sections of each channel, and another phenolic board with two rows of solder terminals is mounted perpendicular to the bottom one. Two 5-position screw terminal strips are mounted on the left side of the back of the rack, and one 4-position screw terminal strip is mounted to the bottom of the left end of the bottom channel.

About 7 long bus wires are connected to pins of the module sockets to supply common signals and voltages. The two horizontal boards are also wired with two busses each. The vertical board attached to the bottom horizontal board hold the passive components of the rack. Wiring is point-to-point between the solder posts of the boards and the terminals of the module sockets. Some of the wiring terminates at the screw terminal strips. Many of the external wires connected to the screw terminal strips have been cut.

Five brackets that hold two neon lamp sockets each are mounted to the upper phenolic board. Each pair of sockets has a red lens and a clear lens. The brackets are labeled with plastic white-on-black labels with the digits '6' through '10,' and the white lamp lenses are labeled "0" and the red one labeled "1."

There are six BNC connectors in the 20 holes along the top of the rack; a cutoff BNC cable is attached to each one. Thirteen of the holes along the bottom of the rack are populated with BNC connectors. Two of the connectors has a BNC cable that has been cut off attached, and the rest have a BNC tee, a terminator, and a cut-off BNC cable attached.

All module locations are occupied by 2-tube plug-in modules, and they each have a tag attached with handwriting in pencil. The module model, serial number, and tag inscription are, from left to right: FF# 1021, "E15-7-1"; GT BA# 2160, "E15-7-2"; FF# 979, "E15-7-3"; GT BA# 257, "E15-7-4"; FF# 958, "E15-7-5"; GT BA# 238, "E15-7-6; FF# 930, "E15-7-7; GT BA# 225, "E15-7-8; FF# 1024, "E15-7-9; and GT BA# 285, "E15-7-10".




Gift of Compaq Computer Corporation

Lot Number