Artifact Details


Whirlwind vacuum tube module rack

Catalog Number



Physical object


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 lower one of these. 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 lower horizontal board holds 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.

Seven BNC connectors are mounted in the 20 holes along the top of the rack; one of these has nothing attached; five have a cutoff BNC cable attached; and one has a BNC tee, a terminator, and a cutoff cable attached. Five of the holes along the bottom of the rack are populated with BNC connectors; four have a cutoff BNC cable attached; and one has a BNC tee, a cutoff BNC cable, and a terminator attached.

All module locations are occupied by 2-tube plug-in modules; all have a tag attached with handwriting in pencil. The module type, serial number, and tag inscription on each are, from left to right: PS 99, "E15-3-1"; BA BA# 16, "E15-3-2"; BA BA# 270, "E15-3-3"; BA BA# 76, "E15-3-4"; BA BA# 134, "E15-3-5"; BA BA# 196, "E15-3-6"; BA BA# 272, "E15-3-7"; BA BA# 369, "E15-3-8"; BA BA# 10, "E15-3-9"; and the module on the far right doesn't have a model number, "E15-3-10". Two of the modules are missing one tube.



Identifying Numbers

Other number 01816 Stamped in blue ink on a white label stuck near BNC connector J8-2 on the top channel of the rack.
Other number 02483 Stamped in blue ink on a white label stuck near BNC connector J6-3 on the bottom channel of the rack.
Other number E15-3 Written in ball point pen on a sticker stuck to the left end of back of the upper channel of the rack.
Serial number 439 Stamped in white ink on the left end of the upper channel of the rack.


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




Gift of Compaq Computer Corporation

Lot Number