| Van Norman CP-468/U Beam Switching Counter | |
| Written by AnubisTTP on 2018-09-25 |
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The Van Norman Industries CP-468/U counting module is an obscure magnetic beam switching tube counter, which is dominated by a large Burroughs BD-301 ten position counting tube installed prominently in the center of the device. Magnetic beam switching tubes are complicated vacuum devices, which contain a ring of targets surrounding a central electron beam that can be 'bumped' from target to target with controlled pulses. Such tubes are vulnerable to external magnetic fields; the BD-301 tube used in this device is protected by a large cylindrical mu-shield to block external magnetic influence. This module also has two unpopulated 9 pin tube sockets, both marked for 5814A tubes, as well as a number of passive components on a PCB mounted below the magnetic beam switching tube. This module is rated for a maximum counting speed of 100khz and has a front mounted 12 pin edge connector for attachment of an external Nixie tube display.
Van Norman Industries CP-468/U beam switching decade counter module.
From the backside the spade resistors for the Burroughs BD-301 beam switching tube are clearly visible.
The driver board for this counter contains two neon bulbs as well as a number of passive components.
Van Norman CP-468/U counter schematic.
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