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USA Rotor NSA KL-7 PSU →
Operator maintenance kit
Each KL-7 cipher machine came with a set of supplies, spare parts
(tubes) and maintenance tools, packed together in a compact grey metal storage
case labelled: Operator Maintenance Kit. Like the machine, it was
distributed to the users by the United States
National Security Agency (NSA).
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The box measures 160 x 160 x 135 mm and weights approx. 2400 grams, depending
on the exact contents. It is painted in the same neutral grey
colour as the KL-7 itself and contains spare valves (tubes) and a tool to
extract the valves.
It also contains tools to clean the contacts of the KL-7 and its rotors.
It was very important to use the right materials as
– according to former KL-7 users – the machine faced a number of reliability
issues that were all contact-related. Apparantly, cleaning the contacts with
a soft cloth and a cleaning agent like alcohol, was not sufficient.
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Instead, the contacts of the rotors had to be cleaned by rubbing them over
a wooden block lined with cloth, that was supplied as part of the kit.
More serious contact problems were treated with an
ink eraser that was also
supplied. The transpartent cylinder that is visible in the image above –
stowed diagonally in the case lid – is a
moisturiser, or humidifier, for the
pre-gummed paper.
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- Contact cleaning eraser, Parapink Faber-Castell 701
- Finger-mount tape cutter
- Tube puller (2 sizes), a.k.a. Chinese Finger Trap
- 4 x 2D21 valve
- Dust brush
- Bristle 'tooth brush'
- Contact cleaning block, with spare cloth strip
- Set of lint-free cleaning cloths, CE87298
- Spare light bulb for 'Shift', General Electric NE-48
- Spare light bulb for 'Keyboard illumination', W313
- Moisturiser for pre-gummed paper tape
- Tube pin straightener (2 types, for 7 and 9-pin valves)
- Metal can of red coloured cleaner/lubricant
- Hex wrench
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From its introduction, the KL-7 had reliability issues, which were
mainly caused by contact problems of the rotors. As the spring-loaded
contacts at one side of each rotor are made of beryllium-copper (BeCu),
they easily oxidise and become non-conducting. Cleaning the contacts
with alcohol does not help, but rubbing them with the tools supplied
in the maintenance kit does.
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WARNING —
Although the percentage beryllium used in the contact is fairly low (0.5–3%),
you should be aware that it is a harmful carcinogen when inhaled or digested.
In general, dust containing beryllium – for example from sanding, grinding
or filing – should be avoided. In solid form, beryllium can safely be used [1].
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© Crypto Museum. Created: Sunday 09 August 2009. Last changed: Tuesday, 16 April 2024 - 10:04 CET.
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