Turret attenuators
In a Turret attenuator, individual R/C attenuator elements are rotated within a cylindrical housing whereas the external contacts stay stationary.
They were used in the Type H, Type Z, 516, and 1121 and are known to give trouble in the form of intermittent electrical continuity at the contacts.
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Turret attenuator of a 1121
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Type Z attenuators circuits