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Ampex Nagra VPR-5 Restoration Tipps

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Forum » Radios and other type of sets (Physics) etc. » RADIO MODELS DISPLAYED » Ampex Nagra VPR-5 Restoration Tipps
           
Hubert Eisner
 
 
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03.Aug.17 10:25
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If you ever come across the repair of the Ampex Nagra VPR-5 be careful not to just switch it on to see what happens …

For whatever reason, the friction brakes inside the supply- and take-up reel motor assemblies were made from some early silicon material that changed to sticky glue as the decades went by, effectively braking both motors to a standstill. As removing the sticky stuff and replacing it by some other sticky stuff would just open a Pandora’s box, a layer of thin coated plastic sheet does the trick. Polyethylenterephthalat (PET) is the raw material for readily available, silicon-coated plastic sheets with typical thicknesses from 1 to 800 µm.

It is recommended that you do not start the VPR-5 without checking first that the motors move freely. The electronics might break down during the brief period of time between the motors trying to run and the sensors recognising the error and switching off the current. If this happens more than once, damage is unavoidable.

Fortunately, Ampex and Nagra supply ample documentation and each(!) cable is numbered(!). All you need (or get during the process) are strong arms (the documentation folders are heavy) and good eyes (the size of the numbering on the cables is around 1/256th of an inch).

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