The meter, a high torque Alnico movement, is protected against burn-out by a meter fuse. The fuse will not blow on overloads which are not sufficient to damage the meter. If the meter does not operate on any range, the fuse should be replaced with a-1/16 ampere little fuse, Cat. #361.062. IT IS MANDATORY THAT THIS FUSE NOT BE REPLACED WITH ANY OTHER VALUE THAN l/l6 AMPERE. If this precaution is not taken,an error may be introduced or worse,the meter may be,burned out* Provisions are made for testing all types of receiving tubes including octal, non-octal, local, cold cathode, miniature, sub-miniature, and ballast tubes. The circuit is so arranged that all tests are made under voltages and loads specified by the Radio Manufacturers Association. The special "Dynoptimum” tube checking circuit is comparable to those found in far more expensive tube testers. All multi-purpose tubes have individual listings for each of the various sections which are tested separately. Hot and cold shorts between all elements are rapidly checked. Microphonics or noise in a tube due to loose elements can be detected by using the accessible phone jack provided on the front panel, labeled NOISE.