GROUND RADIO BULLETIN NO. 36 - DECEMBER 12, 1951 COMMS. DEPT. L.A.D.
4-250A TUBES
Fault Shaker Bulletin No. 34 September 12, 1951, mentioned this tube in a pre-liminary fashion regarding the operation, failures, etc.
Since then, failures have begun to increase according to line station reports. This is natural because more tubes are now in use, and many have been in use for a considerable number of hours. Operation continues good with this tube, and all stations in the Division are now using the ij.-250A except Guatemalan stations and Brownsville, which will be converted shortly.
Some stations where tube failures have occurred have not sent in the Service Sheet supplied by the manufacturer with each tube* Please be sure that this sheet is properly filled out and forwarded to the Ground Radio Engineer whenever a tube is taken out of service.
EQUIPMENT FUSES
Reports indicate that in some cases equipment at line stations is being improperly fused.
Information in particular on NC-2-40 receivers and EKV panels discloses that either too large size fuses are being used, or that the size varies considerably between units.
Consulting the instruction book and maintenance manual will always supply the correct fuse data, and the values designated should always be used except in temporary cases where the right fuse may be cut of stock.
Generally, equipment is fused for protection, and the value of the fuse is calculated to provide this protection before damage to the unit. Departing from the specified value defeats this purpose of the fuse and is conducive to equipment failure and possible damage.
In the case of NC-2-40 receivers and EICV panels, the correct fuse is a 2 ampere type 3AG. Please check your equipment for correct fusing, and see that sufficient quantities of the values needed are in stock.
