GROUND RADIO BULLETIN NO. 52 JANUARY 27, 1954 COMMS. DEPT. L.A.D.
OHMITE 500 OHM CONTROLS
These controls are used in TMC-T (items 16 and 17) and 12ACX2 (item 40) 12GIX2 (item 38) equipment, and to some extent elsewhere.
George Masterson of the Ground Badio Shop indicates that erratic operation of these controls is sometimes caused by poor contact other than the resistance wire surface and the wiping carbon contact.
There is a moving contact arrangement down m the center of the control that completes the circuit from the carbon pickup on the arm to the center soldering lug for external wire connection to the control. This point sometimes gives poor contact, causing unsteady voltage control conditions.
The control can be disassembled by loosening the retaining nut around the shaft. The rotor will then drop out and the wiping contacts can be examined and cleaned for good electrical contact.
This in some cases will result in restoring the control to useful purpose, and provide additional economy of parts replacement.
STATION DRAWINGS
Station drawings are checked periodically during inspections, and corrections are made to cover changes that have occurred since the previous viewing.
Because considerable time elapses between such revisions, it will assist materially if all stations will correct their copy of the station drawing whenever a change is made, and forward the drawing to Miami. A new print will be made incorporating the change, and the corrected drawing will then be returned to the station.
Corrections can be made in pencil and can be rough as long as all details are shown clearly. Even the most minor changes should be included since these tend to grow from time to time until considerable differences result in the station copy as compared to the Miami file copy.
FORM 9211—2107
