D4S (1968 to 1983)	Back	Up	Next
The D4S meter was a complete redesign of the D3S meter for a lower profile and lighter weight. This was accomplished by using a smaller disk and mounting the voltage and current coil assemblies separately on the frame. Unlike the previous models, the light-load adjustment on the D4S is accessible from the front. D4S meters made in 1983 (S/N 68,800,000 and up) used the same guide bearings introduced on the D5S meters and were just as prone to premature wear causing serious accuracy errors on light loads.	Photo by David Dahle