Does anyone know how to adjust the discharge rate of a Shaffner NSG 505 HF-Test Generator, circa 1970's? A spark gap is placed on a rotating disk mounted on an AC motor shaft inside the unit and it is supposed to close at a rate of 400Hz. The output pulses, which individually look quite good as far as amplitude and the 1 MHz ring characteristics are concerned, are at a rate of only about 57 Hz as measured on a scope at the pulse monitoring output. According to the manual,the rate can be adjusted from 400 Hz to 200, 100, or 50 Hz. by mechanically removing contacts on the rotating disk. However, the disk has all contacts installed, which means it should be discharging at the default 400 Hz rate. Any insight into why I am only seeing a discharge rate of 57 Hz on a scope? Although I don't have any means to measure the speed of the motor, it seems to be operating normally. Is there some other adjustment internally that I can make?
Thanks. Jim Hulbert Pitney Bowes
