Raymond Mod II Control Boxes

Part II

Last time we discussed the basic parameters of the Raymond Mod II black box controls. This month I would like to share with you some important test points and adjustment locations. When diagnosing any system it is extremely helpful to have accessible test point locations in order to measure certain voltages. The Raymond Mod II system has sixteen (16) test point terminals located on the mother board. In order to access these test points, simply remove the bottom control box cover. Some of these test points require an oscilloscope to monitor the SCR pulses, while other points are simple D.C. measurements. The following table gives the point of access and its system monitoring point.

Test Points Found On the Mother Board

Some quick explanations may be in order to go along with this chart. M speed is Raymonds terminology for 1A or bypass operation. The drivers mentioned are SCR drivers which when turned to the "ON" state apply a negative to the contactor coils in order to energize that specific coil. VPG stands for Variable Pulse Generator and PD stands for Power Driver.

Control adjustments are always necessary to fine tune the vehicle for specific operations, or simply the operators preferences. The adjustment potentiometers are 20 turn pots which are accessible from the mother board side of the control box. A 20 turn pot requires 20 full revolutions to get from one end to the other. All adjustments are user friendly except two, which should only be setup by a suitable repair facility. These two adjustments control the pulse width and overall frequency setting of the control system. To accurately set these parameters an oscilloscope is required. Improper adjustment of these controls may render the system inoperable. The following table designates the adjustment location and function controlled by that adjustment.



Robert Meyers