|
The CRT anode voltage is adjustable by means of R905. This control is accessible through the top perforated shield of the module. A hex tool 0.1 inch non-metallic composition should be used for this adjustment. Nominal H.V. is 14.5 KV @ 0 beam current. Focusing may be set by means of R909. This control is accessible through the side shield of the module. It is a small flat blade (0.125")/ screwdriver adjustment. The focus voltage is adjustable over the range of O to + 400 volts, and should be set for best overall definition. When replacing the H.V. module, make certain that the CRT anode is safely discharged to ground through a 10k Ohm resistor before removing the anode cap. |
Typical input current from the nominal 38V DC supply for a normal operating, unloaded H.V. module is 0.4 amp. In- put current will increase with loading and higher than nominal 14.5 KV H.V. This line is fused by F102 located on Deflection Amplifier Board. Under a load of 100 ua, H.V. should not change by more than 300 volts from 14.5 KV. Limit the brightness level on CRT such that beam current should not exceed 100 ua. To do otherwise will result in poor H.V. regulation. The 90V line should be capable of supplying 25 ma out- put current with good regulation. The focus and G2 voltages are capable of only very low current drain; they are potential voltages only. |