Troubleshooting - TM-9-4931-456-14-10067

4.2.7

(Cont'd)

The +180 V supply uses a half wave rectifier and series regulator. The regulator uses the +5 V supply as

its reference and, therefore, the +5 V source must be properly calibrated prior to adjusting the +180 V

source. R2 adjusts the +180 V supply to +180 V 5 V. The voltage out of the transformer is deliberately

greater than 180 V which enables the series regulator to essentially subtract from this potential the

necessary amount to deliver the required +180 V between pin 5 of P1 and COMMON.

Both voltage supplies can withstand momentary output shorts due to the inclusion of overload protection

transistors Q2 and Q4; however, due to internal heating, excessive damage may be sustained by

prolonged shorted output.

The power transformer T1 and filter capacitor C102 are located on the chassis separate from the Power

Supply Regulator component board. For details on the transformer connections, see Dwg. #0103-5005-

04.

4.3

Troubleshooting

The reliable performance of integrated circuits virtually eliminates the need for maintenance programs, and with

the "600" series counters, plug-in integrated circuits make even the occasional maintenance requirement a

simple procedure. Section IV of the manual has been constructed to enable the maintenance technician to

quickly isolate the trouble and identify the erring component. Because IC testers are expensive and not

universally available, it is recommended that a set of replacement units be available where maintenance is to be

performed. The standardization of components used throughout the counter greatly reduces the number of

components required and spare parts provisioning is thereby simplified.

Integrated circuits can be readily interchanged if one is suspected of being faulty. However, care must be taken

to assure proper replacement of the item. First, check to make certain that the replacement unit is of the correct

type as indicated on the appropriate parts list. Second, check proper orientation of the IC by making certain that

the notched end of the IC is inserted at the end of the socket exhibiting a beveled corner. Third, change IC's only

with the power OFF.

Many apparent failures in counters can be traced to incorrect signals or improper connections, rather than actual

component failure. If the counter fails to operate properly, double check all input signal levels against those

specified in the Specification Sheet, Section I, and make certain all controls are set according to the procedures

defined in Section III of the manual.

4-22