Model 738AR

TM 11-6625-1614-15

Model 410C

Section V

Paragraphs

5-1to 5-11

SECTION V

MAINTENANCE

5 - 1 . I N T R O D U C T I O N .

 

5 - 9 . M e c h a n i c a l M E T E R Z E R O .

5-2.

This section contains

maintenance procedures

 

 

 

 

a. Turn instrument on.

Allow at least a 20

for

the Model 410C Electronic Voltmeter.

minute warm-up period.

 

 

5-3.

TEST EQUIPMENT

REQUIRED.

 

 

 

 

 

 

5-4. The test equipment required to maintain and adjust the Model 410C is listed in Table 5-1. Equipment having similar characteristics may be substituted for items listed.

5-5. PERFORMANCE CHECKS.

5 - 6 . The performance checks presented in this section are front panel operations designed to compare the Model 410C with it’s published specifications. These operations may be incorporated in periodic maintenance, post repair and incoming quality control checks. These operations should be conducted before any attempt is made at instrument calibration or adjustment. During performance checks, periodically vary the line voltage to the Model 410C, ± 10% on either 115v or 230 v operation. A 1/2 hour warm-up period should be allowed before these tests are conducted.

5-7. ALTERNATE VOLTAGE SOURCE.

5-6. Should it be necessary to use the

Voltmeter Calibrator to conduct these Performance Checks, the arrangement described in Figure 5-1will provide the necessary voltage values required. How- ever; the Model 738BR Voltmeter Calibrator is the preferred instrument for these operations.

b. Turn voltmeter off, and allow 30 seconds for all capacitors to discharge.

c.Rotate mechanical zero-adjustment screw on front panel clockwise until pointer reaches zero, moving up scale.

d.If for some reason the pointer should over- shoot zero, repeat step c until desired results are obtained.

e. When pointer has been positioned at zero, rotate zero-adjust screw slightly counterclockwise to free it. If meter pointer moves to the left during this action, repeat steps c and e.

5-10. DC VOLTMETER OPERATION.

5-11. ACCURACY CHECK (DCV).

a. Set the Model 410C FUNCTION SELECTOR to the +DCV position; RANGE switch to. 015 V .

Connect Model 410C DCV and COM cables to the

Voltmeter Calibrator Model 738BR) output terminals.

Figure 5-1. Alternate Voltage Source

01556-2

5-1