CHAPTER 5 OVERHAUL STANDARDS

TM 11-5840-270-24-1

CHAPTER 5

OVERHAUL

STANDARDS

5-6. Pointer Stops Test

5-1. Scope

a. Pointer stops shall permit deflection of

The tests outlined in this standard are designed to

horizontal and vertical pointers to end dot without

measure the performance capability of repaired

interference. Pointer shall deflect slightly past end

equipment. Equipment that is to be returned to

dot, or approximately 10% beyond full scale

stock should meet the standards given in these tests.

deflection (para 4-23).

Refer to chapter 4 for test procedures.

b. With an overload current of 750 microam-

5-2. Applicable References

pere applied to either pointer, in either direction,

a. Repair Standards. Applicable procedures of

pointer will deflect to stop. Gradually and evenly

the depot performing this test and the general

reducing current to 130 microampere will cause

standards for repaired electronic equipment given

pointer to leave stop without tapping or vibrating

in TBSIG 355-l, TB SIG 355-2 and TB SIG 355-

the instrument. Break away current shall not be

3 form a part of the requirements for testing this

less than 130 microampere (para 4-23).

equipment.

5-7. Pointer Clearance Test

b. Modification Work Orders. Perform all

modification work orders applicable to the ID-48A

With current applied to any combination of

before making the tests specified. DA PAM 310-7

mechanisms no pointer will interfere with operation

of any other pointer at any position or deflection.

lists all available modification work orders.

5-8. Sensitivity Tests

5-3. General Test Requirements

a. Horizontal and vertical pointers shall deflect to

The tests indicated in this chapter should be

end dots, either side of center, with 150 7 . 5

conducted at a temperature of approximately

25C. (77 oF.). The Indicator should be lightly

microampere applied to appropriate pins of

connector J1 (para 4-21).

tapped or vibrated when taking readings except

b. Horizontal and vertical flags shall leave stops

where otherwise stated.

with 125 6.0 microampere applied and shall be

5-4. Terminal Resistance Test

concealed by mask when 250 12.5 microampere

Resistance of each mechanism circuit shall be 1000

are applied (para 4-22).

30 ohms, measured at connector J1 terminals

5-9. Response Time Test

(para 4-20).

The time required for the horizontal or vertical

5-5. Balance Test

pointer to reach 90 percent of its deflection

Glide path and localizer pointers shall be aligned

distance, counted from the instant current is ap-

with appropriate row of dots when in normal

plied shall be 1.2 seconds maximum (para 4-24).

vertical mounting position. Rotating Indicator 90

left and right and to dial-upward positions shall not

cause pointers to indicate off dot furthest from

pointer (para 4-17).

5-1