TM 5-2420-231-23-1
0019
Table 1. Tachometer Does Not Function or Is Inaccurate.
0019
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Tachometer Does Not
Test Step 1. Inspect Alternator,
Function or Is Inaccurate
Alternator Pulley, Drive Belt, Drive
Belt Tensioner, Alternator Cables,
and Verify Alternator Indicator
Operation.
1. Inspect the alternator mounting
Alternator Mounting and Bracket
bolts (Figure 1, Item 1 and 7) and
Bolts OK - Proceed to step 2.
mounting bracket bolt (Figure 1,
Alternator Mounting Bolts or Bracket
Item 3) (WP 0153).
Bolt Loose - Tighten mounting bracket
bolts (WP 0153).
Proceed to Test Step 4.
2. Inspect alternator mounting
Alternator Mounting Bracket OK -
bracket (Figure 1, Item 2) for
Proceed to step 3.
cracks or damage (WP 0153).
Alternator Mounting Bracket
Cracked or Damaged - Replace
alternator mounting bracket (WP 0153).
Proceed to Test Step 4.
NOTE
Note routing of drive belt to aid in installation.
3. Remove drive belt (Figure 1,
Drive Belt OK - Proceed to step 4.
Item 4) (WP 0095) from machine
Drive Belt Damaged, Stretched,
and inspect drive belt for the fol-
Glazed, Worn, or Greater Than Four
lowing:
Cracks Per Inch (25.4 mm) - Proceed
to step 8.
a. stretching
b. damage
c. glazing
d. wear
e. more than four cracks per inch
(25.4 mm)
4. Inspect alternator drive pulley nut
Alternator Drive Pulley Nut OK -
(Figure 1, Item 5).
Proceed to step 6.
Alternator Drive Pulley Nut Loose -
Proceed to step 5.
5. Remove alternator drive pulley
Alternator Drive Pulley OK - Proceed
(Figure 1, Item 6) (WP 0153) and
to step 7.
inspect alternator drive pulley and
Alternator Drive Pulley Worn or
alternator drive shaft (Figure 1,
Damaged - Replace alternator drive
Item 9) for wear and damage.
pulley (WP 0153).
Proceed to Test Step 6.
6. Inspect alternator drive pulley
Alternator Drive Pulley OK - Proceed
(Figure 1, Item 6) for wear and
to step 7.
damage.
Alternator Drive Pulley Damaged -
Replace drive pulley (WP 0153).
Proceed to Test Step 6.