TM 9-4910-700-14 & P
6.
Connect the loop and adjust
3.
Adjust the repetition rate
R14 on the test unit for an
using the electronic counter
exact indication of 5000RPM.
to 8.333PPS (1000RPM). Re-
connect the loop to the out-
7.
Repeat step 2 and adjust the
put of the generator.
repetition rate for 20.833PPS
Reconnect the
(2500RPM).
4.
Adjust R16 for an exact
The meter should read
loop .
1000RPM indication on the
between 2350 and 2650 RPM.
meter under test.
5.
Repeat step 2 and adjust
the repetition rate to
41.66PPS (5000RPM).
4-5. TROUBLESHOOTING. Troubleshooting
4-6. REPAIR, Repair procedures for the
may be best accomplished by use of the
test set are limited to replacement
following procedure.
of defective components.
Tachometer Troubleshooting.
a.
Replacement of Board Mounted
a.
Table 4-3 lists some symptoms
Electronlic Components. W hen re-
placing parts on circuit boards,
tachometer. Locate the symptoms
it is recommended that a solder-
and follow the indicated fault
ing iron of 40 watts or less be
isolation procedures.
used. After removing the com-
ponent, clear the solder out of
b.
Dwell Meter and Points Resistance
the holes in the circuit board
Troubleshooting. Table 4-4 lists
before re-inserting. Remove flux
symptoms an probable defects for
residue with Freon TMC or Tri-
the dwell meter and points resis-
chloroethane after re-soldering.
tance circuit.
b.
Replacement of Chassis Mounted
Components. C hassis mounted comp -
orients should be replaced using
proper mechanical assembly pract-
ices . Be sure to retain all mount-
ing hardware when replacing parts.
Refer to chapter 5 for parts
listing.
4-4
