TM 9-4910-700-14 & P
4-4. ADJUSTMENTS. Adjustments are used
d.
to calibrate the test set to correct
for minor drifts due to component
1. Connect equipment per figure
aging or replacement. It should not
4-2. Set unit under test to
be necessary to make adjustments at
1000 RPM.
less than six month intervals, unless
components have been replaced.
petition rate of 16.66pps
a.
(1000ppm), a width of 10 micro-
seconds, and 20 volt amplitude.
1.
Verify the repetition rate
Set the ground switch to -
and connect the dwell lead
using the electronic counter.
to the -12V lead.
3. Unit under test should read
2.
Set the dwell switch on the
between 970 and 1030rpm.
unit under test to the 4 lobe
position and adjust R26 for
a full scale (90) indication
83.33pps (5000ppm).
of the DWELL meter.
5. Unit under test should read be-
Set the DWELL switch on the
3.
tween 4850 and 5150rpm.
unit under test to the 8
lobe position and set R28
for a 45 indication on the
41.666pps (2500rpm). Meter
DWELL meter.
should read between 2350 and
2650rpm.
4.
4-1. Leave unit under test
4-3. CLEANING AND LUBRICATION. Cleaning
set on 8 lobe position.
procedures are limited to the following.
No lubrication of the test set is re-
quired. Oils, greases, and other lub-
5.
20 volt pulse at 100Hz rep-
ricants are not to be introduced into
etition rate and 5 milli-
the interior of the test set.
second width,
Exterior Cleaning. The exterior
a.
Adjust repetition rate to
6.
of the test set can be cleaned
with a mild solvent and a soft
exactly 100Hz and 5 milli-
second width using electronic
rag. Do not use abrasive clean-
counter. This corresponds
ers,
to an engine RPM of 1500 and
a dwell of 22.5. The meter
b.
Interior Cleaning. Interior clean-
under test should read be-
ing should only be performed
when the test set has undergone
tween 20.7 and 24.3.
7.
Switch the unit under test
tended usage.
to the 4 lobe position. The
Remove the test set panel
meter should now read be-
1.
tween 42.3 and 47,7.
assembly from the case
b.
2.
Carefully clean the circuit
board, exterior of the
1.
Connect equipment per figure
4-2. Set unit under test
switches, etc. , using a cot-
to 1000 RPM.
ton swab and a mild solvent.
Be sure that any residue
Remove the loop across the
from the swab is removed.
2.
its output for a 10 micro-
Re-assemble the test set.
3.
second pulse width at an
amplitude of 20 volts.
4-3