TM 55-1930-209-14&P-12
13.
Check the centering of the coil unit. Adjust if necessary by repeating Step 12.
14.
Run the driver unit to check for rubbing between the coil and magnet units. A clear tone indicates absence of
interference.
15.
Install the driver unit in the fog horn.
4.2 Trouble Shooting
4.2.1 Horn does not blow.
1.
Check battery voltage.
2.
Check voltage and polarity at terminals one C+) and four (-) on oscillator 9010-0144.
3.
Check for negative coded voltage on terminals 2 (+) and 5 (-) This voltage should correspond to characteristic. If
no voltage appears, program timer is inoperative.
4.
Measure AC voltage between oscillator terminals 6 and 7, During "on" period of program timer, this voltage
should be approximately double the value of the battery voltage bu AC rather than DC.
5.
If no voltage is obtained between 6 and 7, check the fuse in the oscillator. If the fuse is blown, replace it with a
AGC-5 Buss or equivalent (API Part. No. 4035 0022). If the new fuse blows, it is probable that a transistor Q7
or Q8 is defective. Replace the oscillator or install a new matched pair of 2N3612 transistors . When transistors
are replaced, be sure that a light coating of silicone grease is applied to the insulating washers.
6.
If the fuse is not blown, disconnect a lead from either terminal 6 or 7 and recheck the AC voltage between 6 and
7. If this
Form No. 6310 0238
