TM 11-6625-2709-40
2.8. Troubleshooting Chart.
Probable trouble
Proper
for improper
Correction
Procedure
Step
indication
indication
VOR/LOC 2A fuse (F2) is
Replace F2 with a 2-
Multimeter should
Connect the multi-
1
ampere fuse.
blown.
indicate 27.5 volts dc.
meter to the test
point located in the
ceter of the VOR/
LOC 2A fuse cap.
The following lamps
2
Set the megahertz
should light:
and kilohertz se-
lectors on the con-
trol unit to 108.00
a. If a break in the circuit
a. If LOC PWR and/or
a. LOC PWR and
MHz.
is present between
GS PWR lamps on
GS PWR lamps
aid box does not light,
on aid box.
P5-M and P2-A, make
either a break in the
resistance measure-
circuit is present be-
ments to find the break.
tween P5-M and P2-A/R
If no breaks are pre-
or switch S6A in the
sent, troubleshoot the
control unit is
control unit as de-
defective.
scribed in TM 11-
5826-226-34.
b. If VOR/LOC DC lamp
b. Replace DS10.
b. VOR/LOC DC
on test set does not
lamp on test set.
light, DS10 is faulty.
c. Measure the ac voltage
c. If 26 VAC PWR lamp on
c.
26 VAC PWR
at test point located at
aid box does not light,
lamp on aid box.
the center of the VOR/
VOR/LOC 1A fuse is
LOC 1A fuse cap. If 115
blown, relay K1 is
volts ac is not present,
defective, or trans-
replace fuse F1. If 115
former T1 is defective.
volts ac is still not pre-
sent, check for a de-
fective relay K1 by
measuring its coil re-
sistance (para 2-9). If
defective, replace re-
lay K1. Check for a
defective transformer
by measuring its re-
sistances (para 2-9).
Replace if defective.
d. Replace DS9.
If VOR/LOC AC lamp
d.
d. VOR/LOC AC
on test set does not
lamp on test set.
light, DS9 is faulty.
e. Measure the dc voltage
e. If GS DC lamp on test
e. GS DC lamp on
at the test point lo-
set does not light, either
test set.
cated at the center of
GS 1A fuse (F3) is blown
the G3 1A fuse cap. If
or GS DC lamp (DS11) is
27.5 volts dc is not
burned out.
present replace fuse
F3. If 27.5 volts dc is
present, replace lamp
DS11.
(Cont)
Change 1
