TM 11-6625-1633-45
Figure 3-11. Terminal Board TB4-A3, parts location diagram.
Point of measurement
Normal indication (ohms)
Isolating procedure
If resistance is zero, check for shorted
About 950K
Between test points A4TP1 and
filter capacitor C45 (fig. 3-2). Re-
A4TP4 (fig. 3-8).
place defective component.
If resistance is zero, check for shorted
0 to 100 K depending upon adjust-
Between pins 1 and 3 of klystron
filter capacitor A3C1 (fig. 3-11).
ment of GRID BIAS potentiometer
A4V1 (fig.. 5-8)
Replace defective component.
A3-R11. MODULATION selector
switch S2 may be in any position
If resistance is zero, check for shorted
except OFF.
filter capacitor C38; if resistance is
About 26K with negative probe on
Between test points A4TP5 and
low (about 4K), check for shorted
test point A4TP5. About 35K with
A4TP9 (fig.. 3-8).
filter capacitor C39. Replace defec-
negative probe on test point A4TP9.
tive component.
If resistance is zero, check for shorted
About 140K
Between test points A4TP1 and
filter capacitor C56 or shorted coils
A4TP10 (fig. 3-8).
of relay K2, K3, or K4. Replace de-
fective component.
3-11
