Component Replacement

Fig. 4-17. Preparation to remove the oscillator and tuner assembly.

b. Slide the oscillator tube out of the mounting flanges by

gently pushing the tube with a plastic or fiber dowel. See Fig.

c. Insert the new tube and slide into place. Do not bend

the two contact fingers for the filament buttons.

d. Replace the cover and secure all mounting screws.

Tighten the screws uniformly.

e. Refer to the Calibration section to calibrate the oscil-

lator and check its operation.

2. Band C oscillator tube replacement (V42)

The procedure to replace this tube is described and

illustrated in Fig. 4-20A and 4-20B.

Component Replacement

The physical size and shape of the replaced component

may affect the performance of the circuit, therefore it is best

to duplicate the original component as much as possible.

Parts orientation and lead dress should also duplicate those

of the original part since many of the components are

mounted in such a way as to reduce or control circuit capaci-

tance and inductance. After repair, the circuits of the instru-

ment may need recalibration.

Fig. 4-18. Replacing the mixer diodes.

4-14