Dismantling
45
NOTE:
The two screws at the bottom of the front panel, adjacent to the jack sockets,
are secured to the main chassis with nuts.
(3) Carefully withdraw the front panel and unsolder the connections to the meter
and speaker switches; alternatively, the number of wires to be unsoldered can be
minimized (loudspeaker only) by removing the seciring nuts on the SPEAKER
and METER switches. The panel may now be completely removed.
NOTE:
When replacing the B.F.O. NOTE control knob, ensure that the identification
mark on the saft is uppermost and that the pointer indicates zero when zero-beat
is obtained.
(4) Re-assemble in the reverse order.
NOTE:
When removing the control knobs secured by a hexagon collet insert the collet
must be shot loose from the spindle by a slight knock on the chromed centre of
the control knob.
Second Variable Frequency Oscillator
3.
(1) Remove the bottom cover.
(2) Unsolder the three connections on the 4-way tag strip, adjacent to the terminal
strip, situated in compartment 11 (see fig. 15: Key to Under-chassis Layout).
(3) Remove the front panel: see para.2. above.
(4) Withdraw the Crystal Calibrator Unit by slackening the two knurled nuts, dis-
connecting the coaxial cable and unplugging the unit.
(5) Unbolt the cable cleat securing the dial light cable.
(6) Unclip the lampholder.
(7) Disconnect the coaxial cables.
(8) Remove the screws securing the Megacycles dial to the boss and withdraw the
dial.
NOTE:
Do not unscrew the boss from the shaft. Unscrew the two unit retaining screws
on the top of the chassis and one retaining screw from the underside of the main
chassis in compartment 11.
(9) The v.f.o. may now be withdraw vertically. When servicing this assembly, clean
the wormwheel and the split gear on the ganged capacitor shaft with carbon-
tetrachloride, then apply with a brush, to the wormwheel only (Fig.11), a thin
coating of Molybdenum Disulphine grease (Rocol ”Molypad”).
(10) Re-assemble in the reverse order.
Renewal of Film Tuning Scale
NOTE:
Great care must be taken when feeding a new film into position to avoid twisting
or buckling.
Removal
4.
(1) Rotate the KILOCYCLES scale to the limit of its travel at the 1000 kc/s end of
the scale. Apply the scale lock.
(2) Remove the dial illuminating lamp and its holder.
Summary of Contents for RA-117
Page 1: ...Racal RA 117 Radio Receiver...
Page 24: ...Detailed Circuit Description 24 at maximum is the correct calibration maintained...
Page 32: ...32...
Page 70: ...Illustrations 70...
Page 71: ...Illustrations 71...
Page 72: ...Illustrations 72...
Page 73: ...Illustrations 73...
Page 74: ...Illustrations 74...
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