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6.5 Mechanical Construction(Continued
from
page 11)
be made such as replacement of the range
switch, it is necessary first to remove the
complete R-F unit from the receiver. To
do this the following procedure should be
observed:
(a) Remove the chassis and panel from
the cabinet by removing the four
panel mounting screws and sliding
the chassis forward out of the
cabinet.
(b) Remove the knobs by means of the
small wrench held in the spring clip
on the right hand side of the chassis.
This wrench fits the set screws in all
knobs except the main tuning knob.
For this knob use an ordinary small
screw driver.
(c) Remove the panel by removing the
eight nuts with which it is held to
the support brackets.
(d) Remove the large cover from the top
of the R-F unit, by removing the four
knurled nuts with which it is sup-
ported.
(e) Remove the small cover from the tun-
ing condenser, by removing the
eight knurled nuts with which it is
supported.
(f) Remove the dial light sockets where
they are clipped on to the tuning unit.
(g) Remove the antenna trimmer shaft
extension by loosening set screw in
coupling with same wrench as used
above for knobs.
(h) Remove support bracket from fly-
wheel tuning shaft.
(i) Remove main dial, vernier dial, and
flywheel by loosening set screws with
same wrench as used for knobs.
(j) Disconnect the eight leads which con-
nect the R-F unit to the main base.
These leads are as follows:—
(i) Two on the antenna terminal
board (blue and black).
(ii) One on number 7 pin of
the 6V6GT/G output valve
(brown).
(iii) One on terminal E of the
crystal load circuit (yellow).
(iv) One on terminal E of the first
I-F Transformer (red).
(v) One on terminal F of the first
I-F Transformer (blue).
(vi) One on pin 6 of the second I-F
valve (green).
(vii) One on pin 7 of the second I-F
valve (brown).
In addition, the by-pass condenser
which grounds to the R-F unit near
the second I-F valve must be dis-
connected.
(k) Remove eleven screws which hold
R-F unit to main base. Three of these
are on under side of chassis along the
front edge. The other eight are re-
moved from the top.
(I) The R-F unit may now be removed
from the bottom by lifting up first
the rear of the R-F unit and sliding it
hack out of the opening. After the
unit has been repaired it may he re-
assembled by following the above
procedure in reverse order.
[14)
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