Page 4 PH I LCO
Service Bulletin No. 194
Adjusting Compensating Condensers
For adjusting compensating or padding con-
densers in Model 118, an accurately calibrated
signal generator covering the broadcast range of
frequencies is required and also a crystal con-
trolled signal generator for the high frequency
adjustments. For the former we suggest the
Philco Model 024 Signal Generator and for the
latter the Model 091, Crystal Controlled high
freq.uency signal generator. The actual adjusting
calls for a special insulated hex wrench and
insulated screwdriver. Philco Part No. 3164
·Fibre Wrench and No. 27-1159 Screwdriver are
·recommended. An output meter is also required,
.for connection to the receiver.
I. F. ADJUSTMENT-The I. F. (intermedi-
ate frequency) of Model 118 is 260 K. C.
Remove the grid clip from the top of the 6A7
tube and connect the shielded antenna lead from
the Signal Generator to the cap of this tube.
Connect the ground lead of the Signal Generat or
to the ground post of receiver. Connect the
output meter to the primary terminals of the
output transformer of receiver . Set the wave-
band switch at the left position (standard broad-
cast).
Set the wave switch on the Signal Generator at
260 K. C., and the dial of the receiver at 550.
Turn on the set (volume full on), and the Signal
Generator. Now adjust the 1st I.-F. Primary and
Secondary condensers (Nos. @)and @ in Fig. 3)
and the 2d I. F. primary and secondary con-
densers (®and @) to give maximum reading on
the output meter. The I. F. primary condenser
is adjusted by turning the screw on top of the
I. F. transformer and the secondary is adjusted
by turning the nut. The I. F. transformers
are in the smaller metal "cans". The screw and
nut are reached through the hole in top. If the
:r;ieedleon the output meter goes off the scale,
turn down the "attenuator" on the Signal
Generator until a lower reading is obtained.
Note: In early production the 1st I. F. com-
pensating condensers only are adjusted as
described above. Part @ is not used. The 2d
I. F. primary ® is an 04000A condenser reached
and adjusted through hole in top of chassis near
the 42 driver tube.
WAVE TRAP - Remove antenna lead from
grid cap of 6A7 tube and attach it to antenna
post on set. Replace cap on 6A7 tube. With
Signal Generator still operating at 260 K. C.,
adjust wave-trap condenser (© in Figs. 3 & 4)
so as to get MINIMUM reading in output meter.
This adjustment is made from underneath the
chassis.
ANTENNA, DETECTOR AND OSCILLA-
TOR H.F. (Broadcast)-These condensers Nos.
!J), @, and ®, are located on top of the tuning
condenser gang, adjustment made by means of
the fibre wrench . Set the signal generator at 1500
K. C., tune in the signal at 1500 on dial and
adjust these condensers in the order given, to
give maximum output reading. !J) is located on
the section nearest the front and @ on the center
section.
OSCILLATOR-LOW FREQUENCY-This
is condenser @ (see Figs. 3 and 4) located under-
neath chassis and accessible from underneath.
Use the fibre wrench. Set signal generator switch
at 600, tune in the signal at 600 on the dial and
adjust condenser to maximum.
ANT. AND OSC. H. F.-SHORTWAVE-
The crystal controlled signal generator is used
for these adjustments. These are condensers ®
(Ant. H. F.) and @ (Osc. H. F.) located under-
neath chassis, and adjusted from underneath.
The fundamental frequency of the Philco Model
091 crystal controlled signal generator is 3600
K. C. or 3.6 megacycles. The third harn;10nicof
this is 10.8 M. C. Turn the waveband switch
of the set to the right and the dial to just below
11 M. C. The 10.8 harmonic should be picked up
here and the two condensers should be adjusted
to give maximum reading on the output meter,
on this signal.
USE PHILCO REPLACEMENT PARTS AND TUBES FOR EVERY MAKE RADIO.
June, 1934
Printed in U. S. A
GET COMPLETE CATALOG FROM YOUR DISTRIBUTOR.
PHILCO RADIO & TELEVISION CORPORATION
Service Department
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