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ALIGNMENT INSTRUCTIONS
PRE-ALIGNMENT INSTRUCTIONS
The High Voltage lead should be securely taped and kept away from the chassis.
Allow a 20 minute warm-up period for the receiver and test equipment.
Suggested Alignment Tools:
GENERAL CEMENT #8606, 8606L, 8282, 9295
WALSCO #2526, 2543, 2544, 2545
VIDEO IF ALIGNMENT
Connect the negative lead of a 6 volt bias supply to point <X> . Positive to chassis.
Connect the negative lead of a 15 volt bias supply to point <E> • Positive to chassis.
Connect the negative lead of a 7 volt bias supply to point <g> . Positive to chassis.
Connect the negative lead of a 7 volt bias supply to pin 2 (grid) of the Horizontal Blanking Amp. Positive to chassis.
Connect a clip lead from point <E> to chassis. Preset Sound Reject (R26) at 75% clockwise rotation. Preset Sound Adjust (R27) at 50% rotation.
Video IF shield must be in place during alignment.
DUMMY
ANTENNA
Direct
ii
„
..
"
SIGNAL
GENERATOR
COUPLING
High side to ungrounded
tube shield floating over
Mixer-Osc. (V202).
Low side to chassis.
..
"
"
"
SIGNAL
GENERATOR
FREQUENCY
43.8MC
(Unmod)
42. SMC
45.75MC
44.0MC
41. 25MC
47.25MC
41. 25MC
CHANNEL
4
"
..
"
"
"
"
"
CONNECT
VTVM
DC probe thru 10 K to
point \fy . Common
to chassis. Use nega-
tive scale.
"
"
"
"
DC pr*e thru 10K to
point <£> . Common to
chassis.
ADJUST
Al
A2
A3
A4
Mixer
Plate Coil
A5.R26
A6, R27
A7
REMARKS
Adjust for maximum deflection.
Use peak with cere
nearest printed board end of coil. Maintain VTVM
reading of 1. 5 volts by adjusting signal generator output.
"
"
Adjust for maximum deflection with peak at top end
of coil.
Adjust A5 and Sound Reject (R26) simultaneously
for MINIMUM deflection with slug away from chassis.
Reduce bias at point <^> if necessary for sufficient
indication.
Adjust for MINIMUM deflection with slug away from
chassis.
Increase bias at point <S> to -6 volts. Adjust A7 lor
MINIMUM deflection with slug away from chassis.
OVERALL VIDEO IF RESPONSE CHECK
9.
10.
11.
12.
13.
14.
Connect bias as under "Video IF Alignment":
Connect a . OOlmfd capacitor in series with a 180SJ resistor from pin 5 (Plate) of the 2nd Video IF Amp. to chassis with the resistor next to chassis.
Connect a lOOOmmf capacitor across the scope leads.
The Video IF shield must be in place during alignment.
Connect the DC probe of the VTVM to point <g> . Common to chassis.
(Use negative scale).
Use 10MC sweep unless otherwise noted.
DUMMY
ANTENNA
Direct
"
Fig. 4
SWEEP
GENERATOR
COUPLING
High side to ungrounded
tube shield floating over
Mixer-Osc. (V202). Low
side to chassis.
"
Across VHF antenna ter-
minals t h r u matching
network (Fig. 4).
SWEEP
GENERATOR
FREQUENCY
45MC
"
All VHF
Channels
separately
MARKER
GENERATOR
FREQUENCY
42.17MC
45.75MC
41. 25 MC
47.25MC
41.65MC
42.17MC
42.75MC
45.0MC
45.75MC
41.25MC
42.17MC
CHANNEL
4
"
All VHF
Channels
separately
CONNECT
SCOPE
Vert. Amp. thru de-
modulator probe (Fig
1) to pin 5 (plate) of
1st Video IF. Low
side to chassis.
"
Vert. Amp. thru 10K
to point
<g> . Low
side to chassis.
'•
"
ADJUST
REMARKS
Set sweep output for . 1 volt peak to peak on
scope. Retouch Mixer Plate Coil and A4 for
maximum gain and symmetry of response
similar to Fig. 2. Reduce the bias to -4
volts at point <§> if necessary.
Reduce bias at point <Q> to zero.
Retouch
A7 to place marker in trap notch as in Fig. 2.
Retouch A6 and R27 to place marker in trap
notch as in Fig. 2. Remove capacitor and
resistor load from 2nd Video IF. Increase
bias at point <§> to -6 volts.
Use 3 volts peak to peak on the scope. Re-
:ouch Al, A2 and A3 for response similar to
Fig. 3 with markers as shown. Al controls
the tilt, A2 affects 42. 17MC side of curve
and A3 affects the 45. 75MC side.
Connect
a . OOlmfd capacitor from point <§> to chassis
Retouch A5 and R26 to place marker in trap
notch if necessary. Remove . OOlmfd.
Decrease bias at point <^> to -3 volts.
SLIGHTLY retouch Al, A2 and A3 to correct
or any overall tilt that is approximately the
same on all channels. Repeat step 13.
PAGE 4
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