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Alignment Instructions - Motorola 7VT1 Service Manual

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ALIGNMENT INSTRUCTIONS
If complete receiver alignment Is to he performed, It can most conveniently be done In the order outlined.
If the picture tube is removed, it will be necessary to short pins 1 and 14 of the picture tube socket to complete the filament circuit.
Use an isolation transformer to protect the test equipment.
SOUND IF ALIGNMENT USING AM SIGNAL GENERATOR AND VTVM
Connect a 10KO isolating resistor in series with the common lead of the VTVM and B- .
DUMMY
ANTENNA
.01MFD
.01MFD
SIGNAL
GENERATOR
COUPLING
High side to pin 1 (Grid)
of 6AU6 (V6). Low side
toB-.
"
SIGNAL
GENERATOR
FREQUENCY
4. SMC
1
(Unmod. )
i
1
"
CHANNEL
Iny channel
mused
ocally
"
CONNECT
ADJUST
VTVM
ADJUST
DC Probe to Poinfcfo
A1.A2
Common to B-.
DC Probe to Point^^
A3
Common to B-.
REMARKS
Adjust for maximum deflection.
Adjust for zero reading. A positive and negative
reading will be obtained on either side of the correct
setting.
SOUND If ALIGNMENT USING FM SIGNAL GENERATOR AND OSCILLOSCOPE
Use frequency modulated signal with 60 ~ modulation and 450KC sweep. Use 120 ~ sawtooth voltage in scope for horizonlal detlecnon.
DUMMY
ANTENNA
. 01MFD
, 01MFD
SWEEP
GENERATOR
COUPLING
High side to pin 1 (Grid)
of 6AU6 (V6). Low side
to B-.
"
SWEEP
GENERATOR
FREQUENCY
4. SMC
(450KC
Sweep)
'
MARKER
GENERATOR
FREQUENCY
4. SMC
VIDEO
CHANNEL
Any
channel
unused
locally
CONNECT
SCOPE
Vert. Amp. to Point
«^ Low side to B-.
Vert. Amp. to Point
<3J> Low side to B-.
ADJUST
A1.A2
A3
REMARKS
Adjust for maximum amplitude and symmetry
as per Fig 1.
Adjust A3 so 4. SMC marker occurs at
center of crossover lines as per Fig 2.
SLIGHTLY retouch A2 for maximum ampli-
tude and straightness of crossover lines.
F ALIGNMENT
Connect the synchronized sweep voltage from the signal generator to the horizontal input of the oscilloscope for horizontal deflection.
Connect the negative lead of a 3 volt battery through lOKft to the junction of R20 and C24. Connect the positive lead to.B-.
Unsolder une end of the oscillator cathode choke (L7), to disable the local oscillator.
If a wide band scope is used, connect a 1000MMF capacitor across the vertical amp. input terminals.
Set contrast control to minimum.
DUMMY
ANTENNA
. 01MFD
.01MFD
.01MFD
.01MFD
DUMMY
ANTENNA
.01MFD
SWEEP
GENERATOR
COUPLING
High side to pin 1 (Grid)
of 6AU6 (V3). Low side
toB-.
"
"
SWEEP
GENERATOR
COUPLING
High side to ungrounded
tube shield floating over
converter tube (V2).
Low side to B~.
SWEEP
GENERATOR
FREQUENCY
24.6MC
(12MC
Sweep)
"
.
ii
L
SWEEP
GENERATOR
FREQUENCY
24.6MC
(12MC
Sweep)
MARKER
GENERATOR
FREQUENCY
22. 9MC
26. SMC
"
. "
t IF TRANSF
MARKER
GENERATOR
FREQUENCY
23. IMC
26. IMC
CHANNEL
Any
"
"
ORMER AL
CHANNEL
Any
CONNECT
SCOPE
Vert. Amp. to Point
<^> Low side to B-.
"
11
GNMENT
CONNECT
-
SCOPE
^^ Low side to B-.
ADJUST
A4
AS
A6
A4
REMARKS
Adjust A4 for peak response near 26MC.
Adjust A5 for peak response near 24. 6MC.
Adjust A6 to place 22. 9MC marker at 50%
response on the low frequency slope of the
response curve.
Adjust A4 to place 26. 3M.C marker at 50%
response on the high frequency slope of
the response curve. If necessary slightly
retouch A4 thru A7 to obtain proper response
as shown in Fig 3.
ADJUST
A7.A8
REMARKS
Turn cores of A7 and A8 fully counter clock-
wise {fully out). Bring both cores in
simultaneously until 23. IMC marker occurs
at 50% response on the low frequency slope
and 26. IMC marker occurs at 50% response
on the high frequency slope of response
curve as shown In Fig 4. If 2 peaks appear,
the dip between them should not exceed 10%.
Resolder the cathode choke (L7).
,
,
Set the fine tuning control to the mid-position of its range.
Connect the synchronized sweep voltage from the signal generator to the horizontal input of the oscilloscope for horizontal deflection.
DUMMY
ANTENNA
Direct
Direct
Direct
SWEEP
.
GENERATOR
COUPLING
High side to upper "A"
terminal. Low side to
"G" terminal.
SWEEP
GENERATOR
FREQUENCY
195MC
(12MC
Sweep)
177MC
(12MC SWP)
183MC
(IZMC'SWP)
189MC
(12MC SWP)
201MC
(12MC SWP)
207MC
(12MC SWP)
213MC
(12MC SWP)
85MC
(12MC SWP)
79MC
(12MC SWP)
69MC
(I2MC SWP)
63MC
(12MC SWP)
57MC
(12MC SWP)
MARKER
GENERATOR
FREQUENCY
193.25MC
197. 75MC
175. 25MC
179.75MC
181. 25MC
185. 75MC
187. 25MC
191. 75MC
199. 25MC
203. 75MC
205. 25MC
209. 7 SMC
211. 25 MC
215. 75MC
83.25MC
87.75MC
77.25MC
81. 75MC
67.25MC
71. 75MC
61. 25MC
65.75MC
55. 25MC
59.75MC
CHANNEL
10
7
8
9
11
12
13
6
5
4
3
2
CONNECT
SCOPE
Vert. Amp. to Point
^> Low side to B-.
ADJUST
A9
A 10
All
A12
A13
A14
REMARKS
Adjust for response curve similar to Pig. 7
with markers as shown.
Check all high band channels to see that
markers placement as shown in Fig 7
occurs within 22 1/2 degrees of the mid-
position of the fine tuning control range.
If may be necessary to expand or compress
the turns of L6 to bring channel 13 within
the proper range. If L6 is adjusted repeat
steps 8 and 9.
Expand or compress coil turns to place
markers as shown in Fig 7.
PAGE 6

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