Zenith J584W - Page 17

RF, IF, AND MPX ALIGNMENT PROCEDURE FOR CHASSIS 15WJR29 - CONT'D.
<
STEP
CONNECT
GENERATOR
TO
DUMMY (
ANTENNA
CONNECT
VTVM/
SCOPE TO
INPUT
SIGNAL
FREQ.
SET DIAL
TO
ADJUST
PURPOSE
NOTE:
Apply Sufficient Signal Level — Approx. 100 Microvolts — To Obtain Full Limiting
At Point Near 98 MHz.
24
Test Point "A"
FM Antenna Post
Disconnect Antenna)
300 Ohm
Scope
Test Point
"H"
98 MHz
98 MHz '
Turn Modulation "ON". Adjust
generator RF frequency to obtain
center indication on Tuning Meter.
Adjust VTVM for "O" dB reading.
25
Turn modulation "OFF". Reduce
RF level to get — 45 dB quieting
(approx. 3 to 4 microvolts).
26
R308 Turn Mute "ON". Rotate R308
(Mute) full clockwise. Audio will
mute. Slowly adjust R308 counter 
clockwise until audio just turns "ON".
Do not over adjust. This will be
approximately 45 dB S/N. To check,
tune generator off frequency and
then back on frequency from both
sides.
27
Frequency
Counter and/
_ or Scope _
Test Point
"M"
No Signal
Input.
Mute "ON".
R317
A. Frequency Counter should read
19 KHz. + 100 Hz.
B. Alternate Method: Connect Test
Point "M" Signal to scope vertical and
an accurate 19 KHz signal to scope
horizontal input. Adjust R317 for one
square synchronized waveform.
28
Scope and/or
AC VTM
Left Tape
Output
98 MHz
10% Pilot
- (L+'R) (L-R)
(L Only)
Check for separation. Maximum
left output.
29
Right Tape
Output.
Check for separation. Minimum
right output.
NOTE: Do Not Readjust Control R317 After Step 27.
CERAMIC FILTERS - CHASSIS 12WJR29
NOTE: BOTH CERAMIC FILTERS IN A GIVEN CHASSIS MUST BE
THE SAME PART NUMBER AND COLOR CODE.
PART NO.
COLOR CODE
NOMINAL CENTER
FREQUENCY
FREQUENCY
RANGE
224-1
Black
10.64 MHz 10.61 to 10.67 MHz
224-1-01
Blue
10.67 MHz
10.64 to 10.70 MHz
224-1-02
Red 10.70 MHz
10.67 to 10.73 MHz
224-1-03 Orange 10.73 MHz
10.70 to 10.76 MHz
224-1-04 White 10.76 MHz
1«.?S to 18.18««;
FIGURE 4 - CERAMIC FIL TER TABLE
15