Fisher TAC-M82 Service Manual page 3

AM TUNER ALIGNMENT
AM ALIGNMENT — FUNCTION switch to MW or LW position.
Maintain generator output as low as possible for suitable indication.
ITEM GENERATOR DIAL SETTING
Note: Perform this alignment after FM Tuner Alignment.
INDICATOR PROCEDURE
1. AMIF Connect 450kHz Radio Position of Connect Radio IF Adjust AM IFT (T7105) for maximum
ALIGNMENT IF Genescope output non-interference Genescope input gain and best symmetry.
to Pin W1 and W2 Adjust | Minimum to TP6 and ground | Keep signal low enough for noise
lead to chassis.
Connect DC Volt-
output level to 70dByV.
Do not connect
Frequency. on response.
FREQUENCY generator. DIGITAL Counter meter to TP2 and | 7.0V ~ 9.0V.
COVER Display ground jead to
ALIGNMENT Set to 1611kHz. chassis.
(161 1kHz)
3. Same as above.
(522kHz)
Check DC Voltmeter for Indication
1.0V ~ 1.4V.
DIGITAL Counter Same as above.
Display
Set to 522kHz.
Note: Repeat the adjustments in items 2 and 3. Then, confirm that each voltage becomes 1.3V to 8.03V at receiving frequency
of 522kHz to 1611kHz. (See Table 1)
4. LW RF Do not connect Front Panel Connect DC Volt-
Check DC Voltmeter for Indication
FREQUENCY generator. DIGITAL Counter meter to TP2 and 6.0V ~ 8.0V.
COVER Dispiay ground lead to
ALIGNMENT Set to 360kHz. chassis.
(360kHz)
5. Same as above.
(153kHz)
Check DC Voltmeter for Indication
0.7V ~ 1.2V.
Same as above.
DIGITAL Counter
Display
Set to 153kHz.
6. MW RF Connect Standard Loop
TRACKING Antenna to output
ALIGNMENT terminal of AM RF Signal
(603kHz) Generator. Place Loop
Antenna 60cm away from
Loop antenna (Unit).
Generator Setting to
603kHz or 1404kHz.
Modulate with 400Hz to "2" position.
(30 % modulation). Set to 1404kHz.
Note: Repeat the adjustments in Items 6 and 7. Then, confirm there is no tracking error.
(160kHz)
Connect AC VTVM } Adjust MW ANT Coil (T101) for
and Oscilloscope maximum gain output.
to SPEAKER OUT.
Set Preset
STATION button
to "1" position.
Set to 603kHz.
Adjust MW ANT Trimmer (TC101)
for maximum gain output.
Change Preset Same as above.
STATION button
(1404kHz)
Set Preset
STATION button
to "4" position.
Set to 160kHz.
Change Preset
STATION button
to "5" position.
Set to 350kHz.
Note: Repeat the adjustments in Items 8 and 9. Then, confirm there is no tracking error.
10. AM AUTO
STOP
SENSITIVITY
ADJUSTMENT
Change generator
setting to 160kHz.
Adjust LW ANT Trimmer (TC102)
for maximum gain output.
Change generator Same as above.
setting to 350kHz.
(350kHz)
Front Panel
TUNED Indicator
Display.
Adjust P102 until the !ndicator
partly light up.
Set Preset
STATION button
to "3" position.
Set to 999kHz.
Change generator
setting to 999kHz and
output level to
60dBuV/m.
Use a screwdriver with plastic grip for all adjustments.