Akai AT 2650 Service Manual

Page 20

1,FM TUNER SECTION ADJUSTMENT (Refer to Figs. 23, 24)

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Step Adjustment ltem Adjustment Point Result Remarks
M 'mu SELECTOR to PM MONO. FM
1 Front End 1F Coil 23;; em MUTE and NOISE CANCEL to
IF Coil (Front End) 3 OFF, Tune only noise without
Level . ,
interference of broadcasting.
. Centered
2 Tucnmg Meter T5 (WHT) Tuning Meter Same as above.
entering (Tuner P.C Board) , _
Indication
Distortion T6 (BLU) Less-than-�0.1% 98 MHz, 60 dB (mono) input,
3 Factor (Tuner P C Board) Distortion Less than 0.1% on both channels
' Factor See NOTE 1.
Confirmation If Tuning Meter Indication is not
of Tuning .
4 centered re-adjust Step 2 and
Meter 3 above
Indication '
High Range M x' mm 108 MHz, 60 dB (mono) input.
5 Scale TCo (Front End) 3 1!-� m TUNING INDICATOR to 108
Indication -� 9 MHz. Error: Within :250 kHz.
Effigxnfigf; M x'mum 88 MHz, 60 dB (mono) input.
6 s W D O -�1 m TUNING INDICATOR to as
.° . -� P MI-Iz. Error: thIn :250 kHz.
Indication
04
High Range TCA, TCRI, TCRZ, TCR3 Les? -�1-�-�? 3/-� 108 MHz, Less than 4 dB(mono)
7 Sensitivity (Front End) Distortion input
Factor -�
8 Low Range LRI, LR2, LR3 -�SitthftIE? 98 MHz, Less than 3 dB(mono)
Sensitivity (Front End) 1 O 1 input. See NOTE 2.
l Factor
Confirmation Less than 3% 98 MHZ, Less than 4 dB(inonc)
9 of Mid Range Distortion ,
. . . input. See NOTE 2.
SenSItiVIty Factor
PLL Free FM SELECTOR to FM AUTO.
. VR6 5 kB FM MUTE to ON. Connect
10 Running 1900 kHz .
Fre uenc (Tuner BC Board) frequency counter to Test Pom;
q V See NOTE 3.
Confirmation 98 MHZ. 60 dB (stereo) inpur.
of Stereo , . . .
11 , Unlet stereo Indicator indicans
Indicator 0 ter 0 tion
Lighting n s e separa .
Stereo VRl 20 kB More than FM MUTE to OFF. 98 MHz,
12 Separation (Tuner P C Board) 45 dB 60 dB (stereo), Lch input
(LeftnRight) ' Minimum output of R ch.
13 562:3)-� VRl 20 kB More than 98 MHz, 60 dB (stereo), Rm
(Right-deft) (Tuner RC Board) 45 dB Input Minimum output of L Ch
-� sr I '
. gna Meter VR4 50 kB Indicator .
14 l Sensitivity (Tuner P,C Board) at -�4.5-� 98 MHZ-� 100 dB (mono) input (-1
Curr H
NOTES: 1. When the distortion factor is not less than 0.1% in Step 3 adjust by turning the Front End IF C Oil

core but not more than 1/2 turn.
2. In the event that distortion factor in Step 9 is not less than 3%, re~adjust step 7 & 8 obtan 3%
distortion factor.
3. PLL IC free running frequency must be an exact 1900 kHz.

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