Philips MCM720 Service Manual page 26

LAYOUT DIAGRAM - TUNER BOARD
1101 B5 1110 B4 1131 C5 2107 B3 2133 C1 2162 A4 5102 C4
1102 B5 1120 A4 1132 A4 2128 A3 2138 B1 2191 B4 5103 C4
1103 C5 1130 A5 2106 B4 2129 B3 2144 B1 3142 C2 5109 B3
TUNER BOARD ECO6 Systems - Cenelec /
Birdy Filter
11 - 2
5110 A2 5114 A2 5121 B2 7104 C4 9101 A2 9104 B1 9107 B4 9110 A4
5111 A3 5115 C2 5122 C3 7105 C5 9102 B2 9105 B1 9108 B3 9111 A3
5112 A2 5119 B2 5123 C3 7112 B1 9103 A1 9106 B1 9109 C2
componentside view
FM 75
AM FRAME AERIAL
ECO6 Sys-Cenelec, layout stage .8, 200803
TUNER ADJUSTMENT TABLE
Waverange Input frequency
VARICAP ALIGNMENT
FM
87.5 - 108MHz
A
(50kHz grid)
MW
531 - 1602kHz
(9kHz grid)
LW
153 - 279kHz
(3kHz grid)
FM - IF
10.7MHz, 45mV
FM
continuous wave
FM - VCO
B
98MHz, 1mV
FM
continuous wave
Note: The FM-frontend unit has already been adjusted by the factory
FM RF (channel separation)
98MHz, 1mV
FM 90% Left + 9% pilot
mod=1kHz
AM IF
450kHz
MW
connect pin 6 of
IC 7101 (AM Osc.)
with 3.3k to Vcc
AM AFC
MW
3)
AM RF
1 4 9 4 k H z
MW
558kHz
LW 1 9 8 k H z
Use Service Testprogram. By selecting the TUNER TEST test frequencies will be stored as preset frequencies automatically.
1)
If sensitivity of frequency counter is too low adjust to max. channel separation
(input signal: stereo left 90% + 9%, adjust output on right channel to minimum)
2)
RC network serves for damping the IF-filter while adjusting the other one.
3)
For AM RF adjustments the original frame antenna has to be used!
MW has to be aligned before LW.
Repeat
11 - 2
( ECO6 Cenelec FM/MW - and FM/MW/LW - versions with AM-frame aerial )
Input Tuned to Adjust Output
108MHz check
87.5MHz check
1602kHz 5123
1
531kHz check
279kHz 5122
153kHz check
IC 7101
21
D 5119 2
shortcircuit
2141
to block AFC
A 3
98MHz 3142
and needs therefore no further adjustments for service purposes.
IF coil
inside
A 4
98MHz
FM frontend
1110
IC 7101
36
C
100nF
5111
f = 10kHz
5
V = 0.5mV
IC 7101
RF 40
(as low as
100nF
5112
possible)
see
remark 2)
C
5114 2
continuous wave
V = 2mV
RF
1494kHz 2 1 0 6
B
558kHz 5102
5
f = 30kHz
V as low as
198kHz 5 1 0 3
RF
possible
Scope/Voltmeter
8V 1.2V
1.6V 0.5V
8V 0.2V
3-band
6.9V 0.2V
2-band
1.1V 0.4V
8V 0.2V
1.1V 0.4V
0mV 3mV
1)
152kHz 1kHz
right channel min.
f
o
symmetric
0mV 2mV
f
o
symmetric
ECO6 Sys Cenelec, 190599