Philips MCM390, Service Manual

Page: 24 / 38

9 - 3 9 - 3
TAPE ADJUSTMENT & CHECK TABLE
^ For Auto-reverse version only
* If high frequencies are not within limits, decrease bias and re-measure.
If distortion is too high, increase bias and re-meaure
PLAY
mV-meter
check
125mV +/- 3dB
(see fig.1 for freq.
response)
PLAYBACK LEVEL
& FREQ. RESPONSE
TEST
CASSETTE
RECORDER
MODE
MEASURE
ON
READ ON
ADJUST
with
MOTOR SPEED
SBC420
3150Hz
PLAY
frequency
counter
check
PLAY
PLAY FWD
PLAY REV ^
W&F-meter
mV-meter
left hand screw
right hand screw
max. output level
& left=right
WOW & FLUTTER
ADJUST AZIMUTH
/- 2%
< 0.4 % DIN
to
1 2
or
LEFT RIGHT
Inject 3mV signals
100Hz, 250Hz, 1kHz,
10kHz, 12.5kHz
1 2
or
LEFT RIGHT
Inject 1kHz 8.85mV
3 4
or via
3 4
or via
1 2
or
LEFT RIGHT
RECORD
RECORD
PLAY
PLAY
mV-meter
THD-meter
check
check
limits see fig. 2 *
< 3% *
RECORDED
CASSETTE
RECORDED
CASSETTE
figure. 1
f(Hz)
level(dB)
8dB
6dB
12.5k 4k
250 80
8dB
f(Hz)
level(dB)
8dB
6dB
10k 4k
250 100
8dB
figure. 2
check
SBC419A : 4822 397 30069
SBC420 : 4822 397 30071
SBC420
3150Hz
SBC420
10kHz
SBC419A
or
SBC420
SBC419A
or
SBC420
SBC420
315Hz
CHECK RECORD/PLAYBACK FREQUENCY AND DISTORTION
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