Philips MC-M250 Service Manual page 24

TAPE ADJUSTMENT & CHECK TABLE
TEST
RECORDER
CASSETTE
MODE
SBC420
MOTOR SPEED PLAY
3150Hz
SBC420
WOW & FLUTTER
PLAY
3150Hz
PLAY FWD
SBC420
ADJUST AZIMUTH
10kHz
PLAY REV ^
SBC420
PLAYBACK LEVEL
PLAY
& FREQ. RESPONSE 315Hz
CHECK RECORD/PLAYBACK FREQUENCY AND DISTORTION
Inject 3mV signals
SBC419A
100Hz, 250Hz, 1kHz,
10kHz, 12.5kHz or RECORD
SBC420
via or
3 4
RECORDED
PLAY
CASSETTE
Inject 1kHz 8.85mV
SBC419A
or
RECORD
via or 4
3
SBC420
RECORDED
PLAY
CASSETTE
SBC419A : 4822 397 30069
SBC420 : 4822 397 30071
level(dB)
8dB 6dB 8dB
80 250 4k 12.5k
figure. 1
10 - 3
ADJUST
MEASURE
READ ON
ON
with
frequency
check
counter
check
W&F-meter
or
1 2
left hand screw
LEFT RIGHT
mV-meter
right hand screw
mV-meter
check
1 or 2
mV-meter
check
LEFT RIGHT
or
1 2
THD-meter check
LEFT RIGHT
^ 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
level(dB)
8dB 6dB
f(Hz)
100 250 4k
figure. 2
EXPLODED VIEW - TAPE MODULE
to
3150Hz +/- 2%
< 0.4 % DIN
max. output level
& left=right
125mV +/- 3dB
(see fig.1 for freq.
response)
1002
limits see fig. 2 *
< 3% *
8dB
f(Hz)
10k
10 - 3
1001
1000
3
2
1
3139 118 78730_Module Tape Deck ETF8 SD dd wk0125