Daewoo DR-C912B, Service Manual

Page: 35 / 132

33
ADJUSTMENT OF THE TAPE TRANSPORT SECTION
H. ADJUSTMENT OF THE WAVE FORM OF
DRUM ENTRANCE /EXIT (FIG. 5.8)
a. Connect the PT01 on the MAIN CIRCUIT BOARD with a PATH
ADJ.FIXTURE.
b. Play back an ALIGNMENT TAPE(DN-2 : MONOSCOPE signal)
c. Connect the S/W PULSE TEST PIN on the PATH ADJ. FIX-
TURE with a CHANNEL-1 SCOPE PROBE.
d. Connect the VIDEO OUT on the MAIN CIRCUIT BOARD with a
CHANNEL-2 SCOPE PROBE(1V/div).
e. Turn the VR CONTROL on the PATH ADJ.FIXTURE clockwise
or counterclockwise until the signal shape of ENVELOPE has
the constant thickness.(Fig.5.8)
f. Adjust the S/T GUIDE ROLLER if the thickness of the ENVE-
LOPE signal is not uniform.
I. REVIEW PLAY(FIG. 5.9)
a. Connect the PT01 on the MAIN CIRCUIT BOARD with a PATH
ADJ.FIXTURE.
b. Play back an ALIGNMENT TAPE(DN-2 : MONOSCOPE signal)
c. Connect the S/W PULSE TEST PIN on the PATH ADJ. FIX-
TURE with a CHANNEL-1 SCOPE PROBE.
d. Connect the VIDEO OUT on the MAIN CIRCUITBOARD with a
CHANNEL-2 SCOPE PROBE (1V/div).
e. Make the VR CONTROL on the PATH ADJ. FIXTURE to the
center to maximize the ENVELOPE signal.
f. Play back the REVIEW mode about 15 second and alter the
mode to PLAY MODE.
g. Check whether the ENVELOPE waveform restore to its original
form within 3 second when the REVIEW mode is changed to
PLAY mode.
h. If the requirement of g is not satisfied, Check the running sta-
tus of tape on the lower part of TGUIDE POST and adjust the
S/T GUIDE ROLLER precisely
.
J. CHECKING AUDIO OUTPUT WAVEFORM
(ADJUSTMENT OF AC HEAD TILT &
HEIGHT)
a. Connect the AUDIO output jack with an AUDIO LEVEL METER.
b. Playback an Alignment Tape (DN-1:Color Bar 1KHz Signal)
c. Check if the AUDIO output signal level is over -9~-3dBm.
d. If the requirement of c is not satisfied, readjust the AC HEAD
TILT and the HEIGHT until the AUDIO output is maximized.
(Fig. 5.2, 5.3)
FIg.5.8 Fine adjustment of the ENVELOPE at the DRUM
ENTRANCE/EXIT
S/W PULSE TEST PIN PATH ADJ. FIXTURE
ENVELOPE TEST PIN PATH ADJ.FIXTURE
Measurement Equipment OSILLOSCOPE
VR CONTROL
PATH ADJ.FIXTURE
S/T GUIDE ROLLER TAPE TRANSPORT SECTION
Test Point
Adjustment
FIg.5.9 Waveform change when the modealtered
(REVIEW
↔
PLAY)
AUDIO OUTPUT AUDIO OUTPUT JACK
AUDIO LEVEL METER
Test Point
Measurement Equipment
S/W PULSE TEST PIN PATH ADJ. FIXTURE
ENVELOPE TEST PIN PATH ADJ.FIXTURE
Measurement Equipment OSILLOSCOPE
VR CONTROL
PATH ADJ.FIXTURE
S/T GUIDE ROLLER TAPE TRANSPORT SECTION
Test Point
Adjustment