Troubleshooting - Kenwood DP-1100 B Service Manual

4-1 Checking flow chart of the start operation from the moment power is switched on until operation
is enabled. * Actual action taken by DP-1100B/II
Circuits a n d signal line w r i t t e n in parenthesis in the left c o l u m n is the place to be c h e c k e d .
( P O W E R oi\P)
The microprocessor
is reset.
1 r
The tray position is
detected.
* W h e n it is open, the tray is retract­
r
The pickup position
is detected.
* W h e n the pickup is at the outer
Laser diode goes on; focus search starts;
forward kick; the disc motor operates in­
stantaneously.
(LDC, focus search (FSRCH), PUFB, F G S ,
inverter buffer output MSP)
(kick motor circuit)
* W h e n
A b s e n c e or pre­
(Focus error, DOK)
sence of the disc is
(Focus servo)
detected.
* W h e n there is no disc, the laser diode
DISC motor start (IC15, MSP, A F C , CLV)
RFOK is detected.
(S1, S 2 , E F M , RFOK)
(Focus servo, A G C )
(Slice level)
Focus servo on
(FOK)
Focus search stop
* T max. is detected.
(Focus servo)
Tracking servo on
(FOKG, K G C , T E : Tracking error)
(Tracking servo) (Dropout control)

4. TROUBLESHOOTING

(reset circuit)
(limit switch): S L T
(close or open): C L S , OPEN
ed and proceed to the next opera­
tion.
(limit switch)
(SLT)
(P.U. motor circuit)
tracks of the disc, it moves to the
innermost tracking position and
proceed to the next operation.
there is no disc, the motor
rotates in the forward direction momen­
tarily (clockwise), then in reverse (ap­
prox. 2 s e c ) .
goes out, then focus search stops and
fluorescent indication " D I S C " goes
out.
POWER ON-
FL display
T R A C K
Flashes-
• ( . D I S C )
1
Pull out the tray, then switch on the power without
inserting the disc.
1
The tray is retracted.
1
The pickup moves slightly backwards, and the laser diode is
reflected in pale red on the pickup lens.
The pickup moves 1 mm or so vertically.
The disc motor momentarily rotates in the forward direction, then
reverses for about 2 sec. before stopping. The fluorescent display
DISC goes out.
Pull out the tray, then insert the disc.
The tray is closed.
1
The disc rotates momentarily, then resumes normal revolution.
(If it does not rotate, check DOK, and A F C . )
With the sound of the rotating disk, the EFM presents jitterless
waveform. (FOCUS, tracking servo on)
* If there is no sound and the E F M , RFOK, or EFM waveform is jit­
tered, check-the tracking circuit.
D P - 1 1 0 0 B II
Rising edge of 5 V power
Reset
N O .
T I M E
131