Failure Judgement Of The Pickup Assy - Pioneer CDJ-900 Service Manual

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5.3 FAILURE JUDGEMENT OF THE PICKUP ASSY

LD power after passing through the objective lens [mW]
SPEC: 0.147 ± 0.02
Check method: Measure the LD power, using an optical power meter.
Failure judgment: A value out of the range of the specifications is judged as failure.
Actuator resistance value [ohms]
Specifications on the focus side: 3.4 ± 0.5
Specifications on the tracking side: 4.1 ± 0.6
Check method: Disconnect* the FFC connected to the CN7001 on the focus side then measure the resistance value
between FFC pins 23 and 24.
Disconnect* the FFC connected to the CN7001 on the tracking side then measure the resistance value
between FFC pins 21 and 22.
*Short-circuit the LD short-circuit pad.
Failure judgment: A value out of the range of the specifications is judged as failure.
LD current [mA]
SPEC: TYP70 MAX80
Check method: Measure the LD current at the probe pad on the SRV Assy, using a tester.
[Check procedure]
1. For details on how to emit light from the LD, see the description on Drive Operation in Service mode.
2. With the LD OFF, apply the probes of a tester to the reference probe pad. (V+5 and LDI, see Fig. 1.)
Note: Be careful not to apply the probes to the pads with LD ON. If you do so, the LD may be damaged.
3. With the probes applied to the above-mentioned pads, turn the LD ON to measure the voltage between them.
4. After measurement, turn the LD OFF (ALL OFF) then pull the probes away.
5. Divide the measured voltage value by 12 ohms (resistance value), and calculate current value.
Failure judgment: If the calculated current value exceeds the maximum value, the LD has been degraded
Fig. 1 SRV Assy
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6
V+5
LDI (Reference probe pad)
CDJ-900
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7
7
8
A
B
C
D
E
F
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