Panasonic SA-XH50P, Service Manual

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8.2. DVD/CD Laser Diode current measurement.
This section will illustrate proceddures of measuring& deriving DVD/CD Laser Diode Current.
DVD Laser Diode Current Measurement
CD Laser Diode Current Measurement
Checking Item/ Formula Remarks Item Description
1. Measurement the voltage (V
CD
) on the testpoints ) & CL8531(-).
This is voltage across R8566 which has a resistance value of 4.7 ohm.
2. Calculate the CD Laser current by the following formula:
CD_LD=VCD/4.7
1. Measurement the voltage (V
DVD
) on the testpoints ) & CL8532(-).
This is voltage across R8556 which has a resistance value of 4.7 ohm.
2. Calculate the DVD Laser current by the following formula:
DVD_LD=VCD/4.7
Refer to 8.2.1.
Backend P.C.B.
(Fig. 3. Backend
P.C.B.)
Refer to 8.2.1.
Backend P.C.B.
(Fig. 3. Backend
P.C.B.)
3. Specification for CD laser current is 58 mA
3. Specification for DVD laser current is 58 mA