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3-14

Only for training and service purposes.

ONE POINT REPAIR GUIDE

6. NO SOUND

There is no sound output by DIGITAL AUDIO AMP DAMAGE, repair the set according to the

following guide.

6-1. DIGITAL AUDIO AMP DAMAGE

6-1-1. Solution

Replace IC701, IC702 on MAIN board.

6-1-2. How to troubleshoot (Countermeasure)

1) Check PWM_FL±, PWM_FR± & PWM_SW± signals from IC601 to IC701 & 702 each input function.

 If no signal, check if I2S audio signals are entered to IC601.

2) Check PVDD.

 If PVDD is abnormal, check the SMPS.

3) Check AMP_12V for driving the gate of AMP IC.

a. All the powers are normal, but if AMP_12V is low, there is possible for AMP IC to be damaged.

b. Remove L705, L706, L707 and L708 one by one.

When removed a inductance, if AMP_12V is recovered, the IC connected to it was damaged.

c. Replace the IC with a new one.

4) Check the impedance between IC701/IC702_OUT_A/OUT_B & GND.

a. If the impedance is 0 Ω, the IC must be damaged.

b. After removing the heat sink, replace it with a new one.

6-1-3. Service hint (Any picture/ Remark)

< MAIN board top view >

IC701

L708

L707

L705

L706

IC702

IC601

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