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ELECTRICAL TROUBLESHOOTING GUIDE
3. POWER SUPPLY ON MAIN BOARD
No 3.3 V.
Check IC151 and replace.
Is the VCC 3.8 VA supplied to IC151 pin3?
Is there ‘H’ signal at IC153 pin2?
Check 3.8 VA on SMPS Board.
Check IC101 pin58 (DCDC33_CTRL).
NO
NO
YES
YES
YES
No 5 V.
Check IC153 and Replace.
Is the VCC 6 VA supplied to IC153 pin2?
Is there ‘H’ signal at IC153 pin1?
Check 6 VA on SMPS Board.
Check IC101 pin68 (LDO_CTRL).
NO
NO
YES
YES
YES
No 1.2 V.
Check IC155 and replace.
Is the VCC 14 VA supplied to IC155 pin2?
Is there 1.2V at IC155 pin8?
Check 14 VA on SMPS Board.
Check IC101 pin68 (LDO_CTRL).
NO
NO
YES
YES
YES
No 1.5 V.
Check IC150 and replace.
Is the VCC 14 VA supplied to IC150 pin13?
Is there 1.5 V at IC150 pin12?
Check 14 VA on SMPS Board
Check IC101 pin59 (DCDC15_CTRL).
NO
NO
YES
YES
YES
Summary of Contents for BH4120SN
Page 56: ...2 47 WAVEFORMS IC501 MT8560 X TAL 27 MHz 1 1 7 8 10 9 1 SYSTEM PART 1 ...
Page 59: ...2 50 WAVEFORMS H_SDA H_SCL 11 12 5 HDMI PART 12 11 ...
Page 60: ...2 51 WAVEFORMS HDMI_CLK_N 13 13 12 11 14 HDMI_0_N 14 JK803 ...
Page 61: ...2 52 ...
Page 79: ...2 87 2 88 2 MAIN P C BOARD TOP VIEW BOTTOM VIEW ...
Page 80: ...3 AMP P C BOARD TOP VIEW BOTTOM VIEW 2 89 2 90 ...
Page 81: ...4 JACK P C BOARD 5 FRONT P C BOARD TOP VIEW BOTTOM VIEW 2 91 2 92 TOP VIEW BOTTOM VIEW ...
Page 83: ...3 2 ...
Page 87: ...A800 Front SPK A700 Center SPK A600 Rear SPK 4 SPEAKER SECTION 4 1 FRONT CENTER REAR SPEAKER ...
Page 88: ...A900 4 2 PASSIVE SUBWOOFER ...
Page 89: ......
Page 103: ...4 14 MEMO ...