Moto X Pure Edition/Moto X Style
Baseband TROUBLESHOOTING GUIDES
MOTOROLA CONFIDENTIAL
Top Earpiece and Speaker Circuit
- Inspect the physical placement of U6404 and its related components on main
PCB. (See schematic in the previous slides)
- Verify that B_PLUS voltage is present on the LS_BOOST node, the junction of
C6421 and C6424.
- Connect an 8
Ω
speaker to the contacts on M4670 with short, thick wires. While
playing audio at normal to high volume, use an oscilloscope to verify that the
voltage on the VBST_LEFT_AMP node, the junction of C6423 and C6425,
alternates between B_PLUS voltage and approximately 9 V, depending on the
audio content.
- While playing media audio at normal to high volume, probe the voltage across
C6422. A 384 kHz PWM waveform should be observed, similar to the example
shown below. The waveform amplitude should vary between 2 x B_PLUS up to 18
V p-p depending on the audio content.
