HP WF1907 Service Manual page 7

The P309 is audio signal input from the audio source.
3.7.2 P310 connector
The P310 is audio output to speaker and support 2W x 2 speakers.
3.7.3 I310 TPA6021A4
The I310 is 2x2W stereo audio amplifier, it is an integrated class-AB dual output amplifier.
3.7.4 Q309 : Power down and mute control for Audio
ON/OFF control (AUDIO_EN) is performed for standby mode and mute function. It is
support 5V to audio IC power. The AUDIO_EN signal is generated from I306 scaler
Gm5726H (Gm5766H).
3.7.5 R394, Q310: Volume control for Audio
Volume control (volume) is performed for audio output signal power. The volume signal is
generated from I306 scaler Gm5726H (Gm5766H).
3.8 Others
3.8.1 Detection of POWER ON status
The I306 Gm5726H (Gm5766H) identified the ON status of two modes for the power
supplies. The identification is made when the power supply is turn off. For example, if the
power supply is turn off with the POWER key switch, the POWER key switch must be turn
on when active the power supply again. If the power supply turned off by the pulling out the
power cord, then this power supply can to be turned on by connecting the power cord,
without pressing the POWER key switch.
3.8.2 Display mode identification
3.8.2.1 Display mode identification
The display mode of input signal is identified based on Table 2.
When the mode has been identified through the measurement of horizontal
and vertical frequencies, the total number of lines is determined with a formula of
"Horizontal frequency / Vertical frequency = Total number of number of lines".
Final identification can be made by examining the coincidence of the obtained
figure with the number of lines for the mode identified from the frequency. The
Distinction Hsync and Vsync of each mode is shown in Table 3.
When the detected frequency if the sync signal has changed, the total number
of lines should be counted even through it is range identified frequency in the
same mode.
3.8.2.2 Out of range
This out of range mode is assumed when the frequency out of the horizontal /
vertical signal is as specified below.
Vertical frequency : 50 ~ 76 Hz.
Horizontal frequency : 24 ~ 83KHz.
3.8.2.3 Power save mode
The power save mode is assumed when the horizontal / vertical signals are as
specified below.
If there is no horizontal sync signal input.
If there is no vertical sync signal input.
If the horizontal sync signal is outside the measuring range of I306 Gm5726H
(Gm5766H).
If the vertical sync signal is outside the measuring range of I306 Gm5726H
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