Panasonic KX-P7100 Service Manual page 60

KX-P7100
4.4.9. Laser Scanning Unit Control Circuit
The laser unit consists of laser drive circuit and scanner motor drive circuit.
Laser control signals are as follows.
nVIDEO:
nLDON:
nHSYNC:
nADJUST:
nSNRCTL:
nSNRLD:
nSNRCLK:
This is actual data being printed.
When the nLDON signal is low, the laser unit is activated.
When front door is opened, the laser unit is deactivated.
This is a horizontal synchronizing signal sent from a timing sensor ( laser beam detect sensor )
which detects horizontal position of the laser beam across drum.
When the nADJUST signal is low, APC ( Auto Power Control ) is activated.
This is a control signal for the scanner motor.
The scanner motor speed is maintained at approx. 20K rpm by a PLL ( Phase Locked Loop ).
While the scanner motor rotates ( approx. 20K rpm ), nSNRLD is low.
This is a reference clock of the scanner motor ( approx. 2KHz ).
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