Pioneer AVIC-X940BT, Service Manual

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AVIC-X940BT/XNUC
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8. EACH SETTING AND ADJUSTMENT
8.1 DVD ADJUSTMENT
This product uses 5 V and 3.3 V as standard voltages.
The electrical potential that is the reference for signals, is not GND, but VREF (approximately 2.2 V) and VHALF
(approximately 1.65 V) .
During product adjustments, if the reference voltage is mistakenly taken as GND, and a grounding contact is made,
not only would it be impossible to measure the accurate electrical potential, but also the servo motor
would malfunction, resulting in the application of a strong impact on the pick up.
The following precautionary measures should be strictly adhered to, in order to avoid such problems.
The reference voltage and GND should not be confused when using the minus probe of a measurement device.
When an oscilloscope is being used special care should be taken to make sure that the reference voltage is not
connected to the probe of ch1 (on the minus side), while the probe of ch2 (on the minus side), is connected to GND.
Further, since the body frame of most measurement devices have the same electrical potential as the minus side of
the probe, the body frame of the measurement device should be set to floating ground.
If the reference voltage is connected to GND by mistake, turn the regulator OFF immediately, or turn the power OFF.
Remove the filters and wires used for measurements only after the regulator has been turned OFF.
After the power supply is turned on, regulator ON the following adjustment and measurement are promptly done.
Whenever the product is in the test mode, the software will not take any protective action. For this reason, special
care should be taken to make sure that no mechanical or electrical shock could be applied to the product when
taking measurements in the test mode.
Whenever the EJECT key is pressed to eject the disk, no other keys, other than the EJECT key, should be pressed
until the disk eject action has been completed.
Press the EJECT key only after the disk has stopped completely.
If the product hangs up turn the power OFF immediately.
Don't touch the volume for laser power adjustment other than the time of POWER adjustment.
(Laser diode may be damaged.)