Pioneer DEH-P840MP Service Manual page 57

6.3 CD ADJUSTMENT
1) Precautions
• This unit uses a single power supply (+3.3V) for the
regulator. The signal reference potential, therefore, is
connected to REFO1(approx. 1.65V) instead of GND.
If REFO1 and GND are connected to each other by
mistake during adjustments, not only will it be impos-
sible to measure the potential correctly, but the servo
will malfunction and a severe shock will be applied to
the pick-up. To avoid this, take special note of the fol-
lowing.
Do not connect the negative probe of the measuring
equipment to REFO1 and GND together. It is especial-
ly important not to connect the channel 1 negative
probe of the oscilloscope to REFO1 with the channel 2
negative probe connected to GND.
Since the frame of the measuring instrument is usual-
ly at the same potential as the negative probe, change
the frame of the measuring instrument to floating sta-
tus.
If by accident REFO1 comes in contact with GND,
immediately switch the regulator or power OFF.
• Always make sure the regulator is OFF when connect-
ing and disconnecting the various filters and wiring
required for measurements.
• Before proceeding to further adjustments and mea-
surements after switching regulator ON, let the player
run for about one minute to allow the circuits to stabi-
lize.
• Since the protective systems in the unit's software are
rendered inoperative in test mode, be very careful to
avoid mechanical and /or electrical shocks to the sys-
tem when making adjustment.
• The RFI and RFO signals are easy to oscillate because
of a wide band. When observing them, insert a resis-
tor of about 1 kΩ to the series.
• This equipment will not guarantee the load ejection
operation when the mechanical unit is turned upside
down. In particular, if the ejection operation is incor-
rectly performed and recovery is disabled, the recov-
ery is enabled by resetting a product or turning ACC
off to on.
DEH-P840MP,P8400MP,P8450MP
2) Test Mode
This mode is used for adjusting the CD mechanism
module of the device.
• Test mode starting procedure
Reset while pressing the 4 and 6 keys together.
• Test mode cancellation
Switch ACC, back-up OFF.
• After pressing the EJECT key, do not press any other
key until the disk is completely ejected.
• If the ] or [ key is pressed while focus search is in
progress, immediately turn the power off (otherwise
the actuator may be damaged due to adhesion of the
lenses).
• Jump operation of TRs other than 100TR continues
after releasing the key. CRG move and 100TR jump
operations are brought into the "Tracking close" sta-
tus when the key is released.
• Powering Off/On resets the jump mode to "Single
TR(91)", the RF AMP gain setting to 0 dB, and the
automatic adjustment value to the initial value.
57