PIONEER DEH-546
Manual de Servicio

DEH-P646,546

6.2 CD SECTION
1)Precautions � This unit uses a single power supply (+5V) for the regulator. The signal reference potential, therefore, is connected to REFO(approx. 2.5V) instead of GND. If REFO and GND are connected to each other by mistake during adjustments, not only will it be impossible 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 following. Do not connect the negative probe of the measuring equipment to REFO and GND together. It is especially important not to connect the channel 1 negative probe of the oscilloscope to REFO with the channel 2 negative probe connected to GND. Since the frame of the measuring instrument is usually at the same potential as the negative probe, change the frame of the measuring instrument to floating status. If by accident REFO comes in contact with GND, immediately switch the regulator or power OFF. � Always make sure the regulator is OFF when connecting and disconnecting the various filters and wiring required for measurements. � Before proceeding to further adjustments and measurements after switching regulator ON, let the player run for about one minute to allow the circuits to stabilize. � 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 system when making adjustment. � Test mode starting procedure Switch ACC, back-up ON while pressing the 4 and 6 keys together. � Test mode cancellation Switch ACC, back-up OFF. � Disc detection during loading and eject operations is performed by means of a photo transistor in this unit.Consequently, if the inside of the unit is exposed to a strong light source when the outer casing is removed for repairs or adjustment, the following malfunctions may occur. *During PLAY, even if the eject button is pressed,the disc will not be ejected and the unit will remain in the PLAY mode. *The unit will not load a disc. When the unit malfunctions this way, either re-position the light source, move the unit or cover the photo transistor. � When loading and unloading discs during adjustment procedures, always wait for the disc to be properly clamped or ejected before pressing another key. Otherwise, there is a risk of the actuator being destroyed. � Turn power off when pressing the button � or the button � key for focus search in the test mode. (Or else lens may stick and the actuator may be damaged.) � SINGLE/4TRK/10TRK/32TRK will continue to operate even after the key is released.Tracking is closed the moment C-MOVE is released. � JUMP MODE resets to SINGLE as soon as power is switched OFF.

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