PIONEER DEH-340
Manual de Servicio

DEH-340,3400,34

6. ADJUSTMENT
6.1 CD ADJUSTMENT
1) Precautions � This unit uses a single power supply (+5V) for the regulator. The signal reference potential, therefore, is connected to VREF(approx. 2.1V) instead of GND. If VREF 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 VREF and GND together. It is especially important not to connect the channel 1 negative probe of the oscilloscope to VREF 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 VREF 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. � The RFI and RFO signals are easy to oscillate because of a wide band. When observing them, insert a resistor of about 1 k� 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 incorrectly performed and recovery is disabled, the recovery is enabled by resetting a product or turning ACC off to on. 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).

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