Sony MZ-R900 Service Manual - Page 3

SECTION 1 SERVICING NOTES MZ-R900 NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK OR BASE UNIT The laser diode in the optical pick-up block may suffer electrostatic break-down because of the potential difference generated by the charged electrostatic load, etc. on clothing and the human body. During repair, pay attention to electrostatic break-down and also use the procedure in the printed matter which is included in the repair parts. The flexible board is easily damaged and should be handled with care. • In performing the repair with the power supplied to the set, removing the MAIN board causes the set to be disabled. In such a case, fix a convex part of the open/close detect switch (S806 on MAIN board) with a tape in advance. Handle the FLEXIBLE board (overwrite head) with care, as it has been soldered directly to the MAIN board. In repairing the component side of MAIN board, connect the FLEXIBLE board (overwrite head) and the MAIN board with the lead wires in advance. (See page 7) NOTES ON LASER DIODE EMISSION CHECK Never look into the laser diode emission from right above when checking it for adjustment. It is feared that you will lose your sight. NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK (LCX-4R) The laser diode in the optical pick-up block may suffer electrostatic break-down easily. When handling it, perform soldering bridge to the laser-tap on the flexible board. Also perform measures against electrostatic break-down sufficiently before the operation. The flexible board is easily damaged and should be handled with care. FLEXIBLE board (Over write head) Tape S806 upper panel assy MAIN board laser-tap OPTICAL PICK-UP FLEXIBLE BOARD • Replacement of CDX2671-203GA (IC801) used in this set requires a special tool. • On the set having the microcomputer version 1.000, some adjusted values were set in the manual mode at the shipment, but these data will be cleared when the NV is reset. Therefore, on the set having the microcomputer version 1.000, change the adjusted values following the Change of Adjusted Values immediately after the NV was reset. (See page 17) • If the nonvolatile memory was replaced on the set, the modified program data must be written to the nonvolatile memory. In such a case, write the modified data that meets the microcomputer version following the patch data rewriting procedure at the replacement of nonvolatile memory. (See page 22) CAUTION Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure. Notes on chip component replacement • Never reuse a disconnected chip component. • Notice that the minus side of a tantalum capacitor may be dam- aged by heat. Flexible Circuit Board Repairing • Keep the temperature of the soldering iron around 270 ˚C dur- ing repairing. • Do not touch the soldering iron on the same conductor of the circuit board (within 3 times). • Be careful not to apply force on the conductor when soldering or unsoldering. 3