Wednesday, February 21, 2018

Sony HCD GPX5G – 4-ch D-Amp circuit diagram, how to take disc out in emergency

Sony HCD-GPX5G/GPX7G/GPX8G
Precaution when installing a new op unit/ precaution before unsoldering the static electricity prevention solder bridge
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.
When installing a new OP unit, be sure to connect the flexible printed circuit board first of all before removing the static electricity prevention solder bridge by unsoldering. 
Remove the static electricity prevention solder bridge by unsoldering after the flexible printed circuit board has already been connected.
(Do not remove nor unsolder the solder bridge as long as the OP unit is kept standalone.)
The laser beam on this model is concentrated so as to be focused on the disc reflective surface by the objective lens in the optical pickup block. Therefore, when checking the laser diode emission, observe from more than 30 cm away from the objective lens.
Releasing the disc tray lock
The disc tray lock function for the antitheft of an demonstration disc in the store is equipped.
1. Press 1 STANDBY] button to turn the power on.
2. Press the [CD/DISC SKIP] button to select CD function.
3. While pressing the [Stop] button, press the [ENTER] button for more 5 seconds).
4. The message “UNLOCKED” is displayed and the disc tray is unlocked.
Note: When “LOCKED” is displayed, the slot lock is not released by turning power on/off with the [ STANDBY] button.

How to open the tray when power switch turn off or there is no power [Emergency]
4 channel D-Amp board – schematic
PWB -  Component and foil side