JVC RC-XC3BK

RC — XC3BK B/E/EN/G/GI |
7. Troubleshooting
mg Pickup maintenance
(1) Checking the service life of laser diode
If a laser diode reaches the end of its service life, the following phenomena will show up. Similar symptoms may
aiso appear when the pickuplens becomes too dirty. In this case, clean the lens.
1) The RF output (between IC601 @ and @ (GND)) lowers.
2) The driving current, necessary for the laser diode to emit lights, increases. (Calculate from the voltage level at
both ends of the R614 at 10 Q .)
Following the flow chart shown below, check the service life.
Clean pickup lens
Is RF output at 0.45 V p-p or more? Any dirt or scratches on disc? Replace pickup
Is laser diode's driving current at less than
100 mA?
Replace pickup
How to measure laser diode’s driving current
After connecting a voltmeter at both ends of the R614(10 2 ), measure the voitage during playback. If the voltage
level is at 1.0 V or more, the service life of the laser diode has expired.
Laser diode’s driving current (A)
= Voltage level at both ends of R614 (V)/10 (Q )
When voltage level is at 1.0 V:
1.0VA0Q2 =0.1A=100mA
Note:
The laser diode easily breaks down. Be sure to turn the power off before connecting a voltmeter.
46 (No. 1991)