12-12-2014, 09:45 PM
(12-12-2014, 07:25 PM)Old Sparky Wrote:(12-12-2014, 01:04 PM)Mark Hennessy Wrote: Different laser for CDs - different wavelengths... It's entirely possible that the CD laser has a problem but the DVD laser remains working.Mark - As far s I know there is only one lasr in this machine, or at any rate on;y one laser lens, which I cleaned, although I haven't checked any individual diodes on the Pickup assembly, nor yet checked price/availability of a replacement Pickup assembly.
Of course I might be wrong about this specific machine, but based on my experience of DVD players, there will be two separate laser emitter diodes (650nm and 780nm). You won't be able to tell from a quick look, as they are buried deep inside the mechanism. There is only one lens visible from the top. On the Sony machines I own, you can display the hours of use of both lasers in service mode.
Failure of one diode only does happen. Of course, there is separate drive circuitry for each laser diode, so there could be a fault there. Or a poor connection somewhere that isn't carrying the drive current to the diode. Or the CD-specific servos could be out of alignment. But going deeper requires a service manual - a 30 second Google didn't seem terribly promising, but you have more of an incentive to search more thoroughly that I did...
Good luck,
Mark
