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Braddy 5th February 2010 03:51 AM

Sony CDP-C433M, KSS 240A replacement.
I have a Sony CDP-C433M player that uses a KSS 240A laser unit.

The player was skipping & not finding discs until it got to the point where I couldn't use it at all. That was a few years ago.

I have finally got around to buying a new KSS 240A unit, however after I have installed it, the player still isn't working. On further inspection the disc isn't spinning at all, and the laser does not seem to be trying to focus.

At least the old one still tries to focus (laser moving up and down) but does't find the disc and the disc doesn't spin, although the spindle motor does sort of pulse. I have measured the spindle motor voltage and it is also pulsing at a very low level.

With the new laser unit there is no voltage on the spindle motor at all.

What is the process when a disc is inserted ? Does the laser look for the disc by adjusting focus (moving up and down), then when something is detected the spindle motor spins and the disc starts playing ?

Any idea why the new laser unit wouldn't be trying to focus ? Is it likely to be a faulty part that I should get swapped ?

Any assistance appreciated.

Mooly 5th February 2010 11:57 AM

The disc won't spin until focus is found... that's normal, it's easier to focus on a stationery object.
Sounds like it's duff or you have a damaged ribbon connector etc. If the other works if you put it back that's proof enough it's faulty.
KSS240's work "out of the box"

Just a mad thought... is the lens free, not sticky ?

Braddy 5th February 2010 10:38 PM

Thanks Mooly,

Sounds like a might have bought a dud, how frustrating. The ribbon cable must still be ok because if I put the old laser unit back in it definately attempts to focus, but obviously isn't working well enough to do so.

How do I determine if the lens is free ? I have been trying to avoid touching it with anything. Can it be moved manually without damaging it to determine that it isn't stuck ?

Braddy 5th February 2010 11:05 PM

Ok, I realised that I could move the lens by hand carefully by just touching the edge with my fingernail.

Everything seems to be working ok now. Part of the reason could have been the bigger ribbon cable within the unit that I had forgotten to plug back in (oops !) but that wasn't all because I had tried this before and sure I didn't leave it out each time.

Maybe the small manual movement just made the movement more free and it started to work. What ever it was I am pleased to report that things are now working as they should be.

Thanks very much Mooly for the confidence to try moving the lens by hand.

If nothing else, I have found a great active forum website for any Audio issues that I may be involved with in the future and hopefully we have helped someone else in the process.


Mooly 6th February 2010 04:49 PM

Really good to hear you have sorted it. Lenses sticking was an issue with some very early optical units... tbh this sounds more like the cable you forgot... yea oops :)

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