CD Player laser fault/misdiagnosed (SHANLING S100)

[nathanjh13]

Hi, thanks for reading.

I have a Shanling CD S100 using, I believe, a Philips 12.1 transport and a Sanyo SF-HD850 optical pickup.

The noise of the laser reading the disk is fairly loud. It's not too bad at normal listening levels but it's still there. The noise is constant when in PLAY but when in PAUSE it's less frequent but still fairly regular.
I've attached a sound clip (NOTE the mic is pretty close to the cd player here).

http://sites.google.com/site/nathanj...inningBeep.WAV

I'd read that changing the laser fixes the problem. I did this but I've exactly the same problem

If I change the transport etc will this cure it or am I stuck to a Philips 12.1 (or VAM1210) and Sanyo as above, hoping I finally find a comination that works?

I wonder if it's when the laser "pops up" to read and it catches the surface of the disk?

Any help is appreciated. Thanks
Nathan

[Mooly]

Hmmm... the sound clip would be better with just the player and less background/music

The noise is that of the servo system and is audibe because of the coils (tracking/focus) on the lens assembly. You need to be sure the discs are 100% perfect and clean. Any scratches can give a burst of noise from the servo as the system tries to correct for tracking/focus errors. Does the disc run perfectly true with no wobble or run out when viewed edge on ?

I am puzzled with the references to the CDM12.1 and Sanyo pickup. The CDM12 is a Philips unit and has no connection with anything Sanyo.

CDM12.1 here,
cdm12.1 - Google Search

Sanyo here,
Sanyo SFHD 850 - Google Search

[nathanjh13]

Thanks Mooly.

The unit makes the same noise regardless of the condition of the disk (even brand new). I diagnosed the transport type from all the reviews I've seen, such as this:

Product Review

but if it's different then fair enough (pics below).

The laser I replaced was the Sanyo one but I'm not sure what to make of it all now.

Is it as simple as buying a cdm12.1 as shown in your link, with the laser assembly and sled attached (or a VAM1210 if easier to find) and that's it?

[Mooly]

It's not a Philips CDM12 for sure.

Not familiar with the unit, but, looking at the large ribbon connector to the pickup I wonder whether this is in fact a DVD drive (which many manufacturers use for both good performance and cost), in which case they can be a little noisy in my experience,

[nathanjh13]

Thanks. To tell the truth I only looked up the transport type recently and long after replacing the laser (so convinced was I that it was the laser).

Do you reckon, I'd be better off using another transport and pickup in there instead? They're cheap enough and I've so far had bad luck with both attempts with this one. Is a straight switch like this possible or not so good an idea looking at the circuitboard fixed to it etc.

If the other Shanling units as per the reviews are anything to go by, a 12.1 should "fit"?

I'm now, and was a little before, out of my depth.

Apparently it's a HDCD so the wider ribbon may explain it but yes, I think it's a DVD pickup.

Thanks

[oshifis]

I read in another thread that too high focus gain and tracking gain causes such noise. The advice was to turn down the corresponding pots until the noise just disappears. Another suggestion was to monitor the eye pattern, turn down the pots until the eye pattern envelope starts to be uneven, then turn up until just becomes quiet.

[Mooly]

Originally Posted by oshifis

I read in another thread that too high focus gain and tracking gain causes such noise. The advice was to turn down the corresponding pots until the noise just disappears. Another suggestion was to monitor the eye pattern, turn down the pots until the eye pattern envelope starts to be uneven, then turn up until just becomes quiet.

Correct... but... you really need to understand what you are doing. Tracking gain and focus gain have no direct effect on the visible quality of the eye pattern (RF) and will work within a wide range of adjustment, but that doesn't mean they are correct.
If the focus gain is to high then the pickup can become noisey (usually white noise... hiss). An experienced tech can get it pretty near spot on just by listening to the pickup. Tracking gain is more difficult and examination of the tracking error waveform will reveal the presence of a low frequency fundamental wave appear as the gain is turned up. Again an experienced tech can set the gain using this as a guide and adjusting the gain up to the point that the LF wave form appears. That can even be done by listening to the TE signal via an amp and speaker as unbelievable as it sounds in the absence of having a scope. There may be other adjustments... EF balance and offsets and really without the equipment and experience the only way is to have a manual. Focus bias is critical and has a direct effect on the signal... a scope is the only way to adjust this.

I suspect the noise is going to be something that can not be eliminated fully rather than a fault.

Fitting another type of pickup is a non starter... the whole of the servo and electronics is built for that one device only. They are as different as can be in every possible respect.

[nathanjh13]

No prob, thanks for that. I suspected a switchover would be a problem, I'll soldier on, at worst trying another identical transport etc in place of this one. Failing that, there' Shanling S100 going cheap on Ebay soon.

Cheers
Nath

[georgehifi]

That looks to me like a Sanyo SF-HD65 Mech, cheap as chips with laser $25

Cheers George

[georgehifi]

And the Laser is the again SF-HD65 also cheap as chips and $15

Cheers George