Tools that cannot work

[Max Demian]

Some time ago I bought an i-Star Multi Lens Cleaner Disc with Fluid. Just now I tried it on my laptop drive which was malfunctioning, and it had no effect. It is a 5" disc with little brushes that you moisten with detergent fluid provided; you are supposed to insert it and press play (or whatever). It then is supposed to clean the lens and then play a little tune and/or play a video and say it has finished (though that isn't mentioned in the instructions).

On examining it appears that the brushes are in the wrong place; they are near the edge of the disc. Optical players always start reading in the centre where there is some kind of index track; if it can't be read it will keep chugging away until it gives up or you eject the disc. If the lens is dirty, it will never reach the brushes to be cleaned!

I notice that it's unavailable now except from eBay:

of the pictures show the brushes.)

Fortunately the lens assembly of my laptop drive is easily accessible so I cleaned it with a cotton bud and isopropyl alcohol and it's working fine now, but I have drives where the lens isn't accessible so I may have to buy a cleaner disc.

Amazon advertise an ALLSOP model for £7.99+p&p where it looks like the brushes are in a better position, and Wilko advertise one for £3 - I don't know whether that one will work.

Has anyone any experience with these cleaners?

[Theo]

How do you know it's not doing that? If it's readable as an audio disc, for example, the table of contents could say that track 1 starts at 60m0s or whatever is near the edge of the disc, and the drive will try to play from there.

There may be a reason for using the edge of the disc, depending on whether your drive is Constant Linear Velocity or Constant Angular Velocity.

If you're using it in a laptop you presumably aren't 'playing' it like an audio player would - a long time ago computer drives had the same playing functionality as audio drives and run at native CD playback speed, including a DAC with an analogue output, but nowadays there's no audio path - the computer just reads the data off the disc as fast as possible and does its own playing like you would play a WAV file.

It sounds like a product designed for a different age with assumptions about what older generations of players do. But then these things were always a bit of a hack - the CD spec did not expect discs to come with brushes on them!

Theo

[Max Demian]

If the lens is dirty, it won't be able to find out where track 1 starts. And I'm pretty sure all optical discs are read from the centre outwards, using a spiral pattern of pits.

[billy bookcase]

IME yes the discs do work "eventually" and without the cleaner.

I bought a Hama brand disc off eBay

It has two brushes one long one short positioned half way across the disc, As the laser scans the entire disc I'm not sure positioning is critical.

When first loaded it simply made a noise with nothing on the screen.

When reloaded it again made a noise and then gave you a crude languages menu which was static

When reloaded it again made a noise and then gave you a crude languages menu which could be selected from. Not that this ever made any difference.

Eventually ....

When reloaded it again made a noise and then gave you a crude languages menu which could be selected which then brought up a crude animation of dust particles being removed from the disc.

After which, the disc loaded and played o.k

On using it again it was any combination of the above - but it eventually did the job.

bb

[Brian Gaff (Sofa]

The ones I have seen had two sets of brushedes, one near the middle and one on the outside. Surely, if the brushes are where the indexing tract is near the middle the track cannot also be there. In many players, but not all the head is driven out and back several times in an attempt to pick up the index again. I suspect this was what the one brush system was expecting to happen. I do not see how the two brush ones every fond a track at all, unless it was meant for a non finalised disc like a multi session or a dvd recorder which seem all to have this hunting system. I don't know enough about how this works, but after many years of recording on tdk and maxell blank cd discs, suddenly one, a batch of Maxell have stopped working in one drive even though the last batch still did. . Very odd as they function in some other drives fine. Brian