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[tomoco]

Anyway, getting back to "ORO's" original problem of his car cd player struggling to play his CDR's. Try to record (BURN) them slower. Most cd burning software will let you adjust the burning speed before you start burning to disc. Even though most blank cd's you buy these days have a lable saying 52X, you should never burn audio discs at anyway near that speed. Try much slower (i'm talking 4X or even 2X) its takes a bit longer but you get better quality (because the lazer can find the tracks a lot easier) and you get less errors (coasters). I burn all my car cd's at 4X with no problems what so ever.

Mark

P.S. try a cd lens cleaner before you through all your existing cdr's away.

P.P.S. Dont use  CDRW's the format (the way the data is set down on the disc) is different so most of the older pre 2004 in car units will struggle with this type of disc.

hope this helps

[Marks DTM Calib]

CDR's reflect less light to the detector than pressed CD's (upto about 1/4 of the light) and so not all CD player receivers can tolerate the lower light output.

In theory, better discs and slower burn speeds help increase the light levels but they are never going to be as good as originals.

You might get lucky and have a player with a more sensitive PIN diode/transimpedance amp setup but, most older players are not designed to this criteria.

Cant get my head around any mechanism that would shorten the life of the player though as the laser 1's level and bias is constant.....

[Dave DND]

Cant get my head around any mechanism that would shorten the life of the player though as the laser 1's level and bias is constant.....

Its the laser focus coils that burn out as they struggle to see the smaller dots. Laser power is indeed constant. If you fancy a technical challenge to see what I mean, hook up a scope to the focus / tracking test points and observe the difference in activity between the two formats.

[Marks DTM Calib]

Cant get my head around any mechanism that would shorten the life of the player though as the laser 1's level and bias is constant.....

Its the laser focus coils that burn out as they struggle to see the smaller dots. Laser power is indeed constant. If you fancy a technical challenge to see what I mean, hook up a scope to the focus / tracking test points and observe the difference in activity between the two formats.

Thanks Dave, will have a nose at that.....

Been trying to recall my CD principles knowledge......do they still apply a control tone to the laser rather than operate CW?

[Dave DND]

Most of the In Car stuff does not need an external control tone, (but yes to your question) as pretty much all of them nowadays have an inbuilt test mode allowing you to view the S curve without the need of a signal generator. One less bit of kit to hook up.

[Kevin Wood]

It's quite interesting watching the control systems in a CD player working. They're an impressive bit of control system design, and it's remarkable that they work as well as they do, really.

Kevin

[Marks DTM Calib]

It's quite interesting watching the control systems in a CD player working. They're an impressive bit of control system design, and it's remarkable that they work as well as they do, really.

Kevin

Pretty slow and simple stuff realy though.......by modern standards.

I suspect the lasers would be considerably more reliable if they had proper control systems to....but that would add cost.

[TheBoy]

It's quite interesting watching the control systems in a CD player working. They're an impressive bit of control system design, and it's remarkable that they work as well as they do, really.

Kevin

Pretty slow and simple stuff realy though.......by modern standards.

I suspect the lasers would be considerably more reliable if they had proper control systems to....but that would add cost.

I'm guessing cost is most important factor, but also weight if it has to be on laser itself to allow for fast adjustments with less inertia?

[Kevin Wood]

I'm guessing cost is most important factor, but also weight if it has to be on laser itself to allow for fast adjustments with less inertia?

The fast stuff just moves the lens on the players I've destroyed serviced. The laser itself is on a fairly slow-moving sled. However, more weight means it will be more sensitive to shock.

Kevin

[TheBoy]

I'm guessing cost is most important factor, but also weight if it has to be on laser itself to allow for fast adjustments with less inertia?

The fast stuff just moves the lens on the players I've destroyed serviced. The laser itself is on a fairly slow-moving sled. However, more weight means it will be more sensitive to shock.

Kevin

I was thinking for finding the spiral, and constant adjustment to stay on it?

[Kevin Wood]

I'm guessing cost is most important factor, but also weight if it has to be on laser itself to allow for fast adjustments with less inertia?

The fast stuff just moves the lens on the players I've destroyed serviced. The laser itself is on a fairly slow-moving sled. However, more weight means it will be more sensitive to shock.

Kevin

I was thinking for finding the spiral, and constant adjustment to stay on it?

The lens does that, in conjunction with the sled, normally. There are usually 2 sets of "voice coils" connected to the lens that move it up and down (to focus the laser (or, more accurately, the reflection on to the sensor) and side to side to keep the laser aligned with the track. These follow any warp or eccentricity of the disc too.

The sled is then used for coarse positioning of the laser, to keep the "left/right" control system within its operating range.

I think Mark was referring to controlling the current through the laser to get an adequate signal, rather than just running it flat out all the time?

Kevin

[TheBoy]

I'm guessing cost is most important factor, but also weight if it has to be on laser itself to allow for fast adjustments with less inertia?

The fast stuff just moves the lens on the players I've destroyed serviced. The laser itself is on a fairly slow-moving sled. However, more weight means it will be more sensitive to shock.

Kevin

I was thinking for finding the spiral, and constant adjustment to stay on it?

The lens does that, in conjunction with the sled, normally. There are usually 2 sets of "voice coils" connected to the lens that move it up and down (to focus the laser (or, more accurately, the reflection on to the sensor) and side to side to keep the laser aligned with the track. These follow any warp or eccentricity of the disc too.

The sled is then used for coarse positioning of the laser, to keep the "left/right" control system within its operating range.

I think Mark was referring to controlling the current through the laser to get an adequate signal, rather than just running it flat out all the time?

Kevin

I did lightly look into it all many years ago.  Trouble at my age is that to fit new knowledge in to my mush pit in my head means some old knowledge has to drop out.  I hope knowledge of vital body functions doesn't drop out....

[M16]

Hey. I had same problem. If I copied one of my cd's on my laptop the car cd would not play it at all. All i did was buy an external CD/DVD copier from maplin and problem solved. Car now plays copies. It all depends on what sort of CD Writer you have. I now use a Argosy External (Cost £35). Bit better than a new car cd player lol

[file28]

you're not one of terrys togs are you ? anyway i prefer to listen to radio 2 also where else can you listen to the full version of stairway to heaven without going digital

We all know the reasons why we use CDR's CDRW's etc, it's because we can get them cheap from someone at work or we burn them ourselves from the net.
The cost of a new CD in the shops are stupidly high & so whatever the costs are involved in getting the unit repaired will probabley be cheaper than buying full price CD's

no, mine is because my cd collection sits indoors and stays there.  With 3 cars to fill, all only having '6 disc' changers, i like to make my own compilations.  I would say 99% of my music is bought.  Don't buy so much now, as its all crap, but thats coz I've turned in to Radio2 man (Mainly coz I cant stand Moyles and the scottish bimbo after him).

[Marks DTM Calib]

Yes, there was a method used on high end CD players where the laser was modulated with a tone so the diode had to be biased at the knee point (all laser diodes operate as an LED until they reach a threshold where the current climbs fast and they lase) and then the modulation applied.

The theory was that it is easier to recover the digtal signal because you could just look for the signal strength of a known tone (filter it!), it also made focusing easier because you adjusted to maintain the maximum control tone at the 1's level......

Having worked with comms laser based transmision systems for some 10 years now (we work up to 10G directly modulated and 40G via modulators!) the CD player setups are very old hat and simple!