Philips DVD has a hard time detecting discs...

[Exo]

Hi,

I've got a philips dvd player wich has problems detecting discs. When a disc is inserted it will spin the disc for a while, then stop. Spin it again and so on for about 5 times. Then it says 'no disc'...

However every once in a while it does detect the disc and when it does it works perfectly. You can see an entire movie without a single glitch, no mather how many times you stop, start, select another scene ...

Anyone an idea of what might be causing this?

 

[Nigel Goodwin]

Hi,

I've got a philips dvd player wich has problems detecting discs. When a disc is inserted it will spin the disc for a while, then stop. Spin it again and so on for about 5 times. Then it says 'no disc'...

However every once in a while it does detect the disc and when it does it works perfectly. You can see an entire movie without a single glitch, no mather how many times you stop, start, select another scene ...

Anyone an idea of what might be causing this?

You could try cleaning the laser lens?, or the optical assembly probably requires replacement.

 

[Edmond]

As Nigel said, if the lens is clean then you have no chance to repair the laser-optic assembly. You must change it (or the DVD player).

 

[Edmond]

As Nigel said, if the lens is clean then you have no chance to repair the laser-optic assembly. You must change it (or the DVD player).

 

[Exo]

You could try cleaning the laser lens?, or the optical assembly probably requires replacement.

But it runs fine! ...
If the lens was damaged it wouldn't play a movie would it ?

 

[Nigel Goodwin]

You could try cleaning the laser lens?, or the optical assembly probably requires replacement.

But it runs fine! ...
If the lens was damaged it wouldn't play a movie would it ?

Quite possibly, once it's managed to read the TOC it can quite possibly read through the rest of the disk. The initial read of the TOC seems to give the most problems.

The first things I would do is:

1) Clean the lens and try it again.

2) Replace the laser/optical assembly, and try it then.

3) If neither of those cure it, then dig deeper (much deeper!).

However, more practically, if 1) didn't cure it I would probably just buy another DVD player - they are cheap enough these days, and Philips don't have a very good reputation!.

 

[Exo]

Got it to work...

On the small pcb where the lens is fitted on there's also a small smd potentiometer, by fiddling around with it i got it to work again...

I've seen such pots on almost all cd/dvd players, what do they control anyway. Laser focus, intensity ? ...

 

[TheOne]

Not a good idea to fiddle with this pot (without proper alignment instructions or laser power meter) as it sets the Laser Diode current and you can easily destroy the LD if you are not careful (LD's are also very static sensitive). The fact that you got it to work by adjusting indicates to me that the LD is on its way out.

 

[Nigel Goodwin]

Got it to work...

On the small pcb where the lens is fitted on there's also a small smd potentiometer, by fiddling around with it i got it to work again...

I've seen such pots on almost all cd/dvd players, what do they control anyway. Laser focus, intensity ? ...

As TheOne says, it's the laser power adjustment - it's not supposed to be adjusted outside the factory, it's actually part of the laser assembly, and comes pre-aligned. Turning it up is just masking the fact the laser needs replacing, and it's likely to drastically reduce any further life left in the laser (although it's not really a problem, as it's duff anyway!).

Very old CD Players had the laser power adjustment on the main PCB, and you needed a laser power meter to align it, the alignment was covered in warnings as the slightest setting too high is very likely to kill the laser.

 

[Exo]

I'll see what happens, perhaps it'll fail again in a few days, maybe it will work for years...

its just an smd pot; no glue on it ... it could've run off by itself (vibrations ,...)

 

[Nigel Goodwin]

I'll see what happens, perhaps it'll fail again in a few days, maybe it will work for years...

its just an smd pot; no glue on it ... it could've run off by itself (vibrations ,...)

Unlikely :lol:

But you've nothing to lose!.