NAD C541i laser tracking problem

[supernet]

Hello!


My NAD C541i player has great troubles to recognize the discs in a tray and number of songs. After some investigation, I replaced the laser (KSS 213D), clean all mechanism and put little teflon oil on steel pipe on which laser travels up and down. After reinstalation of the laser, CD player normally quick recognize the CDs and start playing...but quite funny...I can normally choose the songs from 1 to end, but if I want to go reverse (from song nr. 8 to 2), the laser move down and then start to loop cycling to find the track. Sometimes it find one sometimes not. Only way to go from nr.8 to nr.2 is to press stop button between, so laser can return to starting point.


What do you think could be wrong?


thx

 

[Mooly]

These are classic symptoms of an alignment issue, assuming there are no major mechanical issues.
The first step is too examine the quality of the RF or "eye pattern" on an oscilloscope, and to see what electrical adjustments are provided for. Focus bias and EF balance are the two most critical--- if adjustment is possible. If this is marginal then all kinds of problems occur.

 

[supernet]

Thanks.


I will try to borrow oscilloscope during weekend and check eye pattern.


Do you know maybe, where it is possible to find test track to test this?

 

[Mooly]

Any commercial CD is fine... you don't need a test disc. Try a few just to make sure you don't pick a particularly poor one ( low reflectivity ) The eye pattern will always look the same no matter what the disc contains.