Monday, 23 September 2013

NAD 522 CD player laser adjustment

Even though there is no CNC involved in this subject, I feel that I should share this tip. This NAD 522 cd player was heading for the bin, but luckily I had the chance to intervene.

It refused to read most cds, with the ones that would being played with terrible distortion. As it turns out, it seems to be a common fault with this player: Rubbish at reading discs but sounds great when it works. NAD 522

It is the same fault that I fixed in my Kenwood DP-4030 about 20 years ago, which incidentally is still going strong. There is a potentiometer on the laser pickup board that adjusts the laser voltage.

If you are lucky enough to possess an oscilloscope it is easy to adjust the peak to peak value to 2.4V & ensure the waveform is focused. If not & you are like me, you just have to use your ears, though a voltmeter is helpful to record the resistance across the potentiometer. This helps not to lose your place as you adjust it. Too little voltage and your home recorded cds won't read & too much will saturate the signal resulting in distortion & a burnt out laser. It is a case of measuring the upper & lower limits of resistance & tuning the pot to the middle of the range.

Adjustments are entirely at your own risk & make sure you disconnect your equipment from the mains before opening the case.  Reader agrees to assume all risk resulting from the application of any of the information provided herein. By using this blog, the visitor agrees that the use of this web site and its information is entirely at his/her own risk.

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