I have a pair of near identical NAD CD players. One that works perfectly (C521BEE), and another (C542) that does not play correctly and does not advance to the second and subsequent tracks.
I have taken eye patterns with my DSO on both machines. The difference between the traces is marked and it shows there is a substantial problem with the faulty machine.
Will a replacement laser cure the problem? Or could it be something else wrong?
There are no pots or other adjustments for me to tweak the laser.
They have differently labelled mechanisms, so I assume that the lasers are not interchangable?
Thanks.
I have taken eye patterns with my DSO on both machines. The difference between the traces is marked and it shows there is a substantial problem with the faulty machine.
Will a replacement laser cure the problem? Or could it be something else wrong?
There are no pots or other adjustments for me to tweak the laser.
They have differently labelled mechanisms, so I assume that the lasers are not interchangable?
Thanks.
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This is the serction from service manual. I hope this is what you are after?
I have taken a couple of additional traces of the faulty machine. One showing the eye pattern pattern better and the other showing the very noisy signal. It is certainly not a smooth wave!
I have taken a couple of additional traces of the faulty machine. One showing the eye pattern pattern better and the other showing the very noisy signal. It is certainly not a smooth wave!
Another reason for not take up such a swap is that the good laser/player may get damaged in the process and you end up with two "bricks".
I would leave the good player untouched.
I would suspect that the digital scope is the "culprit".
Same eye pattern from a good (P2P voltage wise) player:
- on analogue scope:
- on digital scope:
Thank you very much.
I looked at the connections and they were labelled the same. So, I did as you suggested and swapped teh mechanisms. I do not care for HDCD reading, so have no concern for if teh mechanism does or does not read them.
WORK PERFECTLY! The eye pattern is normal too.
So...
- the laser mechanism is faulty
- my Keysight DSO works perfectly and shows a perfectly acceptible eye pattern.
Result!!! I have a fully working C542 with the electro-luminiscent display. None of that modern LCD stuff, thank you.
I will now buy a cheapo transport and see if I can get the C521BEE back to life.
Thank you very much.