On 31/05/2017 10:29 PM, Miguel Giménez wrote:
Hi

In the last years I have changed twice the laser unit of my Aiwa CD
reader and once the unit of my mom's Sony reader. The three were
original spare parts, and the three died months after.

Why this happen? Do I need to adjust laser current after change? Are
they basically unreliable?


**IME modern lasers are not reliable devices. The older ones were very
reliable. Why? Dunno exactly. If you look at an old laser from a Sony or
a Philips CD player, you will likely see a very carefully (hand
assembled?) laser unit, constructed from carefully machined aluminium
alloy, precisely aligned, using a high quality glass lens. Replacement
cost typically ran to several hundred Dollars. Modern lasers are all
made in China, from plastic and steel and are almost certainly machine
assembled. Cost, typically runs at around $20.00 or so. With massive
cost reductions in any product, something usually has to give.


--
Trevor Wilson
www.rageaudio.com.au