Sam Goldwasser wrote:
"dave" nospam writes:

Hey Afra,

You may have me there. I've only repaired two CD changers. One
Yamaha had a hairline crack on the stepper motor gear that caused it
to skip intermittently. One Denon did have bad tray sensor
switches. It had a hard time loading disks because of it.

But my point was more to do with the way some things are blanketly
diagnosed. I have much more tape machine background. I don't know
how many times a lay person would hand me a bad tape machine and
tell me it probably just needs the heads cleaned. I'd be like "sure
I'll clean the heads for you. How about I fix it after that?"

DaveL


I remember there were some Sony models (I think) where the speed of
the motor that rotated the corousel would drift with time and then
the player wouldn't even recognize that there was a disc in any
position. A resistor/pot
fixed that.

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"Arfa Daily" wrote in message
...

"dave" nospam wrote in message
. ..
Sam is correct. Let's see, the player does not detect CDs so
check the lense for dust? It could be a bad laser? Not even
close! CD changers generally have sensors to tell them which
slots have disks in them. I'd check those sensors first. Also
the change/loading mechanism could have sensor switch problems.

DaveL


Sam, or indeed you, *may* be correct - it depends on what exactly
the OP means by the player " failing to detect a disc ". In my
experience, this is normal-speak for the player not extracting a
TOC from a disc, maybe after a spin-up, maybe not even getting that
far. It is very very rare for a player that has separate disc
detection, to fail to sense that a disc is on the carousel at any
particular position. Many players do not have separate disc
detection sensors, relying on the laser to find something when it
initiates a focus search. This particular player does use separate
optical sensors for both disc and carousel position detection.
However, I can't remember ever having a problem with one failing to
sense discs on the carousel.

Having repaired many of these, I would fire the same statement of "
not even close ", back at you. In my experience, the most common
playing problem on these is due to a defective ( or just plain
dusty ) KSS240A, and the liklihood of any sensors being at fault is
slim at best. I have had the laser flexiprint go bad, and that
usually results in failure of the focus motor to operate, as the
tracks that normally break are the ones that connect to there. This
is easily spotted by watching to see if the lens goes up and down (
having first fooled the sensor into thinking that there is a disc
in place, of course ...) Very often, a poke of the flexiprint at
that point in time, will cause the tracks to momentarily remake,
and the lens will move.

And to Sam, yes, I would say that the situation is that bad now. The
quality of the 'standard' Sony KSS series lasers, fitted to many
manufacturer's products, seems to have gone down and down over the
years, and I change many of them - often in kit that's still within
the warranty period, which is often about the only time that it's
financially viable to do it. The latest Sony offering in the laser
stakes, is not even replaceable. The flexiprint is solder-attached
at both ends, so the whole assembly has to be replaced, complete
with the servo / amp pcb, which also is not really servicable, as
the IC is one of those calculator style " ball of snot " jobs, that
has no visible pins for measuring on.

Arfa

Also on these Sony models the inside limit switch can be flaky or
inoperative. The disc just spins and does nothing else 'til the limit switch
hits.

MarkZ.