On Feb 11, 4:05*am, "Arfa Daily" wrote:
wrote in message

...
On Feb 9, 2:06 pm, "Arfa Daily" wrote:



"Tim Schwartz" wrote in message

...

wrote:
My Sega CD, which uses the KSS-240a laser assembly, makes a spine
chilling sound when it gets warm.. I believe it to be a cogwheel is
expanding when it warms up..

http://www.youtube.com/watch?v=U55FF7NLgn4

Any ideas on how to actually fix this? The system gets no hotter than
it normally does...

Hello,

One other thought that others have not mentioned. I've seen a failure of
the clock circuit being fed to the mechanism fail and cause the laser
sled
to go flying to the outside if the disc and the sled drive will keep
going. If left in this condition, it will actually grind the rack on the
laser to bits.

I've never had one that was intermittent, but if the clock was beginning
to fail, I guess it might do it for a short burst. If this is the case,
then the sled is likely to be at the extreme outside edge of the disc.

The machine that I've seen this on it the Arcam Alpha 8, and the Alpha
8SE
CD players. A surface mount transistor on the DAC board clock circuit
was
running to hot and would fail. When it did, the sled drive would force
the laser to the extreme outside and make a horrible ratcheting noise.
There was a production change to prevent this. I've NO IDEA if this is
possible on your Sega player.

Regards,
Tim Schwartz
Bristol Electronics

Hello Tim. Yes, I've seen a similar problem to that as well, but I can't
remember what it was on. As I recall, it chewed the teeth right off the
motor pinion. From what I can gather, this one doesn't seem to do it at
either end of the sled. Seems to be more when it starts to move the sled
from any position, so probably a mechanical issue.

Arfa

It's probably too late and Arfa won't see this, but I brought my whole
Sega CD to a repair shop, and he was able to reproduce the problem
when COLD.

With a scope, he discovered that the CD-ROM drive is in "seek" mode
when playing video games, hence the disc spins faster. *Possibly to
boost transfer rate for the games "Full Motion Video".

Also, he discovered the grinding will ONLY occur when the drive is in
it's "1.5x" mode, as when playing music CD's, the grinding was
impossible to produce.

Solution: *He has a replacement mech where the laser and PCB will
happily attach, and the Sega CD doesn't even know a different mech is
installed. *Only downside: *Tray is now white, and not black. *ehh..
As long as it works..

Good result then !

Arfa

PS: You don't think it would be stupid, for me to use my Sega CD as
my CD audio player? It does have great audio qualities, and it's
actually my only system in my theater, that can play CD's at such a
good quality. (even my HTPC can't compete!)

With specs like this:
16 bit DAC
8x internal over-sampling digital filter
Frequency Range: 20 Hz - 20 kHz
Signal-to-Noise Ratio: 90.0 dB @ 1K
Channel Separation: 90.0 dB

I assume that's good, because it sounds good.