I'm having some difficulty visualising how the suspension springs affect
the
laser's ability to focus on the disc. The relationship between the disc
turntable and laser height - and hence the mean focal distance for the
optical block's lens - is usually very firmly fixed. To this end, one of
two
methods is normally used. Either the laser slide rods are fixed firmly to
the deck, and the turntable motor is mounted on a spring-loaded subplate
with adjuster screws to allow the height and tilt to be set or, more
commonly, the motor is fixed, and the slide rods are spring loaded with
adjuster screws. Is it these springs that you are referring to ? If so, I
am
surprised that they would 'lose their spring' as they are normally quite
stiff types. I have had the deck suspension springs go 'soft' on many
different makes of CD andDVDplayers, but this tends to result in the whole
deck dropping with respect to the tray, which can result in either the
disc
clamp dragging, or the disc dragging on the tray. It can also make the
player very 'tap sensitive'.
Arfa
You know, as I think back on what I did, logic tells me that your
comment makes a whole lot of sense. But I also know what I did and
that it didn't work on any disk I put in, and then after stretching
the springs, it worked fine on any disk I put in it. Can't argue with
success. Maybe it is a very specific fix to this player, I don't
know, but time will tell as to how long it will last.
The original site I found the tip is here.
http://www.nerd-out.com/forum/viewtopic.php?t=28293&highlight=
WT
OK. Most of what the guy says makes reasonable sense. However, I believe
that his reasoning is utterly wrong as to why slack suspension springs under
the deck, will cause a problem. As I said previously, the relationship
between the optical block (laser assembly) and the disc turntable is very
accurately defined for any given deck assembly. Both the laser slide rods,
and the spindle (turntable) motor are very firmly fixed - albeit possibly,
but not always, with spring loaded adjustments being available - to the main
metalwork of the deck. That deck is then mechanically decoupled from the
rest of the player by springs, soft rubbers, or a combination of both. This
allows the deck to 'float' in a way that largely isolates it from external
vibration. Without this suspension being present, even walking across a
wooden floor might be enough to cause the deck to vibrate enough to
momentarily lose focus, although it is unlikely that you would see any
disturbance on the picture, due to the bit bucket that holds 'advance' data.
So, consider if one or more of the suspensions goes slack as that guy
suggests. Yes, the deck will now tilt compared to the previously
'horizontal' condition. But the trick is that as the deck tilts, so does the
laser and the motor. The disc clamp, being magnetic, is running in 'free
air' once the disc is clamped, so the disc will remain correctly flat on the
turntable. So in terms of spacial and angular relationship between the disc
and the optical block, nothing has changed. The effect is no different from
propping up one side or corner of the player on a matchstick laid flat.
However, that is not necessarily the end of the story. The relationship
between the deck and the tray, and between the disc clamp and its holder,
are *not* fixed. They *do* rely on the deck suspension to produce the
correct clearances. In this case, if the deck suspension springs / rubbers
wear or collapse, the result is often that the disc clamp will slightly rub
on its holder. This can be very slight, and leads to an erratic rotational
speed of the disc. This can, and does, cause the data stream coming off the
disc to be a bit 'scrappy', which can result in poor playability,
particularly on DVDs, which are more difficult for the player to read, than
CDs. If the drag becomes bad enough, the player can have difficulty spinning
up the disc fast enough to get a TOC read. Then you are in the situation of
it refusing to play discs. The same is true if the edge of the disc drags on
the tray, for the same collapsed spring reasons.
So, your stretching of the springs may well have cured this (common enough)
problem, but not for the reasons that you thought d;~}
Arfa