I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

Eric Cire wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

Probably not. Before you open it up, go buy a laser disk lens cleaner,
the kind that look like a CD with a little brush on it and use it.
DO NOT!!! touch the brush with your finger. This will transfer
skin oil to the lens.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

"Geoffrey S. Mendelson" wrote in message
...
Eric Cire wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and
noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open"
so
my question is:

Is there any laser radiation risk when the console/drive is turned off
and
unplugged?

Probably not. Before you open it up, go buy a laser disk lens cleaner,
the kind that look like a CD with a little brush on it and use it.
DO NOT!!! touch the brush with your finger. This will transfer
skin oil to the lens.

Geoff.


Sorry to be at odds with you on this one, Geoff, but I would STRONGLY
recommend NOT doing this. These cleaner discs are generally of little use in
terms of actually cleaning lenses, and on several occasions, notably with
Panasonic DVD drives, I have seen them cause additional damage, when the
little bristles get caught in the lens suspension wires, and then tear the
top off the optical block.

With the power off, there is absolutely NO danger at all of any laser
radiation. With the power on and the drive idling i.e. no disc in the drive,
or the disc not spinning, the laser will not be active. If you open and
close the drawer, the laser will burn briefly whilst it checks for a disc.
This represents absolutely no danger to your eyesight, as long as you don't
stick your eye 1cm above the lens, and look straight in. Observing a burning
CD / DVD read laser from an oblique angle is quite safe. I would not,
however, recommend getting your eyes anywhere near a disc burning laser.

The lens in your PS2 needs cleaning manually with a cotton bud (Q-Tip) and
isopropyl alcohol, but I doubt that this wil restore it. Unless you are a
heavy smoker and do not use the console very often, it is unlikely that the
lens is dirty, as drives that rotate the discs at high speed, such as DVD
drives, tend to self-clean due to the layer of high velocity air that the
rotating disc drags round under itself. Most likely, the laser needs
replacing. There used to be a number of places that supplied them at very
reasonable cost, and they are quite easy to fit. Whether they are still
readily available, I'm not sure, as I haven't replaced one for some time.
There was a couple of versions, as I recall, so if you do go down that
route, make sure you get the right one.

Arfa

(Geoffrey S. Mendelson) writes:

Eric Cire wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

Probably not. Before you open it up, go buy a laser disk lens cleaner,
the kind that look like a CD with a little brush on it and use it.
DO NOT!!! touch the brush with your finger. This will transfer
skin oil to the lens.

I wouldn't recommend lens cleaning discs.

It's worth the effort to open it and clean the lens manually.

The lens cleaning discs are not that likely to do any good and can do harm.

There is no danger of laser radiation when the thing is unplugged.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

"Sam Goldwasser" wrote in message
...
(Geoffrey S. Mendelson) writes:

Eric Cire wrote:
I'm thinking of opening up my old Playstation 2 console as I get
constant
"disc read error" and so been looking at this repair guide video and
noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when
open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off
and
unplugged?

Probably not. Before you open it up, go buy a laser disk lens cleaner,
the kind that look like a CD with a little brush on it and use it.
DO NOT!!! touch the brush with your finger. This will transfer
skin oil to the lens.

I wouldn't recommend lens cleaning discs.

It's worth the effort to open it and clean the lens manually.

The lens cleaning discs are not that likely to do any good and can do
harm.

There is no danger of laser radiation when the thing is unplugged.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above
is
ignored unless my full name AND either lasers or electronics is included
in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.


There's no danger unless your maybe eyeball is within about 2 mm of the
objective lens while it's focusing.

I'm reminded of a humorous variation of that sticker which reads,


"Warning! Do Not Look Into Laser With Remaining Eye!"


Mark Z.

Arfa Daily wrote:
Sorry to be at odds with you on this one, Geoff, but I would STRONGLY
recommend NOT doing this. These cleaner discs are generally of little use in
terms of actually cleaning lenses, and on several occasions, notably with
Panasonic DVD drives, I have seen them cause additional damage, when the
little bristles get caught in the lens suspension wires, and then tear the
top off the optical block.

I've never had that happen. Since live in a very dry, dusty climate, without
the cloud of hydrocarbons that surround most big cities, I don't get
the "sticky goo" type of dirt that you get on the lenses.

A light dusting off by a brush works wonders here.

Cleaning with isopropyl alcohol is a mistake, it makes mud out of the dust
and often leaves a residue. Ammonia based cleaners are illegal here.

I assume that if I lived in places like Philly (where I've lived) and London,
where I've visted, there would be a lot less dust due to the humidity
and a lot more "goo" due to the hydrocarbon cloud.

However, I've cleaned hundreds of CD-ROM drives and DVD players with them,
but have never come across one that was damaged by fibers breaking off.

YMMV.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

On Sun, 23 Mar 2008 05:54:54 -0400, "Eric Cire"
wrote:

I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

No power, no light, no problem. If you're seriously paranoid, you can
buy some cool looking laser eye protection safety glasses.
http://www.cyber-mag.com/station/laser.html

For PS2 CDROM repair instructions, see:
http://www.cyber-mag.com/station/laser.html
Tweaking the pots increases the laser driver current, which shortens
the lifetime. I've "fixed" some cdrom drives this way, only to have
some of them fail permanently after a few days.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sun, 23 Mar 2008 05:54:54 -0400, "Eric Cire"
wrote:

I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

No danger unplugged.

The lens cleaner discs are almost useless - only good if some dust
parks itself on the lens. But it is quick and easy and doesn't cost
too much. If that is the case, a good dusting of the whole mechanism
is probably in order.

Sometimes the lens can be cleaned with alcohol and a cotton swab - and
then the problem is often obvious, like a cloudy surface coating on
the lens that you can see. The lens has two sides and if the bottom
isn't sealed, or some residual vapor from manufacture are causing the
problem, it can become dirty and is impossible to clean.

Smoking, cooking, soldering, etc. - all will eventually cause a
problem.

Anything that interferes with focusing will also cause problems.

One of the over clocking web sites had a pretty good innovation for
running the case of desktops under positive pressure - versus the
normal negative pressure that sucks dust and smoke in. The guy
mounted three muffin fans outside his case on the side blowing in,
then used a large automobile carburetor filter over them to filter the
air he was pushing into the case. He put the fans so they were over
the processor and disk drives - looked a little unusual with the
"Edelbrok" air cleaner logo, but if it works . . .
--


----== Posted via Pronews.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.pronews.com The #1 Newsgroup Service in the World! 100,000 Newsgroups
---= - Total Privacy via Encryption =---

"Eric Cire" wrote in message
...
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and
noticed on top of the Ps2 DVD drive it says a warning "Laser radiation
when open" so my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?


Absolutely not.

Even with the drive plugged in and powered up, it's essentially a laser
pointer, just don't stare directly into it.

"Jeff Liebermann" wrote in message
...
On Sun, 23 Mar 2008 05:54:54 -0400, "Eric Cire"
wrote:

I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and
noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open"
so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

No power, no light, no problem. If you're seriously paranoid, you can
buy some cool looking laser eye protection safety glasses.
http://www.cyber-mag.com/station/laser.html

For PS2 CDROM repair instructions, see:
http://www.cyber-mag.com/station/laser.html
Tweaking the pots increases the laser driver current, which shortens
the lifetime. I've "fixed" some cdrom drives this way, only to have
some of them fail permanently after a few days.


For a lasting professional repair, tweaking the laser power pot is never a
recommended strategy for the short term failure reasons that you state.
There are a few exceptions to this rule - notably Pioneer lasers - where
setting the laser current is an official documented part of the overall
setup procedure.

Arfa

"Eric Cire" wrote in message
...
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and
noticed on top of the Ps2 DVD drive it says a warning "Laser radiation
when open" so my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?


Yes be sure to use a lead shielded suit! Just kidding.. It is not radation
in the sense you are probably thinking. Light is a type of radation and the
laser being a light of sorts, this is what they are refering to in this
case. As long as it is off you should be ok.. Even if it is on I think the
risk of eye damage is about that of using a laser pointer.

Mike

On Mon, 24 Mar 2008 00:30:22 GMT, "Arfa Daily"
wrote:


"Jeff Liebermann" wrote in message
.. .
On Sun, 23 Mar 2008 05:54:54 -0400, "Eric Cire"
wrote:

I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and
noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open"
so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

No power, no light, no problem. If you're seriously paranoid, you can
buy some cool looking laser eye protection safety glasses.
http://www.cyber-mag.com/station/laser.html

For PS2 CDROM repair instructions, see:
http://www.cyber-mag.com/station/laser.html
Tweaking the pots increases the laser driver current, which shortens
the lifetime. I've "fixed" some cdrom drives this way, only to have
some of them fail permanently after a few days.

For a lasting professional repair, tweaking the laser power pot is never a
recommended strategy for the short term failure reasons that you state.

Yep. However, there are three adjustments on most cdrom drives. The
laser current is not available on all models. However, there are
adjustments for the focus coil bias (sets the height) and servo loop
gain (sets ability to track warped disks). Both of these can be
adjusted to compensate for "normal" mechanical wear. See:
http://www.fortunecity.com/meltingpot/india/245/index5.htm
http://www.repairfaq.org/REPAIR/F_cdfaq7.html#CDFAQ_005

There are a few exceptions to this rule - notably Pioneer lasers - where
setting the laser current is an official documented part of the overall
setup procedure.

Umm... I don't think Pioneer has an accessible laser current (power)
adjustment. (I don't have a schematic or manual to be sure). I
couldn't find anything in Pioneer section of the RepairFAQ proceedu
http://www.repairfaq.org/REPAIR/F_cdfaq8.html#CDFAQ_014

Currently, it costs me less to replace a cdrom drive than it does to
repair one. So, I consider tweaking the various adjustments to be a
last-ditch heroic attempt to save the drive from the e-waste pile. If
it works (about 50% batting average), I win. If it doesn't, the
customer gets a new drive.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 3ÔÂ23ÈÕ, ÏÂÎç5ʱ54·Ö, "Eric Cire" wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

On 3ÔÂ23ÈÕ, ÏÂÎç6ʱ19·Ö, (Geoffrey S. Mendelson) wrote:
Eric Cire wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

Probably not. Before you open it up, go buy a laser disk lens cleaner,
the kind that look like a CD with a little brush on it and use it.
DO NOT!!! touch the brush with your finger. This will transfer
skin oil to the lens.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

On 3ÔÂ23ÈÕ, ÏÂÎç8ʱ39·Ö, Sam Goldwasser wrote:
(Geoffrey S. Mendelson) writes:

Eric Cire wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?

Probably not. Before you open it up, go buy a laser disk lens cleaner,
the kind that look like a CD with a little brush on it and use it.
DO NOT!!! touch the brush with your finger. This will transfer
skin oil to the lens.

I wouldn't recommend lens cleaning discs.

It's worth the effort to open it and clean the lens manually.

The lens cleaning discs are not that likely to do any good and can do harm..

There is no danger of laser radiation when the thing is unplugged.

--- sam | Sci.Electronics.Repair FAQ:http://www.repairfaq.org/
Repair | Main Table of Contents:http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ:http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites:http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

For a lasting professional repair, tweaking the laser power pot is never a
recommended strategy for the short term failure reasons that you state.

Yep. However, there are three adjustments on most cdrom drives. The
laser current is not available on all models. However, there are
adjustments for the focus coil bias (sets the height) and servo loop
gain (sets ability to track warped disks). Both of these can be
adjusted to compensate for "normal" mechanical wear. See:
http://www.fortunecity.com/meltingpot/india/245/index5.htm
http://www.repairfaq.org/REPAIR/F_cdfaq7.html#CDFAQ_005

There are a few exceptions to this rule - notably Pioneer lasers - where
setting the laser current is an official documented part of the overall
setup procedure.

Umm... I don't think Pioneer has an accessible laser current (power)
adjustment. (I don't have a schematic or manual to be sure). I
couldn't find anything in Pioneer section of the RepairFAQ proceedu
http://www.repairfaq.org/REPAIR/F_cdfaq8.html#CDFAQ_014

I was talking more in terms of CD player lasers when I referred to Pioneer.
On almost all of their models, adjustment of the tiny laser power pot on the
flexiprint that goes down to the main board, is a proper part of the
adjustment procedure. I was just trying to convey to to the less experienced
readers, that it is an exception rather than a rule, to adjust laser power.
I was interested to know exactly what wear you feel warrants adjustment of
the focus bias (offset) ? I would agree that it doesn't hurt to slightly up
either tracking or focus gain, to improve 'playability' with some discs. The
setting of these controls is something of a 'manufacturing compromise' in
the first place to ensure that the servos have sufficient gain to maintain
lock under all conditions, without causing the lens suspension and drive
coils to 'whistle' too much on marked discs. However, short of serious wear
in the spindle motor causing the turntable to drop, I can't think of any
wear that would indicate a change in focus bias being needed ? The focus
servo has a pretty wide 'window of lock' anyway to accommodate warped discs,
so tiny amounts of wear in the motor will not have a lot of effect on the
nominal focus point.

Arfa

On 3ÔÂ23ÈÕ, ÏÂÎç5ʱ54·Ö, "Eric Cire" wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

On 3ÔÂ23ÈÕ, ÏÂÎç5ʱ54·Ö, "Eric Cire" wrote:
I'm thinking of opening up my old Playstation 2 console as I get constant
"disc read error" and so been looking at this repair guide video and noticed
on top of the Ps2 DVD drive it says a warning "Laser radiation when open" so
my question is:

Is there any laser radiation risk when the console/drive is turned off and
unplugged?



Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com

On Mon, 24 Mar 2008 11:21:16 GMT, "Arfa Daily"
wrote:

For a lasting professional repair, tweaking the laser power pot is never a
recommended strategy for the short term failure reasons that you state.

Yep. However, there are three adjustments on most cdrom drives. The
laser current is not available on all models. However, there are
adjustments for the focus coil bias (sets the height) and servo loop
gain (sets ability to track warped disks). Both of these can be
adjusted to compensate for "normal" mechanical wear. See:
http://www.fortunecity.com/meltingpot/india/245/index5.htm
http://www.repairfaq.org/REPAIR/F_cdfaq7.html#CDFAQ_005

There are a few exceptions to this rule - notably Pioneer lasers - where
setting the laser current is an official documented part of the overall
setup procedure.

Umm... I don't think Pioneer has an accessible laser current (power)
adjustment. (I don't have a schematic or manual to be sure). I
couldn't find anything in Pioneer section of the RepairFAQ proceedu
http://www.repairfaq.org/REPAIR/F_cdfaq8.html#CDFAQ_014

I was talking more in terms of CD player lasers when I referred to Pioneer.
On almost all of their models, adjustment of the tiny laser power pot on the
flexiprint that goes down to the main board, is a proper part of the
adjustment procedure.

Well, I'll admit that I've never read or seen the official adjustment
procedure.

I was just trying to convey to to the less experienced
readers, that it is an exception rather than a rule, to adjust laser power.

Agreed.

I was interested to know exactly what wear you feel warrants adjustment of
the focus bias (offset) ?

I have a home made laser output measuring device. It's just a tiny IR
photodetector on the end of a plastic stick that I can shove into the
drive when it's running. That gives me an indication of the laser
output as it's looking for a disk. I've noticed that on some models
(i.e. Panasonic) the output was rather low. So, I cranked it up and
magically fixed a few cdrom drives. Unfortunately, my guess(tm) that
what's happening is that the laser diode has partially unglued itself
from the substrate, thus causing excessive heating and eventual
failure. I don't have the equipment (or talent) to do the necessary
autopsy to be sure. However, the subsequent total failure of the
drive after my adjustment seems to suggest that the diode was on its
way out, and I just accelerated the process. Incidentally, there's a
very noticeable apparent drop in laser output when comparing old and
new drives. It's impossible to tell how much using my home made
tester.

Adjustment of the gain and offset pots is to compensate for dirt in
the focus mechanism and mechanical damage caused by various cleaning
aids. There can also be some wear on the traveler rails and head
assembly if the drive does considerable seeking. I used to maintain
an array of 12 SCSI cdrom drives acting as a database server. (This
was before cheap DVD's). The CD's were changed (updated) roughly
every week. The drives were constantly seeking, making wear a
possibility. Drive lifetime was about 2 months after which I started
getting initialization errors. I initially compensated by tweaking
the gain and bias, which bought me another week or two. Eventually, I
compared the run-out and position of the traveler with a dial
indicator and found that it had substantial irregular wear. I
switched to a molybdenum disulfide based grease lubricant, and largely
eliminated the wear and tear. Unfortunately, the system was upgraded
to an array of DVD drives, and I only had about 3 months of operating
time for testing. There were no seek failures during the 3 months. I
saved some of the worn out drives (because SCSI CDROM drives are
difficult to find).

There's some stuff on adjustments at:
http://www.cyber-mag.com/station/laserPS2.htm

Back then, SCSI CDROM drives were about $250/ea so it was well worth
doing the repairs. (I think I paid $600 for my first 1X cdrom drive
with a tray and proprietary controller card). Today, cdrom drives are
about $30 and not worth fixing. The exception are drives that have
been "propietarized" for use in dedicated hardware, such as various
game machines. Also those that have unique plastic cosmetic parts
that are difficult to find. As I previously indicated, the only
reason I tweak the various adjustments is in vain hope of preventing
the drive from becoming e-waste.

I would agree that it doesn't hurt to slightly up
either tracking or focus gain, to improve 'playability' with some discs. The
setting of these controls is something of a 'manufacturing compromise' in
the first place to ensure that the servos have sufficient gain to maintain
lock under all conditions, without causing the lens suspension and drive
coils to 'whistle' too much on marked discs.

Adjusting the gain and bias seems to increase the range of travel,
which is what compensates for the wear.

However, short of serious wear
in the spindle motor causing the turntable to drop, I can't think of any
wear that would indicate a change in focus bias being needed ? The focus
servo has a pretty wide 'window of lock' anyway to accommodate warped discs,
so tiny amounts of wear in the motor will not have a lot of effect on the
nominal focus point.

Well, according to what I've read and seen, that's exactly what
happens(1). The traveler wears down as it slides along the rails. The
wear isn't much, but sufficient to impair focus with a warped or
marginal cdrom. However, I don't think that's the only source of
deterioration. A decrease in laser output, filth in the optics, wide
variations in reflectivity from various media, and bad cd burns, all
contribute to read errors.

Disclaimer: I are not an expert on cdrom operation and repair.

(1) Next chance I get, I'll tear apart a traveler from an old and well
used cdrom drive and stuff it under the big inspection microscope at
the local machine shop. It should easily tell me how far out of round
the holes have worn.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

snip

However, short of serious wear
in the spindle motor causing the turntable to drop, I can't think of any
wear that would indicate a change in focus bias being needed ? The focus
servo has a pretty wide 'window of lock' anyway to accommodate warped
discs,
so tiny amounts of wear in the motor will not have a lot of effect on the
nominal focus point.

Well, according to what I've read and seen, that's exactly what
happens(1). The traveler wears down as it slides along the rails. The
wear isn't much, but sufficient to impair focus with a warped or
marginal cdrom. However, I don't think that's the only source of
deterioration. A decrease in laser output, filth in the optics, wide
variations in reflectivity from various media, and bad cd burns, all
contribute to read errors.

Disclaimer: I are not an expert on cdrom operation and repair.

(1) Next chance I get, I'll tear apart a traveler from an old and well
used cdrom drive and stuff it under the big inspection microscope at
the local machine shop. It should easily tell me how far out of round
the holes have worn.


Hmmm. That's interesting. I must admit that I hadn't considered wear on the
slide holes or the 'claw' and its runner, if that is what a drive uses on
one side. Most decks that I see are from audio equipment, so do not get the
hammering that you are saying that these of yours did. I think that the wear
would still have to be pretty substantial to significantly affect the focus
bias point on all but the most warped discs. Some of the worst that I've
seen still only cause a deviation of say +/- 1mm of the lens with the
optical block at the outside edge of the disc. Considering that a 'blind'
focus search - i.e. with no disc inserted - results in a lens movement of
probably +/- 2mm, you would have expected that the focus servo would be able
to lock over at least that range. In fact, thinking about it, I know that it
can on many players, because I have held a disc over the top of a deck
that's out of a player, to watch the focus search taking place, and the
focus locks easily and you can then pull the lens up and down as though on
elastic, a considerable amount, before the servo loses lock and the lens
'breaks free'.

Many, although not all, audio lasers use a phosphor bronze sleeve bearing to
run on the slide rod, which is actually *very* hard chrome plated, so I
would not expect them to wear anything like as badly as the ones where it is
just plastic running on the slide rod.

Have you ever tried adjusting tracking (E-F) and focus balance by ear ? It's
actually very easy to do on an audio player, and is remarkably accurate,
when checked against the eye pattern on a 'scope. If you use a scuffed disc,
and turn up the tracking and focus gains a little, the servos will make the
lens suspension 'whistle' as it tries to follow the imperfections on the
disc surface. If you then stick your mark one ear'ole down near the laser,
and tweak the focus and tracking balance controls back and forth a little,
you can hear a very distinct and sharply defined 'null' in the noise. Set
the controls there, and then turn the tracking and focus gains back down to
where they were. Give it a try. You'll be amazed at how simple and accurate
it is.

Arfa