First time for years (no salvaged one on hand) I replaced old with new but
had forgotten about those antistatic shorting links, wasting time trying to
find the short. Nothing on the box about the shorting link, only graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone to static
damage?

On Wed, 22 Dec 2010 08:55:50 -0000, "N_Cook"
wrote:

Is there something in the laser assembly that is especially prone to static
damage?

Directly adjacent to the laser is a spinning piece of plastic
sometimes referred to as a CD or DVD. Like all good plastic parts,
it's quite capable of turning into a Van de Graaff generator. The
rubber pad on the center spindle is slightly conductive and bleeds
away some of the static charge, but some charge may accumulate.

There is also a substantial chance of discharging static electricity
from your body in the process of inserting or removing the CD. Since
the optics are exposed during the insertion, they must be protected
against being the first point of contact.

Some applicable patents.
http://www.google.com/patents/about?id=XjoWAAAAEBAJ&dq=5684775
http://www.google.com/patents/about?id=5PcmAAAAEBAJ&dq=5684775
(etc...)
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"Jeff Liebermann" wrote in message
...
On Wed, 22 Dec 2010 08:55:50 -0000, "N_Cook"
wrote:

Is there something in the laser assembly that is especially prone to
static
damage?

Directly adjacent to the laser is a spinning piece of plastic
sometimes referred to as a CD or DVD. Like all good plastic parts,
it's quite capable of turning into a Van de Graaff generator.

So you need to leave the anti-static shorting links on when its operating
then?

I thought they were just for transit and handling!

Ian Field wrote in message
...

"Jeff Liebermann" wrote in message
...
On Wed, 22 Dec 2010 08:55:50 -0000, "N_Cook"
wrote:

Is there something in the laser assembly that is especially prone to
static
damage?

Directly adjacent to the laser is a spinning piece of plastic
sometimes referred to as a CD or DVD. Like all good plastic parts,
it's quite capable of turning into a Van de Graaff generator.

So you need to leave the anti-static shorting links on when its operating
then?

I thought they were just for transit and handling!




And for confusing absent minded electronic engineers.
The whole unit was in an antistatic bag for transit purposes, inside the
box, so whatever these links are for is for just the mechanical fixing and
connecting in cables, with m/c off -line off course.
I'd never considered any problems associated with mini Wilmshurst
generators.

"N_Cook" writes:

First time for years (no salvaged one on hand) I replaced old with new but
had forgotten about those antistatic shorting links, wasting time trying to
find the short. Nothing on the box about the shorting link, only graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone to static
damage?

Yes, the laser diode. There's generally very little circuitry between the
cable and laser diode and it can be damaged by any number of things including
ESD.

--
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.

"Ian Field" wrote in message
...

"Jeff Liebermann" wrote in message
...
On Wed, 22 Dec 2010 08:55:50 -0000, "N_Cook"
wrote:

Is there something in the laser assembly that is especially prone to
static
damage?

Directly adjacent to the laser is a spinning piece of plastic
sometimes referred to as a CD or DVD. Like all good plastic parts,
it's quite capable of turning into a Van de Graaff generator.

So you need to leave the anti-static shorting links on when its operating
then?

I thought they were just for transit and handling!


It is just for transit and handling. Ideally, one removes the short AFTER
the pickup is connected to an approriate circuit. Sometimes this is
impossible, and a anti-static grounding strap is needed while installing.

Mark Z.

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:

First time for years (no salvaged one on hand) I replaced old with new
but
had forgotten about those antistatic shorting links, wasting time trying
to
find the short. Nothing on the box about the shorting link, only graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone to
static
damage?

Yes, the laser diode. There's generally very little circuitry between the
cable and laser diode and it can be damaged by any number of things
including
ESD.

--
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.


But is a CD laser diode any more susceptible to ESD damage than a bulk
standard red LED or a 1N4148 say, in otherwise the same poor handling
circumstances?

So what likely went wrong with the laser? Old and new both measure about
0.65V DVM diode test but powered in circuit the old one was dropping 4.6V
over the diode and the replacement, working one, about 1.8V across the
laser.

"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:

First time for years (no salvaged one on hand) I replaced old with new
but
had forgotten about those antistatic shorting links, wasting time trying
to
find the short. Nothing on the box about the shorting link, only graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone to
static
damage?

Yes, the laser diode. There's generally very little circuitry between the
cable and laser diode and it can be damaged by any number of things
including
ESD.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

But is a CD laser diode any more susceptible to ESD damage than a bulk
standard red LED or a 1N4148 say, in otherwise the same poor handling
circumstances?

YES! A 1 ns current spike with a peak just above the laser diode's maximum
rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V cap
across a laser diode will destroy it. Etc., etc. Look at it the wrong
way.....

--
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.

On Thu, 23 Dec 2010 12:22:35 -0000, "N_Cook" wrote:

So what likely went wrong with the laser? Old and new both measure about
0.65V DVM diode test but powered in circuit the old one was dropping 4.6V
over the diode and the replacement, working one, about 1.8V across the
laser.


The old laser has ceased to lase, though damaged ones may still emit light
(IR). You old one apparently does not even emit light, thus the high
terminal voltage from the (IR) output regulation circuitry.

"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:

First time for years (no salvaged one on hand) I replaced old with
new
but
had forgotten about those antistatic shorting links, wasting time
trying
to
find the short. Nothing on the box about the shorting link, only
graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone to
static
damage?

Yes, the laser diode. There's generally very little circuitry between
the
cable and laser diode and it can be damaged by any number of things
including
ESD.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

But is a CD laser diode any more susceptible to ESD damage than a bulk
standard red LED or a 1N4148 say, in otherwise the same poor handling
circumstances?

YES! A 1 ns current spike with a peak just above the laser diode's
maximum
rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V cap
across a laser diode will destroy it. Etc., etc. Look at it the wrong
way.....

--
sam

All absolutely agreed. However, to answer one of Mr Cook's earlier
questions, given that they do have this extreme static sensitivity,
curiously, the answer is no - not all replacement optical blocks *do* have
the laser diode shorted for transit. As well as shorting blobs on the pcb,
other methods of shorting that may be found are a thin metal plate in the
ZIF connector that some have, and a tiny switch that I have seen fitted to
some DVD optical blocks. And of course the solder blobs on the flexiprint
tail rather than on the board, and the 'snip-off' piece of flexiprint (two
varieties) to be found on some Panasonic lasers.

Arfa

"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:

First time for years (no salvaged one on hand) I replaced old with
new
but
had forgotten about those antistatic shorting links, wasting time
trying
to
find the short. Nothing on the box about the shorting link, only
graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone to
static
damage?

Yes, the laser diode. There's generally very little circuitry between
the
cable and laser diode and it can be damaged by any number of things
including
ESD.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

But is a CD laser diode any more susceptible to ESD damage than a bulk
standard red LED or a 1N4148 say, in otherwise the same poor handling
circumstances?

YES! A 1 ns current spike with a peak just above the laser diode's
maximum
rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V cap
across a laser diode will destroy it. Etc., etc. Look at it the wrong
way.....

--
sam

All absolutely agreed. However, to answer one of Mr Cook's earlier
questions, given that they do have this extreme static sensitivity,
curiously, the answer is no - not all replacement optical blocks *do* have
the laser diode shorted for transit. As well as shorting blobs on the pcb,
other methods of shorting that may be found are a thin metal plate in the
ZIF connector that some have, and a tiny switch that I have seen fitted to
some DVD optical blocks. And of course the solder blobs on the flexiprint
tail rather than on the board, and the 'snip-off' piece of flexiprint (two
varieties) to be found on some Panasonic lasers.

Arfa


And some models like the KSS-240 have the power limiting circuit built in;
no shorting required.

Mark Z.

"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:

First time for years (no salvaged one on hand) I replaced old with
new
but
had forgotten about those antistatic shorting links, wasting time
trying
to
find the short. Nothing on the box about the shorting link, only
graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone
to
static
damage?

Yes, the laser diode. There's generally very little circuitry
between the
cable and laser diode and it can be damaged by any number of things
including
ESD.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

But is a CD laser diode any more susceptible to ESD damage than a bulk
standard red LED or a 1N4148 say, in otherwise the same poor handling
circumstances?

YES! A 1 ns current spike with a peak just above the laser diode's
maximum
rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V
cap
across a laser diode will destroy it. Etc., etc. Look at it the wrong
way.....

--
sam

All absolutely agreed. However, to answer one of Mr Cook's earlier
questions, given that they do have this extreme static sensitivity,
curiously, the answer is no - not all replacement optical blocks *do*
have the laser diode shorted for transit. As well as shorting blobs on
the pcb, other methods of shorting that may be found are a thin metal
plate in the ZIF connector that some have, and a tiny switch that I have
seen fitted to some DVD optical blocks. And of course the solder blobs on
the flexiprint tail rather than on the board, and the 'snip-off' piece of
flexiprint (two varieties) to be found on some Panasonic lasers.

Arfa


And some models like the KSS-240 have the power limiting circuit built in;
no shorting required.

Mark Z.

Yes indeed. And talking of 240's, have you had problems with some players
which use one - particularly Sonys themselves - just not liking the generic
replacements, and suffering all sorts of playability problems after
replacement ? Whenever I had a Sony in that needed a 240, I always used to
quote for a genuine original part ordered from Sony, but it seems that they
are now no longer available from them. I have just picked one up for repair
from one of my feeder shops, and he has asked me to try a stock 240 in it,
but based on experience, I'm pretty sure that it's not going to provide
acceptable performance. I wonder why this should be, given that there
doesn't seem to be a problem with generic replacements in any other Sony
models, or problems using a generic 240 in any non-Sony players ?

Arfa

"Arfa Daily" wrote in message
...


"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:

First time for years (no salvaged one on hand) I replaced old with
new
but
had forgotten about those antistatic shorting links, wasting time
trying
to
find the short. Nothing on the box about the shorting link, only
graphic
showing use antistatic wrist strap for assembly
Do they all have these solder-across semicircle land pairs?
This one Sanyo SF-P101 has them , so do KSS213 and K SM213, all ?
Is there something in the laser assembly that is especially prone
to
static
damage?

Yes, the laser diode. There's generally very little circuitry
between the
cable and laser diode and it can be damaged by any number of things
including
ESD.

--
sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

But is a CD laser diode any more susceptible to ESD damage than a bulk
standard red LED or a 1N4148 say, in otherwise the same poor handling
circumstances?

YES! A 1 ns current spike with a peak just above the laser diode's
maximum
rating can destroy it. Accidentally connecting a charged 0.01 uF 5 V
cap
across a laser diode will destroy it. Etc., etc. Look at it the wrong
way.....

--
sam

All absolutely agreed. However, to answer one of Mr Cook's earlier
questions, given that they do have this extreme static sensitivity,
curiously, the answer is no - not all replacement optical blocks *do*
have the laser diode shorted for transit. As well as shorting blobs on
the pcb, other methods of shorting that may be found are a thin metal
plate in the ZIF connector that some have, and a tiny switch that I have
seen fitted to some DVD optical blocks. And of course the solder blobs
on the flexiprint tail rather than on the board, and the 'snip-off'
piece of flexiprint (two varieties) to be found on some Panasonic
lasers.

Arfa


And some models like the KSS-240 have the power limiting circuit built
in; no shorting required.

Mark Z.

Yes indeed. And talking of 240's, have you had problems with some players
which use one - particularly Sonys themselves - just not liking the
generic replacements, and suffering all sorts of playability problems
after replacement ? Whenever I had a Sony in that needed a 240, I always
used to quote for a genuine original part ordered from Sony, but it seems
that they are now no longer available from them. I have just picked one up
for repair from one of my feeder shops, and he has asked me to try a stock
240 in it, but based on experience, I'm pretty sure that it's not going to
provide acceptable performance. I wonder why this should be, given that
there doesn't seem to be a problem with generic replacements in any other
Sony models, or problems using a generic 240 in any non-Sony players ?

Arfa


Hey, Geoff.

Actually there's been so few replaced by me in recent years, I don't think
I've used a generic 240 yet. I've gotten "original Sony" pickups from a
reliable supplier, but none lately, so those "NOS" pickups may be gone.
I do believe that a lot of the "flaky KSS240" problems we experienced over
the years were actually bad flat wires. Had one a couple months back.
Of course I can see where a generic might be shipped unadjusted and that
could be disastrous. The are three adjustments on the 240 as you know, not
just the laser power adjustment. Kind of hard to adjust them while they are
playing!

Mark Z.

Mark Zacharias wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:





Hey, Geoff.

Actually there's been so few replaced by me in recent years, I don't think
I've used a generic 240 yet. I've gotten "original Sony" pickups from a
reliable supplier, but none lately, so those "NOS" pickups may be gone.
I do believe that a lot of the "flaky KSS240" problems we experienced over
the years were actually bad flat wires. Had one a couple months back.
Of course I can see where a generic might be shipped unadjusted and that
could be disastrous. The are three adjustments on the 240 as you know, not
just the laser power adjustment. Kind of hard to adjust them while they
are
playing!

Mark Z.



This generic Sanyo one , oriental script only, had the pot "set" at zero
ohms as well as zero ohms across the laser

"N_Cook" wrote in message
...
Mark Zacharias wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:





Hey, Geoff.

Actually there's been so few replaced by me in recent years, I don't
think
I've used a generic 240 yet. I've gotten "original Sony" pickups from a
reliable supplier, but none lately, so those "NOS" pickups may be gone.
I do believe that a lot of the "flaky KSS240" problems we experienced
over
the years were actually bad flat wires. Had one a couple months back.
Of course I can see where a generic might be shipped unadjusted and that
could be disastrous. The are three adjustments on the 240 as you know,
not
just the laser power adjustment. Kind of hard to adjust them while they
are
playing!

Mark Z.



This generic Sanyo one , oriental script only, had the pot "set" at zero
ohms as well as zero ohms across the laser


That seems very odd. I don't think I've ever seen that. So, when you'd
removed the solder blob short, did it still not work ? Or was the pot being
"set at zero ohms" equivalent to it running flat out ? Again, and odd
situation ... Did you reset it to some other value ? How ? Laser power
meter ?

Arfa

Arfa Daily wrote in message
...


"N_Cook" wrote in message
...
Mark Zacharias wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:





Hey, Geoff.

Actually there's been so few replaced by me in recent years, I don't
think
I've used a generic 240 yet. I've gotten "original Sony" pickups from a
reliable supplier, but none lately, so those "NOS" pickups may be gone.
I do believe that a lot of the "flaky KSS240" problems we experienced
over
the years were actually bad flat wires. Had one a couple months back.
Of course I can see where a generic might be shipped unadjusted and
that
could be disastrous. The are three adjustments on the 240 as you know,
not
just the laser power adjustment. Kind of hard to adjust them while they
are
playing!

Mark Z.



This generic Sanyo one , oriental script only, had the pot "set" at zero
ohms as well as zero ohms across the laser


That seems very odd. I don't think I've ever seen that. So, when you'd
removed the solder blob short, did it still not work ? Or was the pot
being
"set at zero ohms" equivalent to it running flat out ? Again, and odd
situation ... Did you reset it to some other value ? How ? Laser power
meter ?

Arfa


Pedants and purist look away now








I set the pot to the value of the original one and worked without hickup.
Then used the following , adjusting pot, which turned out to be centred as
far as I could tell by this method, to optimal as first set.

For checking error correction /immunity to errors.
An out of favour audio CD but otherwise in perfect playable condition.
With an assortment of potentiometer back nuts and washers ,small motor
pulleys find a combination that will "fill up" the hole in the centre of the
CD leaving
just a small hole at the very centre> With a set of "geometry" dividers
put one point
in this hole and lightly scratch a gouge about halfway along a radius of the
CD and about 1/4 of the circumference at that radius. Remove the washers
etc and play on a known good player.
Repeat the groove cutting deeper/wider/number of nearby grooves until one
track
or part of that track fails to play.
Make a note of the track number and start seconds and finish seconds
into the track/sections of track/s that are absent.
For your own machine every now and then (months) play and note the numbers
to note
long term drift. More absences/ longer absences over time indicates
deterioration in optics /correction . Use the same CD for checking in CD
repair of other machines and crude adjusting of optical power etc.

"N_Cook" wrote in message
...
Arfa Daily wrote in message
...


"N_Cook" wrote in message
...
Mark Zacharias wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:





Hey, Geoff.

Actually there's been so few replaced by me in recent years, I don't
think
I've used a generic 240 yet. I've gotten "original Sony" pickups from
a
reliable supplier, but none lately, so those "NOS" pickups may be
gone.
I do believe that a lot of the "flaky KSS240" problems we experienced
over
the years were actually bad flat wires. Had one a couple months back.
Of course I can see where a generic might be shipped unadjusted and
that
could be disastrous. The are three adjustments on the 240 as you know,
not
just the laser power adjustment. Kind of hard to adjust them while
they
are
playing!

Mark Z.



This generic Sanyo one , oriental script only, had the pot "set" at
zero
ohms as well as zero ohms across the laser


That seems very odd. I don't think I've ever seen that. So, when you'd
removed the solder blob short, did it still not work ? Or was the pot
being
"set at zero ohms" equivalent to it running flat out ? Again, and odd
situation ... Did you reset it to some other value ? How ? Laser power
meter ?

Arfa


Pedants and purist look away now








I set the pot to the value of the original one and worked without hickup.
Then used the following , adjusting pot, which turned out to be centred as
far as I could tell by this method, to optimal as first set.

For checking error correction /immunity to errors.
An out of favour audio CD but otherwise in perfect playable condition.
With an assortment of potentiometer back nuts and washers ,small motor
pulleys find a combination that will "fill up" the hole in the centre of
the
CD leaving
just a small hole at the very centre> With a set of "geometry" dividers
put one point
in this hole and lightly scratch a gouge about halfway along a radius of
the
CD and about 1/4 of the circumference at that radius. Remove the washers
etc and play on a known good player.
Repeat the groove cutting deeper/wider/number of nearby grooves until one
track
or part of that track fails to play.
Make a note of the track number and start seconds and finish seconds
into the track/sections of track/s that are absent.
For your own machine every now and then (months) play and note the numbers
to note
long term drift. More absences/ longer absences over time indicates
deterioration in optics /correction . Use the same CD for checking in CD
repair of other machines and crude adjusting of optical power etc.



That's quite novel. I actually have a test CD from Panasonic, that has
similar linear defects literally 'burnt' into the play layer. There is also
another one I have, which has a piece of PCB masking tape (the old black
lines used when making your own pcbs) right across a radius. This allows you
to look at the recovery times of the servos at various rotational speeds.

I'm still a bit puzzled though as to why this 'new out of the box' laser,
came from the manufacturer in an apparently unadjusted condition. I don't
think that I have ever seen this. Most are factory set and sealed. There are
a few notable exceptions, such as some Pioneer lasers where setting the
output level is an integral part of the service and set-up procedure, but
even then, they are set 'ball park' and seldom require much adjustment to
achieve the 'standard' 1v p-p eye pattern

Arfa

Arfa Daily wrote in message
...


"N_Cook" wrote in message
...
Arfa Daily wrote in message
...


"N_Cook" wrote in message
...
Mark Zacharias wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:





Hey, Geoff.

Actually there's been so few replaced by me in recent years, I don't
think
I've used a generic 240 yet. I've gotten "original Sony" pickups
from
a
reliable supplier, but none lately, so those "NOS" pickups may be
gone.
I do believe that a lot of the "flaky KSS240" problems we
experienced
over
the years were actually bad flat wires. Had one a couple months
back.
Of course I can see where a generic might be shipped unadjusted and
that
could be disastrous. The are three adjustments on the 240 as you
know,
not
just the laser power adjustment. Kind of hard to adjust them while
they
are
playing!

Mark Z.



This generic Sanyo one , oriental script only, had the pot "set" at
zero
ohms as well as zero ohms across the laser


That seems very odd. I don't think I've ever seen that. So, when you'd
removed the solder blob short, did it still not work ? Or was the pot
being
"set at zero ohms" equivalent to it running flat out ? Again, and odd
situation ... Did you reset it to some other value ? How ? Laser power
meter ?

Arfa


Pedants and purist look away now








I set the pot to the value of the original one and worked without
hickup.
Then used the following , adjusting pot, which turned out to be centred
as
far as I could tell by this method, to optimal as first set.

For checking error correction /immunity to errors.
An out of favour audio CD but otherwise in perfect playable condition.
With an assortment of potentiometer back nuts and washers ,small motor
pulleys find a combination that will "fill up" the hole in the centre of
the
CD leaving
just a small hole at the very centre> With a set of "geometry"
dividers
put one point
in this hole and lightly scratch a gouge about halfway along a radius of
the
CD and about 1/4 of the circumference at that radius. Remove the
washers
etc and play on a known good player.
Repeat the groove cutting deeper/wider/number of nearby grooves until
one
track
or part of that track fails to play.
Make a note of the track number and start seconds and finish seconds
into the track/sections of track/s that are absent.
For your own machine every now and then (months) play and note the
numbers
to note
long term drift. More absences/ longer absences over time indicates
deterioration in optics /correction . Use the same CD for checking in CD
repair of other machines and crude adjusting of optical power etc.



That's quite novel. I actually have a test CD from Panasonic, that has
similar linear defects literally 'burnt' into the play layer. There is
also
another one I have, which has a piece of PCB masking tape (the old black
lines used when making your own pcbs) right across a radius. This allows
you
to look at the recovery times of the servos at various rotational speeds.

I'm still a bit puzzled though as to why this 'new out of the box' laser,
came from the manufacturer in an apparently unadjusted condition. I don't
think that I have ever seen this. Most are factory set and sealed. There
are
a few notable exceptions, such as some Pioneer lasers where setting the
output level is an integral part of the service and set-up procedure, but
even then, they are set 'ball park' and seldom require much adjustment to
achieve the 'standard' 1v p-p eye pattern

Arfa


On most occassions I've had a salvaged one , so I automatically change the
pot to whatever the setting was for the current repair as an initial set. So
naturally noticed this new one was at the end of track, 0 ohm. Plugged in
forgetting about the shorting links as I'm not accustomed to seeing them. No
magic smoke, just absolutely no dull red glow in a dark room.

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...
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...


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...
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eb.com...
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"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:





Hey, Geoff.

Actually there's been so few replaced by me in recent years, I
don't
think
I've used a generic 240 yet. I've gotten "original Sony" pickups
from
a
reliable supplier, but none lately, so those "NOS" pickups may be
gone.
I do believe that a lot of the "flaky KSS240" problems we
experienced
over
the years were actually bad flat wires. Had one a couple months
back.
Of course I can see where a generic might be shipped unadjusted and
that
could be disastrous. The are three adjustments on the 240 as you
know,
not
just the laser power adjustment. Kind of hard to adjust them while
they
are
playing!

Mark Z.



This generic Sanyo one , oriental script only, had the pot "set" at
zero
ohms as well as zero ohms across the laser


That seems very odd. I don't think I've ever seen that. So, when you'd
removed the solder blob short, did it still not work ? Or was the pot
being
"set at zero ohms" equivalent to it running flat out ? Again, and odd
situation ... Did you reset it to some other value ? How ? Laser
power
meter ?

Arfa


Pedants and purist look away now








I set the pot to the value of the original one and worked without
hickup.
Then used the following , adjusting pot, which turned out to be centred
as
far as I could tell by this method, to optimal as first set.

For checking error correction /immunity to errors.
An out of favour audio CD but otherwise in perfect playable condition.
With an assortment of potentiometer back nuts and washers ,small motor
pulleys find a combination that will "fill up" the hole in the centre
of
the
CD leaving
just a small hole at the very centre> With a set of "geometry"
dividers
put one point
in this hole and lightly scratch a gouge about halfway along a radius
of
the
CD and about 1/4 of the circumference at that radius. Remove the
washers
etc and play on a known good player.
Repeat the groove cutting deeper/wider/number of nearby grooves until
one
track
or part of that track fails to play.
Make a note of the track number and start seconds and finish seconds
into the track/sections of track/s that are absent.
For your own machine every now and then (months) play and note the
numbers
to note
long term drift. More absences/ longer absences over time indicates
deterioration in optics /correction . Use the same CD for checking in
CD
repair of other machines and crude adjusting of optical power etc.



That's quite novel. I actually have a test CD from Panasonic, that has
similar linear defects literally 'burnt' into the play layer. There is
also
another one I have, which has a piece of PCB masking tape (the old black
lines used when making your own pcbs) right across a radius. This allows
you
to look at the recovery times of the servos at various rotational speeds.

I'm still a bit puzzled though as to why this 'new out of the box' laser,
came from the manufacturer in an apparently unadjusted condition. I don't
think that I have ever seen this. Most are factory set and sealed. There
are
a few notable exceptions, such as some Pioneer lasers where setting the
output level is an integral part of the service and set-up procedure, but
even then, they are set 'ball park' and seldom require much adjustment to
achieve the 'standard' 1v p-p eye pattern

Arfa


On most occassions I've had a salvaged one , so I automatically change the
pot to whatever the setting was for the current repair as an initial set.
So
naturally noticed this new one was at the end of track, 0 ohm. Plugged in
forgetting about the shorting links as I'm not accustomed to seeing them.
No
magic smoke, just absolutely no dull red glow in a dark room.


Hmmmm. If you've got away with that to date, I feel that you have been
lucky. Normally, the optical block is factory adjusted to give the correct
output power for the laser diode fitted. I understand that the output power
of laser diodes for a given bias, is quite variable, hence the need for the
adjustment. These diodes are also very sensitive to over-drive, and the
smallest amount can damage them in short order, which is why just turning up
a worn one is seldom successful for more than a few weeks, before total
failure. If swapping optical blocks from scrappers to repairs - which is not
in my opinion a very worthwhile practice, given the low price of most
replacement lasers anyway - I would feel inclined to leave the pot set where
the factory put it to suit the particular diode fitted to that particular
block.

Arfa

Arfa Daily wrote:


"N_Cook" wrote in message
...
Arfa Daily wrote in message
...


"N_Cook" wrote in message
...
Mark Zacharias wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"Samuel M. Goldwasser" wrote in message
...
"N_Cook" writes:

Samuel M. Goldwasser wrote in message
...
"N_Cook" writes:





Hey, Geoff.

Actually there's been so few replaced by me in recent years, I don't
think
I've used a generic 240 yet. I've gotten "original Sony" pickups from
a
reliable supplier, but none lately, so those "NOS" pickups may be
gone.
I do believe that a lot of the "flaky KSS240" problems we experienced
over
the years were actually bad flat wires. Had one a couple months back.
Of course I can see where a generic might be shipped unadjusted and
that
could be disastrous. The are three adjustments on the 240 as you know,
not
just the laser power adjustment. Kind of hard to adjust them while
they
are
playing!

Mark Z.



This generic Sanyo one , oriental script only, had the pot "set" at
zero
ohms as well as zero ohms across the laser


That seems very odd. I don't think I've ever seen that. So, when you'd
removed the solder blob short, did it still not work ? Or was the pot
being
"set at zero ohms" equivalent to it running flat out ? Again, and odd
situation ... Did you reset it to some other value ? How ? Laser power
meter ?

Arfa


Pedants and purist look away now








I set the pot to the value of the original one and worked without hickup.
Then used the following , adjusting pot, which turned out to be centred as
far as I could tell by this method, to optimal as first set.

For checking error correction /immunity to errors.
An out of favour audio CD but otherwise in perfect playable condition.
With an assortment of potentiometer back nuts and washers ,small motor
pulleys find a combination that will "fill up" the hole in the centre of
the
CD leaving
just a small hole at the very centre> With a set of "geometry" dividers
put one point
in this hole and lightly scratch a gouge about halfway along a radius of
the
CD and about 1/4 of the circumference at that radius. Remove the washers
etc and play on a known good player.
Repeat the groove cutting deeper/wider/number of nearby grooves until one
track
or part of that track fails to play.
Make a note of the track number and start seconds and finish seconds
into the track/sections of track/s that are absent.
For your own machine every now and then (months) play and note the numbers
to note
long term drift. More absences/ longer absences over time indicates
deterioration in optics /correction . Use the same CD for checking in CD
repair of other machines and crude adjusting of optical power etc.



That's quite novel. I actually have a test CD from Panasonic, that has
similar linear defects literally 'burnt' into the play layer. There is also
another one I have, which has a piece of PCB masking tape (the old black
lines used when making your own pcbs) right across a radius. This allows you
to look at the recovery times of the servos at various rotational speeds.

a plain audio CD with black electrical tape "spokes" across the disc was
how we tested CD players for being faulty. I don't recall how wide the
strips were, but probably 1/8"th inch or so. It was obviously homemade
like a VHS cassette shell with the windows popped out for testing takeup
reel torque.