Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Adjusting scanner focus

Anyone here ever attempted (or better yet, succeeded at) adjusting the
focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old, still
works, still as noisy as ever. It works, but it's certainly not a great
scanner, and perhaps is doing the best it ever will do. But I'm not sure
it's in focus. Having stripped down scrapped scanners, I know there's a
focus adjustment, done at the factory and invariably set with some kind
of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I
suppose marking the current setting for return in case of problems, and
trial and error could work.

The other annoying thing about the scanner is that it has to be "warmed
up"; the first scan or two are always way too light and washed out. Is
this typical of CCDs of this vintage? I remember seeing this same
behavior with some low-res cameras my company used to use on a CD
printing system we made, to take snapshots of CDs in the printer tray;
our software took two or three shots, threw them away and then took one
for real.


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Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.
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Default Adjusting scanner focus


David Nebenzahl wrote:

Anyone here ever attempted (or better yet, succeeded at) adjusting the
focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old, still
works, still as noisy as ever. It works, but it's certainly not a great
scanner, and perhaps is doing the best it ever will do. But I'm not sure
it's in focus. Having stripped down scrapped scanners, I know there's a
focus adjustment, done at the factory and invariably set with some kind
of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I
suppose marking the current setting for return in case of problems, and
trial and error could work.

The other annoying thing about the scanner is that it has to be "warmed
up"; the first scan or two are always way too light and washed out. Is
this typical of CCDs of this vintage? I remember seeing this same
behavior with some low-res cameras my company used to use on a CD
printing system we made, to take snapshots of CDs in the printer tray;
our software took two or three shots, threw them away and then took one
for real.



The 'warmup' is the CCFL. The problem gets worse as they age. Some
change color before they fail, which screws up your white balance.


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Default Adjusting scanner focus

David Nebenzahl wrote in message
s.com...
Anyone here ever attempted (or better yet, succeeded at) adjusting the
focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old, still
works, still as noisy as ever. It works, but it's certainly not a great
scanner, and perhaps is doing the best it ever will do. But I'm not sure
it's in focus. Having stripped down scrapped scanners, I know there's a
focus adjustment, done at the factory and invariably set with some kind
of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I
suppose marking the current setting for return in case of problems, and
trial and error could work.

The other annoying thing about the scanner is that it has to be "warmed
up"; the first scan or two are always way too light and washed out. Is
this typical of CCDs of this vintage? I remember seeing this same
behavior with some low-res cameras my company used to use on a CD
printing system we made, to take snapshots of CDs in the printer tray;
our software took two or three shots, threw them away and then took one
for real.


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.



I would firstly try 3 test scans with a piece of paper, as normal, stuck
under the doc glass and placed over a piece of glass over the doc glass, to
see if there is a focussing difference


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Default Adjusting scanner focus

On Jan 3, 2:15*am, David Nebenzahl wrote:
Anyone here ever attempted (or better yet, succeeded at) adjusting the
focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old, still
works, still as noisy as ever. It works, but it's certainly not a great
scanner, and perhaps is doing the best it ever will do. But I'm not sure
it's in focus. Having stripped down scrapped scanners, I know there's a
focus adjustment, done at the factory and invariably set with some kind
of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I
suppose marking the current setting for return in case of problems, and
trial and error could work.

The other annoying thing about the scanner is that it has to be "warmed
up"; the first scan or two are always way too light and washed out. Is
this typical of CCDs of this vintage? I remember seeing this same
behavior with some low-res cameras my company used to use on a CD
printing system we made, to take snapshots of CDs in the printer tray;
our software took two or three shots, threw them away and then took one
for real.

--
Comment on quaint Usenet customs, from Usenet:

* *To me, the *plonk...* reminds me of the old man at the public hearing
* *who stands to make his point, then removes his hearing aid as a sign
* *that he is not going to hear any rebuttals.


I'm still trying to figure out why all of the scanners (four) I have
ever bought have permanently broken down within 2 or 3 days after I
buy them. Oy.

Ron
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Default Adjusting scanner focus

On 1/3/2011 3:14 AM N_Cook spake thus:

David Nebenzahl wrote in message
s.com...

Anyone here ever attempted (or better yet, succeeded at) adjusting
the focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old,
still works, still as noisy as ever. It works, but it's certainly
not a great scanner, and perhaps is doing the best it ever will do.
But I'm not sure it's in focus. Having stripped down scrapped
scanners, I know there's a focus adjustment, done at the factory
and invariably set with some kind of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I
suppose marking the current setting for return in case of problems,
and trial and error could work.


I would firstly try 3 test scans with a piece of paper, as normal, stuck
under the doc glass and placed over a piece of glass over the doc glass, to
see if there is a focussing difference


Why bother doing that? Of course there'll be a focusing difference: the
lens is wide-open, and therefore has a small depth of field, so moving
the subject by the thickness of a piece of glass will make a visible
difference.


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.


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Default Adjusting scanner focus

On Mon, 03 Jan 2011 13:45:42 -0800, David Nebenzahl wrote:
On 1/3/2011 3:14 AM N_Cook spake thus:
David Nebenzahl wrote

Anyone here ever attempted (or better yet, succeeded at) adjusting
the focus on an ordinary tabletop scanner?

I've got a cheapie (Microtek V6USL), now more than 10 years old,
still works, still as noisy as ever. It works, but it's certainly
not a great scanner, and perhaps is doing the best it ever will do.
But I'm not sure it's in focus. Having stripped down scrapped
scanners, I know there's a focus adjustment, done at the factory
and invariably set with some kind of paint or glue.

Just wondering if it would be worthwhile trying to adjust mine. I
suppose marking the current setting for return in case of problems,
and trial and error could work.


I would firstly try 3 test scans with a piece of paper, as normal, stuck
under the doc glass and placed over a piece of glass over the doc glass, to
see if there is a focussing difference


Why bother doing that? Of course there'll be a focusing difference: the
lens is wide-open, and therefore has a small depth of field, so moving
the subject by the thickness of a piece of glass will make a visible
difference.


Well, dooh: If one of the 'offset' images is much worse than the other,
he'll know which way the focus has shifted with respect to the top
surface of the scanner's glass. If there is no difference betwix the
two, then the problem is probably not focus, but rather dust, etc.

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