Somewhat OT, but ... (Slide scanners)

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I have a Minolta Scan Dual IV slide scanner that seem to have died  
recently. 'Seems' because it was working when I left it for my sister to  
use at Xmas, but she says that its now apparently starting up correctly  
(and I heard it making the expected noises over the phone), but it  
refuses to accept a filled slide holder for scanning. She's 100 miles  
away, so I haven't popped in to take a look myself so far. We're using  
VueScan to drive it, which worked very well with it in the past. I have  
its manual which, as usual, is useless for trouble shooting.

So, can any of you recommend someone who can check and possibly fix the  
scanner?  

I'm asking here because this is a generally knowledgeable group on all  
sorts of computer-related topics.  


--  
Martin    | martin at
Gregorie  | gregorie dot org

Re: Somewhat OT, but ... (Slide scanners)
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I have on of those scanners and it has developed a fault with a collar that  
connects the stepper motor to the mechanism that advances the sensor. The  
collar has split so the push-fit onto the motor shaft sometimes slips.

I fixed it by putting tape round the collar to hold it to the correct size  
and then wrapped a bit of tap round the motor shaft to make it slightly  
larger. Together, these make sure that when the motor turns a few steps, the  
advance mechanism moves the correct amount.  


Re: Somewhat OT, but ... (Slide scanners)
On Wed, 09 Jan 2019 15:13:20 +0000, NY wrote:

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That's clear, but I'm uncertain if mine has the same problem, so here's  
the sequence I followed and where I think it fails:

1) I hit the ON switch. The green light flashes a bit and then stays on

2) Then, when Vuescan is launched I hear the scanned run a stepper motor
   fairly fast three times as Vuecan gets synced with it

3) When I put the slide holder in, I push it in about 20mm against some
   resistance until I feel it 'click', at which point the stepper pulls
   it in past the first slide, running a lot slower than it did during
   initialisation.

4) Then hitting scan does the business, producing a good quality image
   which is then saved as a JPG. This is the latest version of  
   Vuescan and differs from the copy I last used back in 2011, when
   scanning was a three stage process: scan in a low resolution preview,
   use it to set framing etc, do the high resolution scan and only then  
   save the image.

From what my sister said the scanner no longer grabs the slide holder  
when it is pushed in (step 3). I was on the phone during the last attempt  
and clearly heard the triple set of stepper runs during initialisation,  
but did not hear anything when the slide holder was pushed in.

I realise its probably a long time since you had a problem with your  
scanner, but how does this more detailed account compare with your  
experience?


--  
Martin    | martin at
Gregorie  | gregorie dot org

Re: Somewhat OT, but ... (Slide scanners)

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Sadly I think it's different. In my case the slide holder was being sucked  
into the machine OK, but then the very slow pixel-by-pixel advance during a  
scan was slipping. I wonder if two different motors are used for the coarse  
feed for loading the slide holder and the fine feed during scanning.

I think I'm correct in this: it was a year or so ago when I had the problem.  
I'll see if I can find the scanner and its PSU (it's always the PSU that  
goes missing with appliances!) and check my memory of the symptoms that I  
had.


I remember that my fix with tape round the motor spindle affected the aspect  
ratio slightly, so I had to punch a hole in a bit of film leader with a hole  
punch and measure the exact pixel dimensions on two axes, and apply a  
correction to all scans. If only Minolta were still in business I would get  
a new plastic collar to replace the one that's split.  


Re: Somewhat OT, but ... (Slide scanners)
On Wed, 09 Jan 2019 18:08:02 +0000, NY wrote:

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Good point: mine initially had an overheating problem which meant it  
would need rebooting toward the end of the third box of slides in a  
scanning session so I had it apart to see if I could fit a fan.

I don't remember how many steppers I saw in it.

FWIW I didn't fit the fan, mainly because it would have involved chopping  
a fan-sized hole in the case and, probably, adding a baffled outlet  
passage on the outside to stop light leaking in and degrading the scanned  
image's contrast ratio.


--  
Martin    | martin at
Gregorie  | gregorie dot org

Re: Somewhat OT, but ... (Slide scanners)
On 09/01/2019 18:08, NY wrote:
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Even more OT. I never throw away Wallwart PSUs etc. unless they are  
faulty. This is why I have collected two boxes of PSUs in the last 35  
years since moving into my own home. At the last count there were over  
70 of the buggers! The adoption of USB mini A or micro B based chargers  
means very few have been added to the collection in the last few years.

Re: Somewhat OT, but ... (Slide scanners)
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Ah! Many apologies. I've just checked my scanner and it's a Scan Elite II,  
not a Scan Dual IV. My experiences and remedies may well not apply to your  
model.

It looks as if on my model there is only one motor (apart from the focus  
motor) so evidently this must both load the slide holder and feed it at low  
speed for scanning.

Here are my instructions, on the off-chance that they are relevant to your  
model.

1. Remove single screw on reverse (by USB and power sockets).

2. Remove four screws on base beside rubber feet, but not two on underside  
of front panel.

3. Unscrew the two screws on the metal plate in  
https://i.postimg.cc/nVPfvGdh/Img-1750-small.jpg

4. Remove the two ribbon cables from their sockets  
https://i.postimg.cc/8cj827CG/Img-1742-small.jpg(wiggle and pull out; maybe  
label them first to make sure they go back in the correct sockets)

5.
https://i.postimg.cc/TYKGS4yb/Img-1747-small.jpgis the collar that  
connects at the left hand end to the stepper motor and the right hand end to  
the feeder advance for loading the slide holder and for moving the slide  
past the sensor

6. If the motor is slipping on the collar, unscrew the motor  
https://i.postimg.cc/d3pMwJ7y/Img-1749-small.jpgand wiggle to remove its  
spindle from the collar (push fit, although I wonder if there are also Allen  
key grub screws on the collar)

7. Wrap a bit of tape round the motor spindle and then refit the motor -  
hopefully there is now a tight fit between the spindle and the collar. Looks  
as if I didn't try binding the outside of the collar to repair the split -  
I'd remembered that bit wrongly.

8. Refit everything by following Steps 6-1 in that order.


This may all be totally irrelevant to your scanner, but it may help you...  


Re: Somewhat OT, but ... (Slide scanners)
On Wed, 09 Jan 2019 19:08:14 +0000, NY wrote:

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Thanks for that.  

Repairwise, I've an aeromodelling background, so if I'd had your problem  
I probably would have run a drill through the collar and shaft and put a  
small machine screw and Nylock nut through to lock them together. An 8 or  
10BA screw would do the job.  


--  
Martin    | martin at
Gregorie  | gregorie dot org

Re: Somewhat OT, but ... (Slide scanners)
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I did wonder about that, but the shaft is only about 2 mm diameter so it  
would be difficult to drill through it without cutting it in half. Grub  
screws to bite onto the shaft should be a good way of fastening collar to  
shaft in that case.

I did wonder about trying to file a flat onto the shaft for a screw in the  
collar to get a better purchase on.

I'm suspicious of any precision mechanical fittings that are plastic rather  
than metal. Plastic (the collar was probably nylon) is too inclined to crack  
under load or as it gets old.

Still, my admittedly bodged repairs was good enough to scan the photos of my  
parents' wedding in time for their 50th wedding anniversary :-)  Getting  
good scans from 50-year-old slides, some of which had faded and others of  
which were underexposed, was another matter. Slide film was so f-ing slow in  
the early 60s that even in good daylight, camera shake was a problem with  
some of them. Probably Kodachrome 25 (not even 64), and certainly not  
Ektachrome 200 or 400 :-)

As a matter of interest, have you had any success scanning negatives as  
opposed to slides? I find I cannot get natural-looking colours. They all  
look rather flat and with garish colours, like the coloured "plates"  
illustrations that you got in 1930s books. And dark objects against a light  
sky (a light object against a dark background on the neg) tend to suffer  
from bloom - the light diffuses sideways and giving a halo around the  
object. Having said that, there's a *lot* more shadow and highlight detail  
that a scan of a negative can reveal, compared with a scan of a print from a  
high street shop.

Minolta's software gave better results than VueScan, but it won't  
install/run on Win 7, only older version of Windows. VueScan has lots of  
presets but none which properly match the edge-markings on the film - mostly  
fairly standard Kodacolor print film, so nothing unusual.

Scans of B&W neg film are fine, though I find I get better results scanning  
either as a positive and reversing or else scanning as colour neg and then  
reducing to B&W. Does VueScan have presets for Ilford FP4 and HP5? I got  
fantastic results with the Ilford B&W film that uses colour chemistry,  
despite rather dense negatives (overdeveloped?) - sharpness was probably  
limited more by the camera lens than the film grain. I got less noticeable  
grain from that film at 400 ASA than for FP4 at 100 ASA.  


Re: Somewhat OT, but ... (Slide scanners)
On Wed, 09 Jan 2019 19:53:28 +0000, NY wrote:

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I didn't realise it was that thin - thought it would be more like 3-3.5mm!

I might still have drilled it, say at 0.7mm which is a push fit for  
22swg, and put a piece of piano wire or copper wire through with the ends  
bent over to stop it falling out.  
  
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The problem would be getting the enough threads on the collar - unless it  
was at least 2mm thick.
  
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Yes, I'm with you there.
  
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Tell me about it! the stuff I scanned was 1977/78 vintage Ektachrome -  
don't remember the ISO rating, but some of the sliders had a fine black  
speckling, v. noticeable on sky. Took me a long time to get that cleaned  
up with the GIMP but I think the effort was well worth it.  

Much of that slide collection, which covered an overland trip to India  
and back, was shot with a Leica IIIb through f3.5 Elmar 50mm and 35mm  
lenses and by waving a Weston Master IV meter at the scenery. The rest  
was shot on a 2nd hand Zenit with a cheap as chips East German f3.5 135  
lens that worked surprisingly well until about 18 months later when its  
iris disintegrated. Thats when it became obvious that the lenses were  
mounted in what looked suspiciously like Plaster of Paris(!).

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I've never tried, mainly because I've only ever used B&W roll film negs.

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I went with Vuescan mainly because I'd converted entirely to Linux about  
5 years earlier and at that stage WINE was still pretty much rubbish. I  
used Vuescan because it was about all I could find that could run on  
Linux and drive the Minolta.

Both WINE and Vuescan seem to have improved greatly since then.

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I haven't looked - sorry and don't currently have a runnable copy to  
check with. I was a bit surprised to find that I still have the 2011 copy  
installed but it won't run because at least one support library has moved  
on. I'll get hold of the latest version when the Minolta comes back and,  
hopefully, gets fixed.
  

--  
Martin    | martin at
Gregorie  | gregorie dot org

Re: Somewhat OT, but ... (Slide scanners)
On 09/01/2019 20:48, Martin Gregorie wrote:
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[Snip]

Please take this to email, as only you two have any interest in this off  
topic conversation.

---druck

Re: Somewhat OT, but ... (Slide scanners)

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Either that, or a more appropriate group, like sci.electronics.repair

Re: Somewhat OT, but ... (Slide scanners)
On Fri, 11 Jan 2019 14:41:35 -0800, Mike Paff wrote:

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Thanks for the hint. Subscribed.


--  
Martin    | martin at
Gregorie  | gregorie dot org

Re: Somewhat OT, but ... (Slide scanners)
On Wed, 09 Jan 2019 21:00:05 +0000, druck wrote:

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I may only be lurking but find the discussion interesting



--  
Good judgement comes from experience.  Experience comes from bad  
judgement.
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