I doubt something is wrong with your scanner. It's in line with what others are seeing and I don't think all the scanners have rotten by now. This site (Italian) has the best test of Minolta 5400 (I and II) ever made and also has Nikon 8000 test. If you check the samples and lift the shadows heavily you can see similar noise and scanners were relatively new at the time of test.
Actually, it's probably the most sensible solution. I've been looking at small led light source with hight CRI. Less heat, stable light, possibly less noise. It shouldn't be a difficult mod and it might bring additionnal benefits.
Is it the same issue or just standard thermal noise-derived patterns?
I am not sure I see the same thing. With multisampling their test images show almost no noise whereas the zigzag effect is even more pronounced with multisample enabled.
Also, and as stated before I've scanned the same image with the same scanner at different stages of its life, and the scans from 2015 do not show the same patterns. We are running circles here.
I wouldn't exclude the possibility that current problems are related to changes in operating systems and driver software.
Have only been able to quickly scan the article, but the review claims the issue happens with a combination of multisampling, grain dissolver and ICE?
I used none of the three above and found the band in my last example to show noise. Is it the same issue or just standard thermal noise-derived patterns?
Yeah, that would be an interesting approach for sure. I wouldn't stare myself bind on the CRI either. 90-95 is easy to get and will likely do fine. Keep in mind the sensor sees only spectral peaks of R, G and B anyway. As long as those are there in sufficient amounts, you'll be OK.
Do off the shelf LEDs typically go into IR spectrum enough to keep the ICE functionality of the scanner?
I also wonder if extreme densities of the scanned material are a factor here. Can people post a photograph of the negatives they're using? Does the problem only happen with very dense, perhaps overexposed slides?
Foma 200 in Fomadon LQN, and by mistake I ended up developing for a target gamma of .65. My standard target gamma is in the region of 0.55.
The problem insofar I've seen it is/was with slides, and the dark areas, so underexposed slides would be the worst. I don't see how this issue would conceivable play a big role with B&W let alone color negatives because those don't even come close in terms of density.
Yeah, so you're evaluating densities well below 2.0logD here. The problems exist with densities >3.0logD. That's a different world altogether.
Practical answer: no. It would involve basically a complete redesign of the electronics. Might as well replace the light source with something modern as well while you're at it. And perhaps have a look at the optics. Heck, why not dump the whole think and build a new one? That's what you'd end up doing.
One of the key bottlenecks is that it's unlikely to find a pin-compatible, instruction-compatible drop-in replacement for this ADC with better noise performance. So you'd be re-designing the PCB (or making some kind of Frankenstein piggy-back device) as well as implanting a new processor with newly made software into the thing at the very least. Which is a gargantuan task in itself.
No, not normal. Since they are vertical it can't be because of poor calibration. It could be transport problem, but I guess SF never gives you this problem...
After the ADC converter, can the scanner pick up noise?
The Coolscan 9000ED and 5000ED use the same AD9826 converter as the Minolta 5400.
This is the main board of the Minolta 5400, but the ADC chip is on the CCD board, next to the CCD:
Yes, but as @Anon Ymous this is exceedingly less likely and it'll look totally different from what's seen in the examples in this thread.After the ADC converter, can the scanner pick up noise?
Does anyone know what wavelengths the color filters on the CCD sensor?
The culprit in that case is C18.
Quite possible. But noise performance depends on more factors than the chip used, and those factors are generally of a much bigger influence. So it cannot be expected that these scanners will all have the same noise performance, nor the same failure modes over time.
Yes I see, but then the problem is concentrated on that component.Indeed, so the image shown isn't very relevant as it omits the critical part around the ADC and CCD. Photos of that area were posted earlier in this thread.
I don't expect this to be very critical if you're considering replacing the light source, since red, green and blue usually group around 450nm, 540nm and 650nm respectively, with a very generous allowance on either side of the peak (it's a pretty broad bell curve usually). The main question is at around which wavelength the IR acquisition is done, but I expect any normal 940nm IR LED would fit the bill just fine.
All I can see is that the problem is always with the aluminium electrolytic capacitors. But unfortunately I don't know much about electronics.Not that it really helps us in any case, but who knows...
then the problem is concentrated on that component.
I think the wide overlap RGB spectral distribution is a problem for colour separation.
Yes, that makes good sense. Note how C18 is part of the filter circuit around the CAPT and CAPB pins, which set a reference voltage. Any noise on a reference voltage will affect the output severely. Note that this section of the circuit in the Minolta 5400 is largely obscured by the connector between the CCD PCB and the mainboard
Or does anyone know the exact type of CCD sensor?
When you changed the capacitor in my scanner, was the capacitor in question related to the CAPT CAPB pins of the ADC?
I tried to a few pictures of the line sensor board. I found an electrolyte at the back of the PCB (C42) with a value of 10mf and 16v that matches the faulty electrolyte of the coolscans. Unfortunately, I can't really trace it back to pin 20 and 21 of the ADC. Maybe the board is dual layered and it is related ?
And here is a picture of the sensor board and the ADC without the huge connector. If someone is inspired, let us know.
Sony ILX739KA.
The author of this article once commented that Minolta 5400 and Canon FS4000US share the same CCD.
Hm, that's interesting; I'm pretty sure the replacement I did on your scanner was C22, but that's unpopulated on the photo you posted.
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