Fixing "Zig-Zag Banding Noise" in Nikon Super Coolscan scanners.

This problem has been discovered by Graeme Hardie at LincolnScan in UK (https://lincolnscan.co.uk/Coolscan.html).

Graeme investigated it and came up with a solution, I am just copying his report here.

The problem presents itself as zig-zag patterns in the scans, particularly in the dark areas, as can be seen in the left image below. In all coolscan models this is caused by a deteriorated small electrolytic capacitor (10uF 16V) associated with the analog-digital converter (ADC). Replacing that capacitor with a multi-layer ceramic capacitor (also 10uF 16V, size code 1210) fixes the problem.

Here is a link to Graeme's original post:

https://www.facebook.com/groups/1514948298527146/posts/5539748439380425

Here is a text from his post:

"I’ve started seeing this increasingly in LS-8000s only. Recently I had a particularly bad example which caused me to investigate further. The fault moved with the mainboard and was visually an analogue phenomenon which pointed to the analogue-digital converter (ADC) circuit. I found that both the small electrolytic 10uF capacitors associated with the ADC had deteriorated badly (very high ESR). The scanner had spent time in India so probably a warm climate had accelerated the capacitor aging. Smaller electrolytics are the first to suffer.
I replaced the two 10uF 16V capacitors with ceramic types (MLCC) since I didn’t have electrolytics to hand (these perform and age better anyway). The zig-zag pattern disappeared.
It is surprising that LS-4000s of the same age are not similarly affected but the ones I have looked at have 10uF capacitors from a different manufacturer which haven’t deteriorated so badly (yet). Having said that, I have seen the banding very faintly in a 4000 and this also disappeared after the capacitor change."

Below are two zoomed-in crops of scans performed using Nikon LS-8000. The one the left has noticeable noise that Graeme called "Zig-Zag Banding Noise". Replacing the capacitor next to C213 on the LS-8000 motherboard fixed the problem (right image).

Below is a page from Graeme's article on the issue:

Finally, here is the list of the capacitors in different coolscan models that need to be replaced to fix zig-zag banding problem, composed by Graeme Hardie:

The recommended replacement capacitor is MLCC (multi-layer ceramic capacitor) 1210 type.

Here is an example TDK CNC5L1X7R1C106K160AE.

Here are the photos of the motherboards with locations of the capacitor to replace indicated by yellow circles:

LS-4000 (C196, C200, C202, and C212 on the motherboard)

LS-8000 (C250 and unmarked capacitor next to C213 on the motherboard)

LS-5000 (C156, C171, C175 on the motherboard)

There are two versions of LS-5000 motherboard. Shown above is the version with the part number 1S015-145 - with the original capacitors.

Shown below is the version with the part number PT170054-1001 - with the replaced capacitors. Capacitor ID's are the same (C156, C171, and C175), but the locations are slightly different.

LS-9000 (C18 on the CCD board)