LS-4000ED Troubles

[Daniël Oosterhuis]

So I figured it would be worth a shot to see if anyone knows what is up with my Coolscan, and if/how/what to fix (it).

A while back, I, on a bit of a whim, bought a broken Coolscan LS-4000ED. It was cheap enough that I thought it'd be worth the risk, and from the way the seller described the issues I just assumed he meant the image had lines in it due to the mirror being dirty. He sold it with an SA-21 roll film adapter that was "broken". It had some broken plastic on the corner as shown in the advertisement pictures. With that, I figured as long as I keep it in a sealed plastic tub, it shouldn't get too dusty inside, so it'd be fine.

Once I got the bundle, the scanner would fail at the POST (Power On Self Test), really early on with the SA-21 adapter connected, before it would flash the backlight in RGB colors to check if it was properly working, as the POST should do. The POST would succeed without the adapter, but the adapter wouldn't be detected if I plugged it in afterwards. I found out the seller meant the SA-21 didn't work, but he was rather vague on if he tested it with other equipment or just this scanner, which I still do not know.

After a while, I got an MA-21 slide adapter for slides. Now, I currently suck at shooting slide, and to double down on that, the first time I went out shooting it, I relied on the lightmeter in the camera which turned out to be way too irreliable and my shots for the most part ended up overblown and horrid. Oh well, I'm a n00b, so I guess I'll just have to practice a bit more with the more forgiving negative film, which so far is going decent.

Anyways, I took one of the rather terrible slides, and tried it out. The scanner now did turn on, and Nikon Scan 4 on the PowerMac (I collect older Macs, which also means I have period correct hardware to test it with) said it was ready to go. I had already cleaned the mirror at this point, so I assumed we should get a fairly good image.

Again, I shouldn't have assumed the seller was making sense, as with lines in the image, he meant black lines. And actually, most of the scanned image being pitch black. One section of the image would scan properly each and everytime, but the rest would be pitch black with occassional lines of either the image, or random colors. I have just taken two samples, showing that the patch of film it scans fine (again, the slide does look that terrible in real life) is as it should, but the rest is just unusable. The first has no Digital ICE, the second does. This shows that on the patch of film that does scan right, DICE does make a difference.

This puzzles me. At first, when it didn't POST with the SA-21, I thought that maybe the power supply was going bad. After all, the SA-21 has motors and circuitry that pull extra power that the PSU, in all of its failing health, would fail to supply, which made sense given it would succeed the POST without the adapter. However, the randomness of the artifacting and the fact that one specific patch of film always seems to scan fine, don't really add up. Does the scanner consume less power when it's scanning that specific spot? Is there a bad connection somewhere that somehow fixes itself only in that specific spot?

That's why I'm hoping someone might have had this, or something similar, happen to their Coolscan, and knows what went wrong with it and how it was/could be fixed. I have basic soldering skills, and am willing to give it a shot as I have nothing to lose. I'm getting a hot air soldering station soon as well, for my other vintage computer hobby, which I could use to do SMD soldering, should a still-obtainable component on the motherboard have failed, given that uses SMD components compared to the through-hole components on the power supply board. Any ideas or tips are greatly appreciated.

 

[Eric Rose]

Wow, good luck with your adventures! Please keep us posted. I have two dead Nikon scanners that should have been sent to the trash heap ages ago. When they work they work well, but when they don't , well ,,,,,,,

 

[Kino]

It looks like the cable between the line array sensor and the main board might have broken connections that only make intermittent contact.

You might try looking over the data connection cable between the scanner head and the main motherboard to see if it can be replaced.

NOTE: be careful! Looks like it uses one of those god-awful ribbon cables that are plastic with oxide traces. They can be delicate!

Never having had a Nikon Coolscan, I can only speculate, but the total lack of information in some areas, and only one color (CYMK) per vertical stripe indicates this to me.

 

[Les Sarile]

At first, when it didn't POST with the SA-21, I thought that maybe the power supply was going bad.

From what I know about >30 years of electronics, power supply is always the first thing to check. Even more so when things work erratically. I anticipate it is also the "simplest" portion of the system. Have you looked at that yet?

I have two dead Nikon scanners that should have been sent to the trash heap ages ago.

Which models are they?

 

[Patrick Robert James]

I am not an expert but I would say the ribbon cable is the logical problem. Check it for cracks.

 

[Daniël Oosterhuis]

Thanks for all the replies so far. The ribbon cable sounds plausible, it could be pushed just right in place when it's doing the patch of film it scans properly. But it wouldn't explain the SA-21 failure, or it would mean the SA-21 is a whole other problem entirely.

As for the power supply, I've taken a look at it, but Nikon in their infinite wisdom decided to have a heatsink soldered directly to the board that overhangs several components, including some capacitors. Getting those out for testing is going to be a bit of a pain in the rear, so I might wait until I buy the hot air gun to be able to properly remove the heatsink entirely while inspecting it, as I don't think my cheapo Hakko-knock off soldering station iron has the thermal mass to get that 'sink off, it's quite large and would dissipate the heat with ease.

 

[Les Sarile]

As for the power supply, I've taken a look at it, but Nikon in their infinite wisdom decided to have a heatsink soldered directly to the board that overhangs several components, including some capacitors. Getting those out for testing is going to be a bit of a pain in the rear, so I might wait until I buy the hot air gun to be able to properly remove the heatsink entirely while inspecting it, as I don't think my cheapo Hakko-knock off soldering station iron has the thermal mass to get that 'sink off, it's quite large and would dissipate the heat with ease.

I would certainly not recommend removing any components at this point - simply check the outputs of the power supply either at the source or on some components. I don't have schematics but if the primary logic voltage is 5VDC, it should be that ±0.25 with less then 5mVDC of ripple. Given the era, other logic voltages may be supplied but should also be highly regulated. I anticipate there may also be 12VDC and/or 24VDC outputs but those don't necessarily need to be as tight as logic voltage.

 

[Daniël Oosterhuis]

I would certainly not recommend removing any components at this point - simply check the outputs of the power supply either at the source or on some components. I don't have schematics but if the primary logic voltage is 5VDC, it should be that ±0.25 with less then 5mVDC of ripple. Given the era, other logic voltages may be supplied but should also be highly regulated. I anticipate there may also be 12VDC and/or 24VDC outputs but those don't necessarily need to be as tight as logic voltage.

I have to be honest, I'm a little squirmish to poke around in the PSU to measure voltages, given the PSU does have 230V AC going to it which it steps down to the appropriate voltages. I wanted to specifically check the capacitors, and doing that with them still attached to the board will give inaccurate readings on the little component tester I built as a kit.

 

[shutterfinger]

I have to be honest, I'm a little squirmish to poke around in the PSU to measure voltages, given the PSU does have 230V AC going to it

With power off/disconnected trace the output of the step down transformer to the rectifier output then to the next component connection and mark it. Make your test measurements there.
The +5VDC logic will likely be separate from the other sections with 24VDC for the drive motor and likely stepped down by resistors to other voltages used. Its easy to avoid the AC in.

I started out on tube type radios and TV's where 120VAC was stepped up to 240VAC or 320VAC.
I went to disconnect a high voltage anode on a malfunctioning solid state TV at a customer site (hospital) with rubber sole shoes on standing on a rubber mat over concrete. My fingers were 1/2 to 3/4 inch from any metal but the high voltage arced to both hands, and went down my legs to my heels which felt like someone had picked me up and slammed me down on to the floor. Some previous incompetent person had turned the high voltage gain up to maximum so it was around 90KV instead of the normal 25KV. I had previously discharged a hundred high voltage anodes without incident.

 

[Les Sarile]

I have to be honest, I'm a little squirmish to poke around in the PSU to measure voltages, given the PSU does have 230V AC going to it which it steps down to the appropriate voltages. I wanted to specifically check the capacitors, and doing that with them still attached to the board will give inaccurate readings on the little component tester I built as a kit.

Do not poke around if you don't have basic electronic skills as it can be lethal (50v and higher) and/or you can introduce even more faults. Generally line voltage is isolated particularly in this combination of electronics and everything else is low voltage. But I don't have schematics and just guessing.

BTW, removing a capacitor just to check it is not commonly done in repair work. You can either by sight see it's defective (wild discoloration or leaking) or check in-circuit if it is working or not.