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Big Dave

2901- Yellow splotches in gray areas

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Is this happening on all paper widths?

Can you scan in an emulsion test print together with a screenshot of the readings.

Have you tried loading in the backup data from a time before this started happening?

Edited by Dave S

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Hi Dave, yes, this is happening on all paper widths, sizes, and paper types.

5" Luster

6" Gloss, Luster

7" Luster

11" Luster

The funny thing is that the daily setup does not have this issue because the gray scale isn't fine enough (or light enough) to have this problem show. 

Here is our daily setup from this morning :

     daily setup results:  https://imgur.com/N6qMe5i

     Daily setup : https://imgur.com/XbsIPQe

The problem started 2 days ago.  I tried to replace the Image Processing Board, but same problem, so it's happening AFTER the Image Processing Board.  The MLVA lamp is a month old. - Haven't checked the dichroic filters or MLVA head (don't know how)

 

 

 

 

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I'm wondering if the CD is a bit weak. I would expect a higher black reading. Something like 2.10 is ideal.

To me it looks like a bad LUT problem. So worth trying to load in your backup data. You can always make a backup of what you have now before doing that.

I personally would do an all data backup in service mode.

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Thanks Dave,

I spiked the CD yesterday evening - Output check - CD pump for about 90 seconds - no noticeable difference between yesterday's prints and today's prints.

I'll do a backup and a restore in a bit and report back.

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Question on backup data restore - any guidance on WHAT to restore ? Or restore ALL data ?

We've been doing service level all data backups whenever there's a "change" to the system - and not nightly / weekly backups - so the last backup I have is from December ! of 2017  :  :wacko:

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90 seconds on the rep pump will not do much. Remember the tank size is about 20 litres (assuming it's not SM).

You would need to replace about 2 litres of CD to see a difference.

I would restore all data, it doesn't matter too much if it's that old, do a few daily setups and see if the problem has gone. It will prove whether the problem is data related or not.

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Awesome !  Performed the full system all data restore, 2 daily setups to get it back in balance, print out the 2 test prints and no more yellow bits !!

I Thank You very much Dave S !

I just need to perform those backups a bit more frequently. 

Now to balance all the papers and do another service level all data backup !

:D:1310_thumbsup_tone1:

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Ok, less 8 days later, the problem has returned.

Performed another data restore - and this DID FIX IT.

The question now, is why ?  Why did it happen again, so quickly ?

How can we prevent this issue going forward, or is this a precursor to "something else" ??

I cloned and installed a new 128GB SSD at the end of November 2017 -- so the hard drive is "good".

 

 

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The first thing to check is the chemistry is spot on.
For example if the BF is weak it can struggle to control the light areas on the 18 step setup prints. Check the rep pumps are outputting correctly.

Next thing to check is the colorimeter unit, make sure the pressure plate is good and is pushing the print up towards the colorimeter head.

I wondering how you do a trim maintenance on the SSD drive when operating with Windows 2000?  I personally would be wary of using an SSD with Windows 2K.
The machine does a huge amount of temporary file writing when printing, so this could be causing problems with an SSD.
It may be worth going back to a standard SATA drive just to eliminate this as the cause of the problem.

 

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Chemistry seems to be OK, no major ups or downs on the daily setups (sorry, we don't run control strips).  Chem usage is good, but I will double check the pump output amounts later today.

Colorimeter unit and position is good -- Only issue is the calibration plate is a bit on the old side. -- Last replaced back in Oct of 2009.

TRIM isn't/can't be enabled on Win2K (from what I could find out) but no un-healthy side effects from it so far.  Other people say that the system might be a little slower, but it's more than fast enough for us.  The usable space has not deviated at all in the past 8 months - that I can tell, but I've not really thought about it. -- I do have a good working HDD inside the machine, if the SSD ever fails, I just have to move the SATA/power cable from the SSD to the HDD, do a system restore and we're back up.

BTW, it's an 80GB SanDisk SSD, not 128gb.

 

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Hi Dave S,

Replenishment pump output amount checks - looks mostly good. :unsure:  Maybe under replenishing a tiny little bit.

previously: CD = 60.0 / BF = 58.1 / STB = 111.0

NOW: CD = 58.3 / BF = 57.0 / STB = 113.3 - each run 4 times, measured and divided by 4

 

As far as the SSD TRIM function, there are quite a few others that have mentioned that they are running on older OS' with SSDs and not having issues after use for over 2 years -- and these were posts from 2015.  This article, from 2015, seems to say that even without TRIM, it might wear out your SSD a little faster, but nothing to really worry about.  https://arstechnica.com/gadgets/2015/04/ask-ars-my-ssd-does-garbage-collection-so-i-dont-need-trim-right/

The SanDisk I installed was bought in 2017, so should be good for at least another 10 years - unless it has a catastrophic failure at some point -- it was on sale when I bought it !  -- advertised as an 80 GB drive, 75 GB total with 64 GB free. -- lots of spare cells to use.

I can swap SSD to HDD if you think that's a plausible suspect in this data corruption.

Thanks !

 

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The only other thing I can think of is doing the initial setup again, together with the load voltage adjustment.

Clearly it's some kind of data problem, so may be worth trying to swap the hard drive for elimination purposes.

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Hi Dave S !

Merry Christmas, happy new year and all the other cheery stuff that happy people say to other happy people.....

Finally got it nailed down, identified, replaced, and everything is BETTER than before.

Past month or so, our daily setups have been ALL over the place.  Made me think it wasn't saving the previous day's values so that it was starting from scratch EVERY day.  Would take 3-7 daily setups to get to "ok" values close to +/- 0.0.... the initial daily setups had correction values of up to +20, then -19, the +16, until it got back to 0.... if you add up all those numbers it's pretty much back at 0 where it started from, but it looks "normal", not white like the first print.  It started much lower, but the # of daily setups remained fairly constant at 3 to 5 times every day, just the initial correction values kept creeping up every day.  One day, we had to do an emulsion # change on the 6" matte, and it was bad.   After the 3rd fail, the top 3 or 4 lines were a bright yellow.  Didn't want to continue, so cancelled out, tried printing something, it came out mostly brown with a couple of black spots and looked like doo-doo.

So, started looking for answers, to "yellow prints", and found these:

 

Immediately changed out the Drive Voltage PCB, and the magenta cast we've had on our daily setups (that we've asked everybody how can we "fix" it) is gone !  As is the Yellow "splotches" in greys that we've had here.  Every thing seems to be back to normal (its been a week now).

Just thought you would like to know how we got rid of it.

Have a great holidays, enjoy your time off (if you get any!) and be well !

Big Dave

 

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Hi Big Dave!

Thanks for posting your findings.

The drive voltage PCB is a common failure when you are getting big sudden colour shifts, however it tents to show up with the prints going red or brown. Turning the power off and back on again and the colour suddenly corrects are classic symptoms of this PCB being the cause of the problem.

I guess in early failure the colour shift results maybe are not so dramatic.

Merry Christmas, and a Happy new year to you too.

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If on QSS29  color suddenly changes to brown - red, or similar color then drive voltage pcb is faulty. Many times had to repair boards with this fault.

If have red, brown, yellow dots, or small lines - usually one image correction pcb is faulty. If to switch boards ( two the same boards on QSS29 ) - often see error 6820-0004. The same image correction pcb used on QSS28, QSS29, QSS31 and QSS34 series minilabs ( not on all models ) .

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