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kodakman7

Posterization on 2901- uniformity error

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Good evening- I recently experienced a sudden appearance of posterization onto our prints (from 1 print of an image being perfect- next consecutive print of the same image is posterized). We re-ran the daily setup, uniformity etc. No change.

Ran the MLVA voltage adjustment- no bias shown and prints went yellow.

We then changed lamp, and the color came back to near normal over a few setup prints and the printer balanced, but the posterization continues.

The printer has the Image Processing board with RAM on the board- not on daughter board

We have been having intermittant ARCNET errors for a little while. No errors appearing lately.

Mosly the problem is apparent in light tones, but is also visible in darker areas where there is gradual changes in the contrast.....??contrast problem

Have now restored a backup- done MLVA lamp change balance and balance fine, but we get a uniformity error 6088-0026 but no reference for this in my service manual.

Where do I start looking for a solution to this problem?

Examples attached

Many thanks in advance

upload501_sml.jpg

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What does the 18 step print look like?

If the chemistry is definitely good, I'd be looking at the calibration plate/ colorimeter unit.

 

6088-0026 the manual says, The value calculated during the weekly setup is abnormal.

The MLVA unit tube face is dirty.
The MLVA lamp has deteriorated.
Check the gain value. → Printer Mechanical Adjustment → gain adjustment.  (A value of 0 or 255 is abnormal)
Adjust the gain value when it is abnormal.
The preamplifier PCB is dirty or defective if the adjustment of gain value can not be performed correctly.
Check the load voltage value. (A number other than 400 or 680 appears when the Load Voltage Adjustment is performed normally)
Adjust the load voltage value when it is abnormal.
The MLVA unit is defective if the adjustment of load voltage value can not be performed correctly.
Drive voltage PCB
Data output PCB
Image processing PCB
Calibrator connecting PCB
Printer control PCB

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If print suddenly become yellow then try to change drive voltage pcb. When this board doesn't work properly then few prints are printed well, but suddenly other photo can be yellow, yellow - brown, or red - brown. Many times had to repair these boards. After board repair prints where stable and no color changes anymore. 

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Have tried suggestions- new tank bleach and first 2 stabilisers new also.

Gain adjustment done- not clear as to how to adjust the gain value though.

Ran load voltage also

Daily setup below- bit of a green tinge though white is clean at the ends.

It was true that the posterization appeared from one print to the next on a multi print order.

Should I replace the Dev next and do a full paper setup from scratch.........?

 

IMG_20200529_0003.thumb.jpg.308504fb85a54f45df0fd69992a7d6c2.jpg

IMG_20200529_0004.jpg

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21 minutes ago, Minilab service said:

If print suddenly become yellow then try to change drive voltage pcb. When this board doesn't work properly then few prints are printed well, but suddenly other photo can be yellow, yellow - brown, or red - brown. Many times had to repair these boards. After board repair prints where stable and no color changes anymore. 

Is that the board that is part of the MLVA or another? Which board number?

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It is not board inside MLVA. This board is beside it.  Drive voltage pcb - J390638 . When it is faulty test and prints suddenly can become yellow,  yellow - brown, or red - brown. After making daily test color balance is acceptable, but real photo are not very good.

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Quote

 

Here is some additional information on this problem. Really hoping for an answer or direction to resolve the problem.

As advised, the problem appeared between consecutive prints- partial scans of thos are  attached- with the 1st and 2nd ( before and after) prints. The second/after print also shows a clear demarcation of the start of the issue (scans are the left half of a 12x18in print)so it printed properly for the first 2 inches and then was in fault. So presumably this is either an MLVA problem itself, or a problem with something driving the MLVA. ......?

I have discounted the colorimeter as a cause and logically, didnt consider chemistry as a direct factor given the nature of the onset

For the record, the tank mixes of dev, blx and first 2 stabs are all now fresh and new- last few days. The 16,17,18 strips came back a little (we do a manual replenish weekly to compensate for low volume so presumably have been over-replenishing that!)

The MLVA lamp is new

I did swap over the the MLVA drive voltage PCB with a spare board I have but no change- though could be problematic I guess.

The MLVA head has been cleaned

Paper setups have been run as new paper, and assigned to a different cassete.

We get the 6088-0024 error on performing daily uniformity correction

The #1 strip on 18 strip test appears to have a slight green tinge (as do others but less noticeable- see earlier file upload)

If I print something as monochrome the posterisation problem is not apparent, however the prints (dark colors espec) are a little red/muddy as a monochrome.

Gain adjustment completes satisfactorily. When I tried to enter Exposure Image Correction afterwards, I got the 6029-0003 MLVA auto gain execution error flash up but was able to print

Load Voltage adjustment completed without error- values dropped from 600+ to 400+/- ,   and the bias voltage dropped to from 137,79,0 to 0,0,0

Tried to do #1 and #2 test prints after above and before a daily or weekly setup and the prints were yellow/light orange. Then weekly setup- 18 step similar (yellow/orange) - warned of 3 stop correction- but then profile print looked okay-ish though the black print was very 'muddy'. Uniformity not good at this point and not performed through the following steps.

Ran weekly setup again- 18 step print red toned this time but more density-  Got the 1034 MLVA light intensity is low msge- Execute Correction?

Ran weekly setup again - 18 step density iproving though a colour range from left to right- bit more green to the right side. Got a 1034 MLVA light intensity is low msge- Execute Correction?

This process is being repeated at time of posting!!!!

For some history, this MLVA head was installed about 5 yrs ago but to my recollection there was no initialisation done and we didnt have the MLVA data disks for this head (second hand machine). We re-set up at the time as it was less than 24hrs from me going overseas for a month. It has largely been okay until now. Athough looking back comparing daily setups to  some preserved setups from the original MLVA head (with original data) this head may not have had the clean neutral #1 strip that the original did.

Should/could a data initialisation help? What is required and what is the process to perform this?. What if I dont have the original MLVA data for this head- can data from a different head be used?

Is it likely a PCB or the actual MLVA head itself? I have another s/h MLVA I have been holding in reserve pending a clear failure, but this is nothing like how my first head failed so i am unsure?

Does this information help or point to something?

Thanks in anticipation.

 

IMG_20200529_0001.jpg

IMG_20200529_0002.jpg

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On 5/29/2020 at 6:45 PM, Minilab service said:

It is not board inside MLVA. This board is beside it.  Drive voltage pcb - J390638 . When it is faulty test and prints suddenly can become yellow,  yellow - brown, or red - brown. After making daily test color balance is acceptable, but real photo are not very good.

Which component fails? Capacitors?  Do you do repairs on the boards? What is cost to get one repaired?

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@kodakman7, did you get this resolved ?

what was the solution ?

we replaced our drive voltage pcb last November/December, but on recent power up, it was giving us similar issues on the daily setup as we had before, where it was going yellow, and correction values were VERY out of range.

 

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drive voltage pcb deteriorate with age so (USED pcb replacement ) could be short life. Find / Buy NEW drive voltage PCB  . . . I have  :-) Brand new .. Qty. 1 piece in stock

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