Jump to content

Bluish White after connect resistor


Studio01
 Share

Recommended Posts

Today I had to connect the 1,3K resistor due to 24 pixel line.

After that I adjusted the flicker and calibrate paper.

Now, my DKS 1510 prints white color a little bluish.

I have calibrated paper severla times, replaced paper.ini from

backup, adjusted densitometer and no changes.

My surprise was that I decided to make PRNU to try to correct it

and the PRNU prints that I have to scan later, to calibrate it, have

a perfect white. I calibrate PRNU and after that I still have a bluish-

greenish in the white color.

Does anybody know a way to correct it?

Thank you.

Studio01

Link to comment
Share on other sites

All of this test should be done without compensation filter present.

LCD Response is bad, check help on the right part to know what to do, I can check manuals but not before monday afternoon.

When testing polariser tick first 3 boxes, also it is looking bad, also check help.

Gain is also bad.

Maybe you turned polariser ring or squarre unintentionaly ?

Link to comment
Share on other sites

Finally !!! a topic or question worth consideration - IF WE APPLY RESISTOR _ WHAT IS NEXT STEP ??

Someone called me yesterday due to the "bluish spot" on the pictures and 24p line. Today I spent whole day and joined "upgraders"community.

Status - Machine bought refurbished and installed 6months ago. Reported now with 24p line and blue spots on pictures. Permanent problems with paper calibration, lot of magenta and blue;Impossible to shot a serie of equally coloured pictures. Epson driver with 1.1kohm resistor plugged. Machine with non-original LCD block (off course... ). didn't see it was R-marked or not.

I started from scratch since i was expecting rathero

1. check optics - OK. Zero of filder disc - OK. BLue filter disc with some traces but I finally considered them not impacting the issue.

2. printed some test pictures, NOK - 24p line.

3. Checked flicker - bad -> corrected -> OK.  One PRNU printed - OK

4. Half hour later printed PRNU for scan - NOK - 24p line and several clones...

5. Play with epson.ini parameters - no score.

6. Replaced original 1.1kohm with 910 ohms. It helped - stripes are gone. Note - machine is not upgraded (yet) with the swith-off LCD unit - will be upgraded soon, serviceman who did on-place installation promised to send upgrade kit.

7. removed original filters.

8. Set flicker - OK.  

9. I was unable to set the polariser correctly. Red was always BELOW green and blue. Values were lower than typicaly met.

10. Gain was also catastrophic - below expectations - to get the difference 780-850 i would have to raise value above 230 which is generally not recommended. I left 225.

11. LLCD Stability - massacre - full of errors. skipped that.

12. Didn't perform LUT which should follow Stability - I was affraid to make the massacre. on the LCD response. I think I did a mistake here...

13. put work filters did paper calibration. Scored, however it was tricky since this was my first calibration after 4 years break,  a forgot a lot of things :P

14. checked for new filters - Machne got for new set. Watch out for exposition times they might be tricky. Done.

15. PAper calibration - took 4-5 shots but scored.

16. PRNU - 1 step at 7 - scored.

17. Quality pictures - quite nice sharpness I decided to skip Piezo. Noted that each objectif had different picture colour. that was not a normal thing... Will attach picture later on.

18. Few test pictures printed - were IMHO little bit dark pictures itself not really representative - customer, which knows better photography than me, was satisfied. We didn't print any serie.

Remarks and questions to the all people doing installations and service.

A. Question - when machine set in default place - does the the man check all zeroes (LCD, filter disk, expohead) ?

Machine had LCD and head zeroes off tolerance but since whole optic line was calibrated earlier by service i didn't touch it. but it was suprise to see red values on the screen...

B. Remark - in my life I have seen lot of machines, some had problems with polariser but NONE had such problem I had today. It must be related to the resistor. the same with gain. Maybe I should go much much lower with the turn but it was not the point - you know point so i will not list it. :)

C. Question - Is there a formal calibration procedure available for the reworked Epson driver and LCD block ? is it really true that with resistor mounted, gain can be adjusted more than 230 value in order to get proper difference value ?

D. Question - I dont remember such differences on the pictures. FIrs one i get was light, second was darker and tha biggest one - was green. could be rather a result of LUT not performed ??

ANy reply and comment appreciated - feel free to answer here and on private of you feel it might be too...risky. BUT PLEASE COMMENT.

Link to comment
Share on other sites

Thank you Relaxia but I've turned all to back state:

- Replace all DKS folder

- Disconnect resistance

And after some prints is still the same, so:

Perhaps when I mounted back the MSB piezo I touched

the LCD polarizer and moved it just a little when trying to

insert the screws on the right place.

I attatch a photo: is that the "polariser ring" that you say?

Right now I'm gonna plug the resistor again, screw the piezo,

and make some prints slightly moving with my fingers that

polariser to see any affection to the prints.

I supose that the movement have to be made by milimeters.

I'll tell you

Studio01

Link to comment
Share on other sites

OK Sucess!!

After rotating slightly the polarizer rig I get a whiter print.

I don't know how to find the OPTIMAL position but I think

I will leave it just the way it is now.

So, what happened was:

When I screw back the piezo again, after soldering the

resistor, trying to find the holes of the screws, I moved

the position of the polarizer rig.

Thank you all for your help.

Now I hope to have more time until deffinitive 24 pixel line

comes again.

Studio01

Link to comment
Share on other sites

T that's the polarizer. the bottom one - adjustable  ;). generally it is lightly blocked by 3 plastic screws not allowing him to move during work.

it helps sometine during adjustments because minimal moves can screw up whole work.

I assume you didn't set the polariser - just fixed the state to have machine working. so all questions are valid.

Link to comment
Share on other sites

What is the compensation filter?

Is necessary to take it out to do Polariser ajustments.

Do you have any image from it?

---------------------------------------------------------

Another thing I didn't comment before, I had a 110,3K

resistor in my PCB ready to plug. Why this value?

When 24 pixel line came I connected it (I didn't realize

its value) , and I had 3 weeks more free 24 pixel line

problem.

After 3 weeks, problem came again, so when I wanted

to put a second resistor I realized that the first was 110,3K

and I change it for a 1,33K, the one that is recommended

by Kis.

Do you know, why I had a 110,3K instead of 1,33K?

Is not strange that with 110,3K only had 3 more weeeks

without problem.

  

Studio01

Link to comment
Share on other sites

What is the compensation filter?

this is the insert in the expo head containing CP or CC optical filters. they are required for proper exposition times setup.

Polarizing, gain and basic optic settings you are doing without filters - for PRNU from scratch u need R40 and N40 fiters. For final PRNU step and final machine work u need filters the machine is requesting after measurement.

Resistor... Studio01, did you measure the resistor or just looked at the stripes ? you had 1,1k resistor but precise one 1% tolerance - they are marked with 5 or 6 stripes :)

by the way I dunno why everyone are talking about 1,3k but all pictures are showing 1,1k...

As promised pls find quality pictures from my yesterday job. Note - each lens - different color.

Link to comment
Share on other sites

Thanks for the photos, this is the filter that I suposed.

About resistors, I measured the resistors with my tester.

The resistor that was on the epson PCB was not 1,10K, was 110,3K!

...with 6 stripes

Now I've put the "teorycal right one" as Kis recommends = 1,3K

Studio01

Link to comment
Share on other sites

The resistor that was on the epson PCB was not 1,10K, was 110,3K!

Now I've put the "teorycal right one" as Kis recommends = 1,3K

Studio01

OK so someone missread the value - resistor was giving nothing - too big.

I got the point what this resistor is doing.

Studio01, pls take the multimeter and check the voltage in the point marked "15.5V" in the frame with arrow - above the component you were soldering the resistor.

If such solutions are helping and this is the first time you are doing this - i would recommend to start with bigger R values - starting from  3,3k, then 2,2k, then 1,3k (KIS) than 820 ohms (last stand - rememmber i dit put 910 ohms and it worked. )

I can't predict how long this will upgrade will last. Theoretically LCD with upgraded board can work 6months to 2 years but you 'll never know when it fails. from the second side you have next rework steps. so theoretically you could work longer...

Studio01 if you still have machine offline - put 3,3k and try to setup the machine with this. Check the result. DOn't worry 3,3k is safer than 1,3k, however it could be interesting to know it is working or not and how long it will last. if my theory fails you can still go back to 1.3k means original KIS rework.

Link to comment
Share on other sites

I am sorry but my DKS is online right now, with 1,3K

resistor connected.

Are you saying that I will long LCD life if I put first

a 3,3K resistor, and when fails change it for a 1,3K

resistor, than putting directly a 1,3K resistor?

Do you recommend to change it for a 3,3K until it fails?

Studio01

Link to comment
Share on other sites

Are you saying that I will long LCD life if I put first a 3,3K resistor, and when fails change it for a 1,3K resistor, than putting directly a 1,3K resistor?

Do you recommend to change it for a 3,3K until it fails?

Brefly - YES.YES.:)

However can't say is it enough and for how long it will last.

Facts.

1. The modified part is a voltage regulator which gives 15.5V for whole subassembly. By adding the resistor we are changing this value. I asked you to measure that - I am expecting 18.5V with 1,3k.

2. Changing the value to 800 or 820 ohms which was suggested on the forum is raising the voltage to 19.7V.

3. I personally did modif with 910ohms and it is working. and PCB modified had 1.1k instead 1.3k.

4. conclusion - We know that with voltage raised from 15.5 to 18.5 machine can work without stripes from 6months to 3 years(confirmed case). We know that raising to 19.7V ohms will give another year.

5. Thesis - So why can't we start with lower tension values and give ourselfs more time ? 3,3k results around 17V tension. if the stripes are gone - note IF - it is ok and we can continue work. It is less stressing for the LCD.

6. the disadvantages - I CAN'T predict how long this setup will work - possible it won't work at all - possible that 6months - possible that much much longer.

Solution was not tested in practice and not measured - voltage results are calculated from the circuit LT1963EQ application note, KIS is using it here in standard way.

Everything looks reasonable and safe, since we are working within the limits established by KIS. nothing to loose - lot to score.

Studio01 - you have started rework and you have FRESH LCD matrix on the early beginning. I am trying to convince you to make this experiment. Start with with 3.3k, buy for future 2.2k , 1.3k U have already, buy as well 910ohm and 800ohm (the best with 1% tolerance - remember).

Parts are cheap, if you know soldering it is relatively easy work to do, so will not take lot of time.

I replaced resistor without LCD removal, only driver was extracted - so no needs to do extra works with calibration. Little bit more work with assembly but can be done, supporting person for 10 min could be much more helpful here since PCB support must be unscrewed in order to put the LCD flex tape in the connector correctly.. :)

Up to you :)

Other conclusions ... I don't have enough knowledge to find why the stripes appear exactly in one place or near this place, why raising the voltage helps and how it really works. this needs a study for someone more experienced in LCD technology.

I also know that this defect can be eliminated - LCD regeneration. I dont know how and for how long it lasts but it is possible.

PS. EURO2012, Spain- Italy 1:1  ;D

Link to comment
Share on other sites

Thank you Relaxia,

At the moment I only own a 1,33K resistor that is installed and working,

so, until I can buy the others I'll have to keep this one in my DKS and

work with it (a couple of days?).

When I am able to buy it I can change the 1,33K instaled for a 3,3K

that you recommend first.

Studio01

Link to comment
Share on other sites

OK Sucess!!

After rotating slightly the polarizer rig I get a whiter print.

I don't know how to find the OPTIMAL position but I think

I will leave it just the way it is now.

I was right then when I wrote that you moved that square by mistake, maybe I will play a Lottery now when my guessing is so good  8)

Idea is to get best difference values in the RED first as the starting point then move it slightly to get this order of values: GREEN, RED and H BLUE as the lowest value.

This is the procedure from help MENU which appears if you press the lamp icon on the each adjustment screens as well as on the polarizer adjustment tab:

To do before

Offsets

To do after

LCD Response

Specific Tools Needed :

Silicone paste and black electrical tape.

Goal

To position the polarizers in their nominal position with regard to the LCD.

Only this position will allow a correct blackening of the LCD in Red, Green and Blue.

Instructions

Entry Polarizer

Since this adjustment is made before the final assembly of the machine, we only need to verify that it is still in the correct position.

The entry polarizer is positioned in its theoretical position (the polarization axis is in the axis of the flat cable. A reference mark is put at 45° from the axis of polarisation on the ring of the polarizer (this mark is made at the factory). This mark must be aligned with the corner screw placed at 45° on the left from the flat cable (viewed from the Top).

Note : To access the entry polarizer, remove the upper panels, release the exposure head by loosening the 4 black knurled plastic knobs. Be careful not to damage the printed circuit boards or cabling

If the positioning is correct, check the locking of the ring. If necessary lock it again using silicone paste by dabbing a bit on the external ring.

Analyzer (exit polarizer)

1- Rough adjustment.

If the position is badly set it is necessary to perform the following rough adjustment:

Select the "Camera" TAB, select and display the PHRtension.png (Black, Grey and White pattern) on the LCD, exposure disk on position " white light " (HOLE).

Remove the side panel of the exposure chamber (lens turret access).

Visualize the modification using a little mirror or a piece of paper that you’ll place on top of the lens area and search for the position of the polarizer that yields maximum contrast. By going beyond the maximum position the black becomes reddish. Go backwards and once the best position reached proceed to the fine tuning of the analyzer position.

2- Fine Adjustment.

Note : During all these adjustments you have to remove all filters from the exposure head in order to obtain the maximum of light. To move the polarizer open the side panel of the exposure chamber and close it to proceed with the measures.

Maximum Contrast in Red

Select (tick off) only "RED" .

Click on "START" and make sure that the side panel is closed off during the measurement.

Wait for the display of the second "difference" measurement and keep note of its value.

Next carefully move the polarizer 0,5mm towards the left or the right and repeat the difference measurement. The goal is to find a position of the analyser that will give the highest difference value in red.

Best compromise in Red, Green and Blue.

From the previous position if you progressively move the analyzer to the left (anti clockwise), you will pass by a maximum in Green and then by a maximum in High Blue. Looking for the best compromise consists of increasing the contrast in H Blue without losing too much contrast in RED. This position is found within a range of 1 mm to the left of the maximum of contrast in red.

Tick off the red, green, H blue boxes.

Move the polarizer to the left (from 0,5 to 1 mm). Note the values of "difference" for the 3 colors.

If the contrast in Red falls under the H blue, you must come back to the right. If not, you can continue to move delicately to the left to slightly increase the contrast in H blue. The contrast in RED must be over the H Blue and below the Green.

Example of value after adjustment:

RED :      353

GREEN :     378

H BLUE :     349

Locking the analyzer :

The rotating ring of the analyzer must be permanently secured (locked with silicone paste) when the LCD response confirms that the adjustment is proper. Meanwhile the ring can be temporarily immobilized using a piece of black electrical tape.

Verification

The difference in red must be in between the green and the H blue and the difference in between GREEN and H blue must not exceed 60.

The LCD response (see "LCD response" TAB) must confirm the correct adjustment of the polarizer.

Link to comment
Share on other sites

Are you saying that I will long LCD life if I put first

a 3,3K resistor, and when fails change it for a 1,3K

resistor, than putting directly a 1,3K resistor?

Do you recommend to change it for a 3,3K until it fails?

This is hard to say as this value of 1.3k set by KIS had to have some testing behind it, but you can try.

I installed on our office machine 3 pin rail, in the middle is ground and on one end is 1.3k resistor and on the second end it is 820Ohm resistor and in that way with the jumper set between ground and one or another resistor I have all possible combinations (without resistor, with 1.3k and with 820ohm resistor) and for the future I do not have to disassemble the MSB, just set the resistor in one off that 3 combinations  8)

But if you want to play with the values maybe it is easier to install variable resistor and then you can change the value by screwdriver to any value up to the variable resistor maximum value.

http://www.kpsec.freeuk.com/components/vres.htm#presets

Link to comment
Share on other sites

Thank you Pskaro,

Now I have adjusted the polariser and all is OK, today has

been a "foolish day", I've done more than 1 thousand photos

and no problem.

I was thinking about an extended cable to allow me to change

resistor without disasemble anything.

Studio01

PD: Experience is the key to know what we're doing

wrong the ones that touch delicated things.

If I had to assemble-disassemble piezos often I

would know to be carefull with the polariser filter.

Link to comment
Share on other sites

Thank you Pskaro,

No problem  ;)

PD: Experience is the key to know what we're doing

wrong the ones that touch delicated things.

I have something like 13 yr experience with KIS minilabs  ;)

I have similar situation with one customer on DKS750, and I was on the phone for almost 1 hour, and conversation started that he was getting the bluish pictures, but he only moved a machine position.

After hour on the phone, testing everything he told me that he cleaned the area near polarizer filter (circular on the DKS750), and immediately I knew what was going on and just told him to find the black silicon mark (only on DKS750) which is showing the factory set position, and that was it  ;)

Because off that storry I suspected that you maybe moved the polarizer square ;)

On the end it was funny story "I only moved the machine position and my pictures are blue, what happened"  :)

Link to comment
Share on other sites

But if you want to play with the values maybe it is easier to install variable resistor and then you can change the value by screwdriver

Well I was exactly thinking about it, but finally gave up. Didn't want to mess too much in the heads. we don't have too much people skilled in electronics :) and this is anyway very easy operation to kill all LCD subassembly. Just forget to set the potentiometer on the middle of the scale and leave it in zero position.

Resistor ... With a little bit of exercises in tricky positions you can desolder the resistor without removing PCB from the assembly  ;D

Regarding the polarizer - as you said the entry polariser is fixed by manufacturer and usually not possible to move. the output one has 3 locking screws and should be fixed as well ...unless someone from service forgot to fix that after settings. any cleaning touch should not be able to move it...

Pskaro could you check my questions ? remain actual - what is the impact of this modification to the optical parameters?

LCD with with resistor is not possible to set according to the instruction.

Maybe for polarizer settings I have just remove the jumper and do everything according instruction ? then mount the jumper and forget about further polarizer settings ? readings are gone but polarizer will be correclty positioned...

BTW someone knows where to buy nylon screws for the polarizer in LCD? need to replace one totally massacred by some ....incompatible...servicemen before.

Studio 01

I was thinking about an extended cable to allow me to change resistor without disasemble anything.

Way to go, amigo :), nice idea. Fix the wires, Place some kind of pin female connetor fitting tightly resistor legs at the end and ... life's easy. And make a licence for this rework  ;D

Link to comment
Share on other sites

Pskaro could you check my questions ? remain actual - what is the impact of this modification to the optical parameters?

LCD with with resistor is not possible to set according to the instruction.

Maybe for polarizer settings I have just remove the jumper and do everything according instruction ? then mount the jumper and forget about further polarizer settings ? readings are gone but polarizer will be correclty positioned...

BTW someone knows where to buy nylon screws for the polarizer in LCD? need to replace one totally massacred by some ....incompatible...servicemen before.

I never had an issue with such a big problems after setting up the resistor.

I would suspect maybe some current leak on the PCB due to the some soldering leftover on the PCB, try changing the PCB first ?

Or maybe you have a problem with the polarizer parallelism to the LCD, and maybe because off that and some movement off the polarizer glass inside, you have such a big difference between the lenses ?

I would even try with another polarizer square from some other broken unit  ;)

I had an issue when one the polarizer square which from the factory was not screwed properly and that affected the image position when LCD was rotating.

Link to comment
Share on other sites

This is how I done it, by soldering both 1.3k and 820 Ohm resistor and left a possibility to chose which one will be connected or none, my soldering could be better off course, but the heat on the pins started to melt the plastic around it so I had to be very quick  ;)

lcdz.jpg

Link to comment
Share on other sites

My 1510 has that resistor fitted in, 24 pixel line is there after 100 prints and tech told me to switch jumper on, but the line is still there after doing prints for a while..?

24 line havent been there before i thing (used machine), this is firts time to get rid of it, why jumper wont work..?

In winter that wont come that easy, but when air gets hotter it´s there fast.?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...