Suddenly changed on color

[Qssoperator]

From the Qss37HD, 20 copies have been printed, 2 prints have different colors ( green tone about 3 color key differences) and 18 prints are good. Would you please share your thoughts about this problem? Thanks 

[alexvigor]

It's likely the AOM-driver problem. Try to replace it.

[Qssoperator]

@alexvigor I have replaced the AOM from AliExpress but the same issue. I’m not quite sure how the Chinese AOM though. 

Edited May 7 by Qssoperator

[yustas]

Some AOM drivers from China are not of good quality right out of the box.
Try another one.

 

[alexvigor]

6 hours ago, Qssoperator said:

@alexvigor I have replaced the AOM from AliExpress but the same issue. I’m not quite sure how the Chinese AOM though. 

When someone reports a problem, please share your commited attempts to solve it so people don't waste time on tips you've already tried.

Regarding your problem - if it is exactly the same after aom repl - next places to check are - Laser control PCB (reconnect j/p 1502 1508 1543), laser driver (very unlikely to fail), coaxial cable & bnc connectors (very unlikely to fail), G aom-crystal, G laser gun.

First of all I'd try another AOM-driver, as yustas advised. If it doesn't help - check connectors and try another laser driver (although if G laser is bad new laser driver can make it work fine for some time, but laser gun will fail eventually). 

Pay attention to problem progress. Lasers die slowly and frequency of bad prints will increase slowly, AOMs die rapidly.

Edited May 7 by alexvigor

[yustas]

Could you place an image with defects here?

[Qssoperator]

I will provide an update once the AOM is replaced again. Please see attached photos. The right side photo was the problem I am trying to fix.

[yustas]

No “Purple Rain.” That's good.

That means that in 99% of cases, you have a problem with the AOM driver.

[Dave S]

1 hour ago, Qssoperator said:

I will provide an update once the AOM is replaced again. Please see attached photos. The right side photo was the problem I am trying to fix.

If the symptoms are identical (the same amount of colour shifting) as before you changed the AOM driver, the issue is likely to be the laser head itself.

4 hours ago, alexvigor said:

When someone reports a problem, please share your committed attempts to solve it so people don't waste time on tips you've already tried.

I couldn't agree with you more. There are also so many time wasters who make a post then, never answer any questions, or never come back to update what the final fix was.

[Qssoperator]

@Dave SIn facts, before replacing the old original AOM with the new Chinese AOM, the green tone appears 1 to 2 prints a day and sometimes doesn’t appear. Afterwards, when the Chinese made AOM was installed, the green tone appeared more than the old AOM and more occasionally during the first 4 hours of production. After that doesn’t appear until the closing time.

[Qssoperator]

@Dave Sthe amount of color shift between the old and new Chinese AOM were the same 

[Dave S]

16 minutes ago, Qssoperator said:

@Dave SIn facts, before replacing the old original AOM with the new Chinese AOM, the green tone appears 1 to 2 prints a day and sometimes doesn’t appear. Afterwards, when the Chinese made AOM was installed, the green tone appeared more than the old AOM and more occasionally during the first 4 hours of production. After that doesn’t appear until the closing time.

 

16 minutes ago, Qssoperator said:

@Dave SIn facts, before replacing the old original AOM with the new Chinese AOM, the green tone appears 1 to 2 prints a day and sometimes doesn’t appear. Afterwards, when the Chinese made AOM was installed, the green tone appeared more than the old AOM and more occasionally during the first 4 hours of production. After that doesn’t appear until the closing time.

It is more difficult to identify when the problem is intermittent.
It could be either the problem with laser head is getting worse, or simply the replacement AOM is bad.

Both the AOM's and lasers are sensitive to temperature changes.

If it was less bad with the original AOM driver, try putting it back in, if the problem now appears less as in 1-2 prints a day, you'll know the issue is bad Chinese AOM's.
If not it's probably the laser head.

[PHOTOLABPART.COM]

Respected Sir 

 

Please check aom and Laser control connectors properly fix or not...

There is any error? 

 

[kodak_service]

If the color does not change dramatically within one photo, then 90% of the time the problem is in the green gun.

[alexvigor]

9 hours ago, Qssoperator said:

@Dave SIn facts, before replacing the old original AOM with the new Chinese AOM, the green tone appears 1 to 2 prints a day and sometimes doesn’t appear. Afterwards, when the Chinese made AOM was installed, the green tone appeared more than the old AOM and more occasionally during the first 4 hours of production. After that doesn’t appear until the closing time.

It all looks like G laser gun is dying slowly. If I were you, i'd start to prepare mentally for it's replacement. But need to exlude all other problems with wiring and heating not to waste money. Check AOM-driver section cooling fan. Also clean laser section cooling manifold (located under laser section right above paper magazine B), it has 2 cooling turbine fans, that are most likely clogged. 

[Qssoperator]

I would like to update about the intermittent green tone. The AC is chilling directly blowing into the printer top cover and upon changing the direction of the Blowing cold air, it’s hard to believe that the intermittent green tone doesn’t appear. Could someone explain if this was the cause of the problem or just a coincidence? 

[yustas]

Overheating can often be a cause of the issues with the minilab.
In the manual, you can find:

"
To avoid basic causes of screen errors, always follow the installation requirements:
- The machines should be used in places with a relative humidity of 30 to 75% and an ambient temperature of 18 to 20° C. Otherwise, use an air conditioning system.
- Do not install the machine in a very dusty or highly vibrating place.
- Do not raise or lower the room temperature suddenly. If you do this, moisture in the air can condense on the machine, causing the laser guns to fog up, malfunctioning electronics and circuit boards, etc."

Now you should watch for a change in color. 
If the AOM driver or module is faulty, the color change will occur again in any case.
If cooling has brought the exposure unit back to normal operation, you're in luck—just make sure to maintain the proper temperature settings.

[Dave S]

5 hours ago, Qssoperator said:

I would like to update about the intermittent green tone. The AC is chilling directly blowing into the printer top cover and upon changing the direction of the Blowing cold air, it’s hard to believe that the intermittent green tone doesn’t appear. Could someone explain if this was the cause of the problem or just a coincidence? 

Both the lasers and AOM drivers are sensitive to temperature changes.

The machine generally likes the same temperatures that we do.
18°C to 20°C is the ideal.

[alexvigor]

6 hours ago, Qssoperator said:

I would like to update about the intermittent green tone. The AC is chilling directly blowing into the printer top cover and upon changing the direction of the Blowing cold air, it’s hard to believe that the intermittent green tone doesn’t appear. Could someone explain if this was the cause of the problem or just a coincidence? 

Have you checked laser section cooling manifold and fans, as previously advised? 

Fixing the cooling issue can give you some time, but still temperature sensivity is another symptom of degrading laser gun. I had very exact issue recently with green gun on qss32.

Edited May 10 by alexvigor

[Qssoperator]

“Cross fingers”, Hopefully not coming back. Thank you for all your advice 
——

@alexvigoryes all was checked and cleaned the exhaust manifold beneath the laser unit. 

[Qssoperator]

Hello to all of you, I would like to update you regarding my recent experience with my Qss37HD. For more than a month of disappearing in the erratic green tone, it appears again and sometimes erratic green tone and sometimes erratic magenta tone. So is it time to replace the green laser module? Or is there another reason why this erratic color change, please advise. Thank you 

[yustas]

If this happened suddenly, in 99% of cases the cause is a faulty AOM driver.
Your 37 model (regular version, not G)  has only one AOM driver.
The G version does not have AOM drivers at all because all lasers there are directly modulated.

Edited June 22 by yustas

[alexvigor]

38 minutes ago, Qssoperator said:

Hello to all of you, I would like to update you regarding my recent experience with my Qss37HD. For more than a month of disappearing in the erratic green tone, it appears again and sometimes erratic green tone and sometimes erratic magenta tone. So is it time to replace the green laser module? Or is there another reason why this erratic color change, please advise. Thank you 

I'd suggest to start to diagnose this issue from scratch. The AOM -driver is a kind of lottery. It can last both for days and decade.

Start with AOM-driver replacement. 

[Qssoperator]

@alexvigor, I have changed the AOM from the start of having this erratic green tone but it is made in China. Later on, I put it back the old AOM and it works for a month but now it is not only erratic green tone but erratic magenta tone as well. I’m quite confused now which one is defective, green laser module or AOM

[alexvigor]

It is quite possible that you have both aoms defective. Try another one.