COMMON ERROR IN LASER UNIT

Permanent “Laser Temperature is being adjusted”:

This stage is important to let laser guns reach stable working parameters. The basic parameter is temperature. All others are secondary. If this message never goes away, it’s probably because laser unit is not properly installed. Some of wire connectors were disregarded or damaged.

There are four connectors for Laser Temperature management. Two for RED and two for deck. Each pair consists from one thermosensor (up to 10 KOm depending of temperature) and heaters (15 Ohm on the bottom of laser unit, 0,3 Ohm for RED laser). You can check those yourself with ease. If hardware is fine but still giving error, you might need to clean both fans under the laser unit or check ambient temperature. No Laser repair required.

However if you get this error sporadically while working, usually it is accompanied by other errors or affects on the prints. You have to report entire list of problems. Laser repair may be required.

6073 Syncronouos error:

• 6073-0001: RED laser syncro signal could not be read. Possibly RED AOM Driver is defective.
• 6073-0002: GREEN laser syncro signal could not be read. Possibly GREEN AOM Driver or GREEN Laser driver are defective, or GREEN Laser Driver is not powered on.
• 6073-0003: BLUE laser syncro signal could not be read. Possibly BLUE AOM Driver or BLUE laser Driver are defective, or BLUE Laser Driver is not powered on.

This error is generated when there is no beam on the exit synchrosensor, or the beam is very weak or unstable, and sensor couldn’t detect its stability. There are many reasons why this error could have appeared. The most likely causes are the contacts and connectors. Check all the cables going between Laser Unit and overall electronics. Be sure that all the contacts inside the connectors are well-contacted, clean the contacts, move connectors up and down to best fit. Inspect AOM Driver according error codes above and all the cables and connectors related. You can swap AOM drivers and see if the code has changed. Do not forget to reconnect all the cables properly, otherwise you will get a permanent error. 6073 could also appear if the cables between Laser Unit and AOM Drivers are misplaced.

Then check the Laser Driver PCB’s. If there is no power at the Laser Driver, there is no power on the laser gun as well. Therefore, there is no signal on synchrosensor. If you are sure that the general power is ok, but swapping laser drivers give you code change, this means one of your drivers is faulty. Remember? No power on the gun – no signal on synchrosensor. However… if you are not able to figure out the problem it might be because of laser unit went wrong. Thus Laser repair may be required.

Errors 6105/6106 B/G Laser Status error (B/G Laser Control Error, B/G Light Source Error):

These errors tell you exactly that there is something wrong with your laser guns. Don’t waste time to swap and check anything. Laser repair required.

Blue Laser weak:

Laser gun isn’t an Edison lamp. The emission of aged laser gun is going down slowly, sporadically flashing or changing output up and down. Laser Driver PCB follows that jumping of emission and maintains the factory preset output level by electric current (mA). Some people say why do they have to repair their units, if they are still working few hours before the error comes? They consider that problem is somewhere else. However the process of aging is a long process and can be running years and years. The very first statistic for QSS3001 minilabs shows that Laser unit must be exchanged for every two years (or 5000 hours). Than we have another experience. Some of QSS3001 even 2001 year of production is still working fine without opening a Laser Cover. Some other asked for Repair Exchange under warranty during first year of service. There are so many combination of life and dead of laser guns and units. we consider generally guns are fine for 3-4 years, then the process of aging is launched. It may takes from 3 months up to 2 years. During this period the emission of the aged gun isn’t stable and number of symptoms described in this article may appear.

Good point to review the condition of BLUE gun on QSS32-35 Series machines. Just print this Alignment pattern and look at it through a 10x lens. If you see “mountainscape” yellow line instead a straight line. Sometime the output power of Blue gun is still enough for good printing but AOM crystal generates smooth dot and scatters coherent light due to optic fatigue. Laser Unit repair is required.

“Yellow shift” problem

This is another confirmation of the same problem of weak Blue. It’s common to be seen on QSS32-35 Series laser units. For the same condition of Blue beam QSS30-31 Series machines give us Synchroerror, but sensors in 32-35’s can detect weaker beams even if loosing the right clocks. Laser repair required.

However there is at least one known exerption: please check small 4-pin digital connector on BLUE AOM driver is properly connected.

Yellow Lines

This one is the first call of optic fatigue in your AOM crystals. Yellow lines can appear just few times per day. No big worries, the small batches of prints will be thrown into the trash basket and so far that’s all. But if you disregard this symptom, “Yellow shift” problem will follow. You can try to postpone repair while putting of the brand new AOM Driver in the BLUE channel. It doesn’t mean that old one is bad, but amplifying factor of a brand new one is higher, what may temporarily help to overcome the problem. However Laser Unit repair is required.

BLUE Laser noise:

Noise is important remark that something in the laser gun’s structure has been changed badly. Usually such processes can not be turned backward. But sometime you can easily postpone repair by performing AUTOTUNING (for QSS30-31) or pressing the button RESET B/G LASER (for QSS 32-35). Note that good results which you might get after Autotuning or Laser Reset is just temporary effect. Once you may have noise never comes away. Please consider about beforehand repair of your Laser Unit.

GREEN Laser Noise:

Also remember that all Laser related electronics is very sensitive. Some of your machines are not properly grounded, and some are connected to the main which is built improperly. Old machines usually have “manual improvements” from lost screws to bulky power supplies “made on the knees”. A number of electric part inside & outside of minilab could generate the electro-magnetic fields which are able to cause the low frequency noise on the prints. Aged AOM Drivers have different amplification factors. Sometimes it is enough just to swap AOM drivers to stop the noise.

Combined symptoms:

There are many examples when the weak Blue creates a bunch of symptoms. Different combinations of shifting, noise and Error 6105 may appear unpredictably. Please note that Laser gun is going down slowly and its end of life is never stable. Output is changing sporadically and Laser Driver tunes it as long as it can. If electric current exceeds factory limit, error 6105 has appeared, if not – you can have shifting and / or noise.

You can experience the very bad results if you try to set up the minilab in such unstable condition. Below is the fragment of pattern with a multi-layered problem complicated by ultimate set up disbalance.

Polygon Mirror Control Error:

This error appears if system couldn’t stabilize Polygon rotating speed according synchro impulses generating by AOM driver. In some cases you can not print anything. But sometime it is possible to get something like on the picture below. Laser repair required unless you have found that GREEN AOM Driver wasn’t in proper condition.

Other version of the same problem is shown here:

Green Laser weak:

Green laser guns are basically much more reliable than Blue. But Greens are not eternal. The weak Green looks like your test pattern isn’t black on dark stripes and going Green, because there is lack of MAGENTA produced by GREEN laser gun. Laser repair required.

Red Laser weak:

This rare problem is going to be common on QSS 31. It looks like your test pattern isn’t black on dark stripes and going Red, because there is lack of CYAN produced by RED laser gun. Note the very-very weak cyan letter on the edge of the test pattern below. Laser repair required.

Short circuit in a coaxial cable:

These three pictures below indicate how it looks when one of coaxial cable coming from AOM Driver to Laser Unit experienced an internal short circuit. Usually it is enough just to disassemble BNC connector and fix this problem. No laser repair required.

* Courtesy of Kodak-Service, St. Petersburg, Russia.

No full sweep exposure:

Sometimes, usually after changing the laser unit you might get white prints with some greenish strokes or part of the prints are white with strokes. This is because the brackets under laser unit (QSS30 and 33) are not properly installed on the bottom of laser units. In QSS 31 the source of problem is different. In this laser the exit mirror inside the laser unit is movable. If your new laser unit has been taken from another 3101 minilab adjustment of the exit mirror position is required. No Laser repair needed.

White Border on the trail edge of paper:

After re-installing the laser, you might get white borders on the prints. This is the centering issue. The source of this is incorrect positions of the laser unit and paper advance units. When you installed them you were able to move each assembly on its pins. The resulting white edge is because those assemblies are not properly centered. But there is a basic centering adjustment by software in the service menu, where you are able to fix RED laser (cyan line) within the real center of image. Then you go to Alignment option and adjust Blue and Green lasers (yellow and magenta) according to the cyan. You don’t need to perform second step if all the colours centered perfectly. No Laser repair required.

Banding:

Sometime you can get a smooth lines accross the prints. They can have a various width, but there is a cycle, and lines appear within equal distance. This is mechanical problem of fatigue bearings and old exposure rollers. Please check exposure unit, clean and replace parts if needed. No Laser repair required.

Fatal Error Laser:

You might consider that this is the end of your business and all your creditors will arrive to kill you. Relax! Service Manual suggests… just to reinstall main Software.

We will be glad to add more pictures and advices on this page. Thus please e-mail us your scans and explanations, we will consider to add new information to this summary. Thank you for further participation.