Lotem 800 Failed Laser??

[mattdj]

Hi All

Anybody out there know how to tell if we have a failed laser on a Lotem 800V

We are experiencing lines on the plates which show up on the print

we have slowed down the drum speed which has helped

In the expose params box when we are exposing a plate it reads
Active Diodes 24 (0-23)
Factor -1

Any help would be much appreciated

Thanks in advance

 

[Kiltie]

How are you getting on with this?
If all your diodes are showing as active then they will be ok. The Lotem tests all diodes before and after every plate exposure. So the only time you'll get a blue line caused by a failing diode is when a diode fails during expose but then you get a message to "check the Plate" when the diodes are again tested after exposure.
If there is a faulty diode then you will not have the full range from 0 to 23.
From what you wrote above I'd say problem was due to bad focus or resolution out of calibration.

 

[[email protected]]

tries to run the resolution test it is like focus or laser calibration. if you use positive plate, checks the entire system load (rollers), if they are dirty, it scratches the plates and these lines can appear in print.

Good Luck,

YR

 

[PACH]

Maybe the carriage pads need oiling/carriage cleaned/ lens cleaned/ etc.

 

[mattdj]

Hi all

thanks for the reply. It sounds like it isn't a diode then!

We have changed the felt pads , oiled the V groove and the main lead screw , the only thing we haven't done is clean the lens which we will have a go at. The lines are more intense at high speed which makes me think its not a dirty lens , but will give it a go and see what happens

Any other suggestions would be welcome

Thanks for now

 

[PACH]

Hi all

thanks for the reply. It sounds like it isn't a diode then!

We have changed the felt pads , oiled the V groove and the main lead screw , the only thing we haven't done is clean the lens which we will have a go at. The lines are more intense at high speed which makes me think its not a dirty lens , but will give it a go and see what happens

Any other suggestions would be welcome

Thanks for now

Are the lines around the drum? Can you post a picture of these lines?Maybe the head needs calibrating as yvroman suggested. Send me a pm to where you are.

 

[mattdj]

Hi

Attached are 2 images showing the lines on a printed job and on a test plate.

Thanks

 

[ilker]

Ok

Pls check following steps

1. check that udrc is running (blower works and hose sucks the particules...
2. re-setup the media setup..

connect to head, if you need i can write you how to do. maybe you need to re-set laser power-drum speed- beamslope beamcurve

 

[ilker]

sometimes lens is being so dirty fyi

 

[mattdj]

Thanks just sent you a DM

 

[ilker]

Dear Mattdj,

I know this problem, but pls do following steps before you change the laserpower

clean lens
clean light dedector (just opposite of the laser head ) light dedector measure the laser beam... there is a small black glass pls clean that

lst one is re-set up the media parameters...