So - did you draw any conclusions from your observations and measurements?
If you want to run the laser you need to do at least a crude alignment. I would not be too fussy as you can't really do productive work when it is operating like this, and I am assuming you are still in troubleshooting mode.
Further to the power supply - if your label looks like the one below ("Tested at: 32 volts") then don't change the power supply down to 30. It must be run at the voltage that it was tuned ("tested").
Thank you every one for support.
due to increase in workload i assembeld the tube. after cleaning the dust thoroughly. repairing the fans (one was jammed), doing optics alignment... the machine started consistent engraving.
Though i have to operate at low speed engraving is dark and consistent.
after couple of days completing the job, i will again put mind in tube.
regards