YAG flow tube cleaning...

[uk-laser]

My little lamp pumped 532 is only putting out 2.2W instead of a rated 3+.
I have replaced the coolant and DI pack but looking closely at the water tubing from the head I have found a fine black (or brown) precipitate coating the inside of the pipes.
This appears to be system wide although I have not opened up the head yet to confirm.
Is there any non-invasive way (ie a flush) to remove it?
I am keen to see if this is what is reducing the output power or if it is the lamp which is end of life.
I am wary of just opening up the head because apparently the Alcons are a pig to align but I am equally reluctant to just flush it with hypochlorite without knowing compatibility of metalwork and seals in the coolant circuit.

Cheers,
Robin.

[Laserman532]

My little lamp pumped 532 is only putting out 2.2W instead of a rated 3+.
I have replaced the coolant and DI pack but looking closely at the water tubing from the head I have found a fine black (or brown) precipitate coating the inside of the pipes.
This appears to be system wide although I have not opened up the head yet to confirm.
Is there any non-invasive way (ie a flush) to remove it?
I am keen to see if this is what is reducing the output power or if it is the lamp which is end of life.
I am wary of just opening up the head because apparently the Alcons are a pig to align but I am equally reluctant to just flush it with hypochlorite without knowing compatibility of metalwork and seals in the coolant circuit.

Cheers,
Robin.

google - oakite 33. This is what we used to clean PT's with severe deposits.

[uk-laser]

google - oakite 33. This is what we used to clean PT's with severe deposits.

Thanks for the pointer.

Hell! That stuff is 50 to 60% phosphoric acid
The remainder seems to be a mix of organic solvent and a surfactant.
(the surfactant is cited as being a xenoestrogen precursor)

MSDS calls for safety goggles and a face shield. Don't know if I would be more woried about the risk of severe burns or growing breasts....

[Laserman532]

no worries mate...my third eye will be watching your progress!

[soforene]

...my third eye will be watching your progress...

Speak for yaself.
I'll be monitoring the Boobcam.

[gogu]

How about changing the lamp before you flush anything through the system. Quick power reading.
If its not the lamp, you can always swap it back, or place it on a shelf for later use.
while you have it open, check the mirrors/q-switch for burn marks?
Tried different water temperatures? (increase and decrease the water temp by 1deg C +/-, i've seen this increase power.)
Check the beam profile? nice round, full mode?
imho if all of the above fail, i would try aligning, before putting any chemicals in the system.
Seen a system that never had a water change, di resin or particle filter changed in 10 years, and after aligning it output same as the day it was built.

Cheers

[uk-laser]

Thanks for the pointers.
Unfortunately I don't have a spare lamp.
The service manual gives a lamp spec of 99 to 109V, 20A but does not give a bore diameter or arc length. Guess I will have to open it up some time soon to find out.
I'm just reluctant to pull the lamp as it will involve removing the cavity from the optical plate, resulting in a realignment when I drop it back in.
*Here is where I admit I have never aligned a lamp pumped YAG before*
The beam bounces through some shutters and a servo controlled mirror before being fired into a 200u fibre. If I work up some courage I might try to peak the output - just worried it might throw the landing into the fibre out.
I'm fairly sure the residue is causing some power drop off though. It is noticeably darkening all the clear water tubing.
The water cooler is not closed loop. There is just a water to air exchanger and a fan.
The beam profile looks OK.

Hopefully I'll get some time this weekend to investigate...

Cheers,
Robin

[Laserman532]

does it have a di cartridge? did the power drop off quickly or slowly, how many hours on the lamp? VARIABLES and More VARIABLES

flush and refill first - might help

[uk-laser]

I did find a nylon bag of DI resin in the back corner of the water reservoir.
I guess this is the one which was shipped with the unit when new.
The chap I bought it from got it second hand but he had it serviced whilst he owned it.
Unknown hours on the lamp.
Will try a neat water flush first then perhaps move to something stronger if that fails to do anything.

[gogu]

Lamp pumped systems as far as i know, need the lamp replaced between 300-1200 hrs, decreased power is a sign.
Perhaps some residue on the inside of the cavity? Got a picture or a diagram of the inside, perhaps something in the manual or the web if it hasn't been opened?
What's the make/model of the laser?
Check this link out for quite a few different cavity designs, (its about 5.5MB) might find the correct information you're lookin for in regard to the lamp.
http://www.directedlight.com/pdfs/DLICATALOG.pdf