trying to repair two Quantum Entertainer

[matratzki]

Hi,

I am quite sure, that both lasers were not opened before, the seal was okay and not broken.
I did not know that the crystal coating is so sensitiv. so propably it was a bad idea to open it at home whit all the dust an humidity in the air ...

I do not have the exact number in my mind, but I think there are more than 10000 hours on it (dpss driver)... I also measured the current, it would fit to a 3W Diode.
No there are no Lasorbs inside.. but with those connectors, used to connect head and driver, your are not able to touch the bare pins.
Propably I can measure the wavelenght at my university..

They used two different crystals in both lasers.. the KTP or LBO is the same only one YAG is longer than the other.. and there is a arrow on it, which is pointing to the pumpdiode in one laser and to the ktp in the other one ... a bit confusing

cheers
Mat

[dsli_jon]

Hey Mat -

..both lasers were not opened before, the seal was okay and not broken.....but with those connectors, used to connect head and driver, your are not able to touch the bare pins.

Unless you connect the head-side before you connect the PSU-side of the two-ended DB-15, iirc..
...that would leave the PSU_side with 'touchable pins'.. Not saying you did, but perhaps the previous owner may possibly-have.. just a thought..

However..

.I think there where more than 10000 hours on it (dpss driver)...

..that's a fair-amount of mileage on the diodes, I suppose they might be 'tired', but even at 10% SHG, you should be getting more than 50mW.. perhaps this is a 'combination' of contamination / temp-reg, and tired-pumps..

They used two different crystals in both lasers.. the KTP or LBO is the same only one YAG is longer than the other.. and there is a arrow on it, which is showing to the pumpdiode in one laser and to the ktp in the other one ... a bit confusing

Can you take a pic of the 'RIGHT' duh.. (diode-side) mount, there, looking 'into' it, more? Looks like, starting from the 'rear', you've got a TEC for the pump, the pump-plate, and an XY-adjustable plate, with ?? in-it.. Also, wondering if that's a Vanadate / LBO 'combo-sandwich' on the TEC in the center (?) Need moar pix..

cheers..
j

[matratzki]

Hi,
the order beginning from the right : TEC, Diode, back cavity mirror (adjustable),Crystal, LBO or KTP, lense, IR Filter
both Quantums are at home in my "laboratory" .. at the weekend I can take mooaar pictures ^^

Cheers
Mat

[dsli_jon]

Hey Mat -

.. at the weekend I can take mooaar pictures..

Cool.. I'm betting ya've got a Vanadate / KTP 'sandwich', then.. I was thinking LBO, cause it's rather 'long' for a KTP, and I have emails stating they-use LBO vs KTP, but.. I guess, re-reading them, they might have been talking about the Elites.. so, I suppose the Entertainers could-be YVO4 + KTP, but.. in any-case, I do-also think 70˚C sounds high.. I know the 'trip-out' thermals for the case was only 45˚C, but not sure how 'far away' they have the thermistor for that, so... ??? That's where the 'P'Fesser' comes-in.. (mixedgas / Steve..)

..look-forward to more pix..
cheers..
j

[mixedgas]

My best guess.

YAG/VANDATE, a little above specified operating room temp, ie 5-10 'C to actually cooled. KTP, very Hot. LBO very warm.

They can, of course, order the crystals for other cooling/heating schemes. The classic one is what I describe above.

If you have two heads and two drivers you can backcheck this.

I assume you have the factory cables and the thermisters are thus hooked up?



Steve

[dsli_jon]

I assume you have the factory cables and the thermisters are thus hooked up?

Very-good point.. We still have one of the OEM DB-15s for these kickin around in NY, but I don't remember if they were 'cross-over' / custom-wired, or, just 'DB-15, straight'.. most-likely, were, but.. certainly worth a double-check, Mat...

j

[matratzki]

Hi,
so I checked both heads and drivers.. all thermistors are hooked up and the the temperature changes when I turn the temperature trimmer.
Yesterday I adjusted the second head and this one has a actual outputpower of 70mW and a better beam than before (after adjusting the cavity). At both heads the Temp of the laser crystal is set to 74°C..
I also cecked the crystals of one laser with a microskop... all coatings look perfect.
So here are more pictures..

Mathias

[chad]

I can't believe how crappy all of the machining is in those things.

Chad

[steve-o]

Kinda rough.. but neat from a hobbyist's perspective How much power are those supposed to be putting out ?

[matratzki]

They should put out 600mW ;/