You have the "RED BLUES", the tube is very high pressure and must be ran for a few hours a day. Krypton is pressure sensitive, and when the pressure builds the yellow and green lines stop working. This leaves the two very high gain lines, 647 and 488, to lase. The O-ring seal in the refill system leaks very slowly over time.
Pressure has built up in the tube.
Spend time retuning and cleaning the optics to be sure. Is the magnet working and set at the correct field?
Do not leave it on the shelf at this point, unless you wish to ship it to Germany for re-pumping.
Steve
Qui habet Christos, habet Vitam!
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When I still could have...