Can a PSU cause TEM01?

I had a K40 that I adored and used quite a bit. I had a long cut job where the tube probably got too warm and it switched to TEM01.

I decided to build a better laser out of the leftover parts. I purchased a 45W tube from lightobject a month and a half ago.

Today I finally got the point of my first test fire and the new tube appears to fire in TEM01 mode.

Can this be caused by using the same PSU in a different machine? Can anyone offer any advice? I sent lightobject an email and have not yet received a response but it is after hours. Thanks all

Is that in front of mirror 1?

Yes, this is without any mirrors or lenses.

To the best of my knowledge a PSU should not have an immediate effect on a new tubes TEM. Unless maybe the PSU is running a very high current though the tube?

Was the tube stored somewhere warm?

That’s my assumption, this fire was less than a second in duration so I don’t see how it could have damaged the tube. Still, I’m frantic.

Room tempature. It was just in my workshop. How warm is warm?

Room temp would have been fine. Not sure exactly how hot is too hot, just wanted to make sure it wasn’t stored near a source of heat like a space heater.

I don’t think a LPS would cause a mode shift. To my knowledge mode shifts are the result of changing resonator geometry. We usually see this when a tube has been overheated or very old.

You didn’t by any chance get the tubes mixed up :)?