ILT 5500A Questions and Help

[onelightmind]

Please excuse my lack of knowledge...

I own an an ILT 5500A capable of putting out 500mw but is only putting out 100mw due to cathode sag in the beam path. It is $1500 to rebuild with the new "non sag" improved cathode. Is there a less expensive way to fix it? I was thinking of running it and using a magnet to help bend the cathode back or???? Have not been able to find a schematic on this laser so don't know much. I sent it off to the shop so I do not have it here to take apart... Thanks

[DZ]

If you can, rotate the tube 180 degrees so the cathode will start to sag the other way. I had a couple 5490's years ago and I seem to remember being able to turn those, not sure about the 5500 though.

[mixedgas]

yeah, you can try rotating the tube, but until you correct the incorrect cathode voltage, in this case too low, it will keep sagging. So you would have to rotate the tube and then once its clear, IF it clears, get the voltage back up a half a volt or so, and thats if the transformer has taps.

With that model of ILT, the main optical alignment is inside, so its a pain in the neck if you loose alignment. The cathode is AC, so a magnet is out, and DONT let anybody try to tell you to overvolt it with a car battery either.


Did you try Evergreen for a quote?

Steve

[onelightmind]

Currently the laser is here http://dzlaser.com/ I DID loose alignment and it was a super pain in my ass. Rotating the tube sounds like a great solution if it is possible. I will have to ask those guys if they can do it for me. Gotta make sure they go the full 180deg so they don't throw off the polarization on my NEOS PCOAM in my little white system...Ihave a question about my NEOS but I think I should start another thread...

I have not checked with anyone else about the rebuild. DZlaser usually does it for $2500.00 but they are giving me a break at $1500.00 for a complete rebuild which includes the tube being back to original specs 500mw min output newly desgned cathode to spread heat more evenly, regass ect. 1yr warranty 200 hr tube life at full power. They are former employees of ILT.

The laser is doing 100mw now...guess I'll shoot off an email.

[onelightmind]

"until you correct the incorrect cathode voltage, in this case too low, it will keep sagging. So you would have to rotate the tube and then once its clear, IF it clears, get the voltage back up a half a volt or so, and thats if the transformer has taps."

Please explain the low cathode voltage making the cathode sag...

The guys at DZlaser said those cathodes tended to sag due to how they were designed.

Thanks for all you guys help!!

[mixedgas]

[QUOTE=onelightmind;90900]"until you correct the incorrect cathode voltage, in this case too low, it will keep sagging. So you would have to rotate the tube and then once its clear, IF it clears, get the voltage back up a half a volt or so, and thats if the transformer has taps."

Please explain the low cathode voltage making the cathode sag...

The guys at DZlaser said those cathodes tended to sag due to how they were designed.


Tungsten gets butter soft at 700'c , then at 800'C it gets hard, and then at 1130'c where it runs, its damn tough. So the idea is to pass through the soft zone on warm up as fast as you can. Plasma cools the cathode, so if the emission is down, and the voltage is down, and the current is high, they can get weak

On some older lasers, notably lexels, the weld to the tungsten from the kovar in the lead through seal is done with a moly or nickel rod, and this can diffuse into the other metal over time, weakening it, resulting in a bend in the assembly.

Now you know the Rest of the Story ,Good Day! (RIP Paul Harvey)

Steve

[onelightmind]

Thanks for the answer. Tungsten has some interesting properties huh.

[mixedgas]

Thanks for the answer. Tungsten has some interesting properties huh.

yeah, but only half the number of phase states of plutionium. :-(

Steve

[dhg6]

I have a water cooked ilt 5500a-wl it is water cooled and capable of 1.5 watts. My trouble it starts up very easy runs for three seconds then shuts down. I have tried lowering the output all the way down from 1.5W to 200mw but it still shuts down. The curtis meter shows 250 hours. All interlocks flow sensor and thermal sensor on the tube are working and again I hve more than adaquit water flow. Does anybody in the forum have a clue what may be causing the shut down. I'm stumped. Thanks in advance.

[mixedgas]

I have a water cooked ilt 5500a-wl it is water cooled and capable of 1.5 watts. My trouble it starts up very easy runs for three seconds then shuts down. I have tried lowering the output all the way down from 1.5W to 200mw but it still shuts down. The curtis meter shows 250 hours. All interlocks flow sensor and thermal sensor on the tube are working and again I hve more than adaquit water flow. Does anybody in the forum have a clue what may be causing the shut down. I'm stumped. Thanks in advance.

On most lasers that means you have a shorted passbank transistor or rectifier.

Steve