ILT 5500A Questions and Help

[dhg6]

Just a little update of the tube output. I could only get it down to 500mw and it's still bright as the sun. My camera was in fireworks mode as it was to bright in any other setting. I shot it into some diffraction grating but didn't have a tripod so it's a little blurry but very stron green and blue lines. Now we can work on getting the board working correctly instead of bypassing operatory inputs.

[Stoney3K]

Just a little update of the tube output. I could only get it down to 500mw and it's still bright as the sun. My camera was in fireworks mode as it was to bright in any other setting. I shot it into some diffraction grating but didn't have a tripod so it's a little blurry but very stron green and blue lines. Now we can work on getting the board working correctly instead of bypassing operatory inputs.

Looks great! So you have no trouble to run the tube in CW for longer periods of time anymore?

Can you post some measurements on the tube (e.g. cathode AC voltage, tube DC voltage, tube current) at different power levels so we can get a general idea on its condition?

[dhg6]

Yes I built a recirculation unit with an ice bath. The thermal cutouts still work because until I put my ice bottle in, it got hot and shut down so the board isn't completely bypassed. After I put my ice bottle in no more shut downs and the water on the exit line comes out warm but not hot like it did before I put my larger volume pump in and Ice. I will build a real chiller when I get the unit repaired correctly but it has no problem running continuous duty. Can you measure the tube without frying a digital multimeter? As long as you use the banana Jacks on the side panel? I don't want to fry my meter.. The jacks are laser power (blue jacks), cathode voltage (green jacks), and Anode current (violet jacks).

[Stoney3K]

Can you measure the tube without frying a digital multimeter? As long as you use the banana Jacks on the side panel? I don't want to fry my meter.. The jacks are laser power (blue jacks), cathode voltage (green jacks), and Anode current (violet jacks).

You can use the jacks without any risk to your meter (see the manual).

The tube voltage can be read from the leftmost anode current jack together with the leftmost cathode voltage jack, and it reads DCV directly. Make sure you use the proper range (around 250V).

Take care to connect the meters only after start, since I'm not 100% sure if they're HF decoupled, so some high voltage from the starter may bleed through.

[mixedgas]

You know a tube like this normally gets a minimum of 2 gallons per minute through a garden hose, right?
You need to get rid of up to 7 Kilowatts, and if the thermals are tripping, your very short of coolant.
Ice baths dont last for long, and the huge thermal gradients are hard on the tube.

Also watch your anode temperature, that fan cooled anode is a weak spot.

Steve

[Stoney3K]

You know a tube like this normally gets a minimum of 2 gallons per minute through a garden hose, right?
You need to get rid of up to 7 Kilowatts, and if the thermals are tripping, your very short of coolant.
Ice baths dont last for long, and the huge thermal gradients are hard on the tube.

Agreed. If you only run it for short periods, just hook up a garden hose from the wall and dump the waste water down the drain. It won't ever run out of cold water and you're not going to have any problem with cooling like that. I cooled a SP168 from the wall and the water on the drain line was only hand warm, so you'll have plenty of cooling headroom. Not recommended for long runs, unless you have a deep pocket and don't care about your water bill

7kW might be a bit optimistic though, since the 5400 series PSU's have a 20A fast blow fuse on 230V single phase, so you'll only be able to pull 4,6kW from the grid.

[dhg6]

Ok the tube voltage when I first started was at 207.8 vdc. after warm-up it stabilized at 148vdc. respectively. Cathode voltage was at 3.1vac (seems resonable). I don’t know if the 5500 manual is the same as it is for this unit. It dictates 10 millivots=1 amp for dc for anode current. I measured 9.5 millivolts that would make it drawing less than an amp. That can’t be right.

[dhg6]

This unit has 1/4 " tubing and I'm on a well so I don't even want to run well water through it. I do have two type of filters installed in my home, one to remove minerals and the other is a no salt softener. I am currently using a 10 gallon recirculator with distilled water. My ice bath works perfect and it's using a custom fitted 1/4 hp 1500gph pump It has better flow than any home tap. It's restricted not to push more tha 40 psi. water is warm to the touch on the return line. I am going to build a chiller coil when I fix this thing correctly.

[Stoney3K]

Ok the tube voltage when I first started was at 207.8 vdc. after warm-up it stabilized at 148vdc. respectively.

That sounds like too much of a drop. 207.8V is good, but 148VDC is just not right for a 5500 tube.

It sounds like your power supply can't deliver enough juice to keep up the amount of current this thing needs (it would also explain the low current reading). What are the readings with the power control on minimum setting?

[dhg6]

took readings again. tube is definately at 148vdc. power is at 8.3vdc book says 1 milliwatt=.05vdc I'm at 1.6 watts of power. the anode current measured 132mv. my meter must have flipped out the first time iI took it. it's at a 132mv = 13.2 amps according to the book. Is their a pot on the light card or board of the head that lets you adjust tube voltage. here is a b picture of three pots and a side view.