I am working on a GE Lightspeed 4.X, and I can't get it to properly work. Every time I fire a shot at 300mA, it gives me an error of Cathode Shoot-Thru. I have replaced both HV tanks, both inverters, the tube, the HV cables, and the filament board in the OBC. There is also a sound that comes from the gantry whenever an exposure is made, and it almost sounds like aring, but weaker.I can't figure out what the problem is.
What's the Cathode mA value at 300mA? Run kV/mA verification Test
Since the cathode is in series with the anode, anode mA should be the same as cathode mA.
If cathode and anode mA are different, suspect mA measurement electronics (use mA Meter Test), or suspect a shattered x-ray tube insert shorting out the filament (cathode) or the anode.
We've attempted to replace the mA Control Bd, and the tube has been tested off the system and is fine. I will try to measure the mA with the meter test and watch for a difference in the Cathode and Anode mA values. Let me know if you have any other ideas
Hello, I assume it happens at 300 ma or higher. I had this exact event years ago and found that someone had serviced the slip ring brushes. They had pulled the brushes and turned them so that the wear angle was backwards reducing surface contact.
I will take a look the next chance I get, but I donât think it could be the Brushes, since this system was deinstalled working and arrived at our facility not working. Thanks for the tip though.
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KeeganLampley
GE Lightspeed 4.X Cathode Shoot-Thru
March 30, 2018 10:01
I am working on a GE Lightspeed 4.X, and I can't get it to properly work. Every time I fire a shot at 300mA, it gives me an error of Cathode Shoot-Thru. I have replaced both HV tanks, both inverters, the tube, the HV cables, and the filament board in the OBC. There is also a sound that comes from the gantry whenever an exposure is made, and it almost sounds like aring, but weaker.I can't figure out what the problem is.
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CRAIG WAMBURA
re: GE Lightspeed 4.X Cathode Shoot-Thru
March 30, 2018 05:43
What's the Cathode mA value at 300mA? Run kV/mA verification Test
Since the cathode is in series with the anode, anode mA should be the same as cathode mA.
If cathode and anode mA are different, suspect mA measurement electronics (use mA Meter Test), or suspect a shattered x-ray tube insert shorting out the filament (cathode) or the anode.
I would suspect the mA Control Board
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KeeganLampley
re: re: GE Lightspeed 4.X Cathode Shoot-Thru
April 02, 2018 09:44
We've attempted to replace the mA Control Bd, and the tube has been tested off the system and is fine. I will try to measure the mA with the meter test and watch for a difference in the Cathode and Anode mA values. Let me know if you have any other ideas
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Nathan PARRIS
re: GE Lightspeed 4.X Cathode Shoot-Thru
March 31, 2018 02:45
Hello, I assume it happens at 300 ma or higher. I had this exact event years ago and found that someone had serviced the slip ring brushes. They had pulled the brushes and turned them so that the wear angle was backwards reducing surface contact.
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CRAIG WAMBURA
re: re: GE Lightspeed 4.X Cathode Shoot-Thru
April 02, 2018 09:41
ooh I completely agree
It maybe the power supply to the rotational frame is not perfect.
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Keegan Lampley
re: re: GE Lightspeed 4.X Cathode Shoot-Thru
April 03, 2018 09:43
I will take a look the next chance I get, but I donât think it could be the Brushes, since this system was deinstalled working and arrived at our facility not working. Thanks for the tip though.
to rate and post a comment