Knocking Sound from Your GE CT Scanner? Check Your Encoder Wheel!

So, you're running your GE CT and you start hearing a rattle, a jitter, or a knock. It never made that sound before, and you're pretty sure it shouldn't make that sound at all. Why is it doing that?

With so many moving parts, there are a few things that can create a similar sound inside the gantry of a GE CT scanner, however, one of the most common for is the axial encoder. Keep reading to learn what you should do to solve the problem.

The Nature of the Problem

The sound that you hear from an axial encoder assembly is caused when the plastic material that makes up the sprocket begins to deform. Because the gantry returns to the same axial position each time it stops, the deformation is most likely to develop at that spot. As the deformation increases, the wheel begins to "hop" more and more and can, eventually, skip counts. The hopping creates the knocking sound when the metal of the assembly's moving bracket strikes the fixed bracket. You can see the encoder assembly bouncing when the left side cover is off. 

The Solution

The best thing to do when you begin to hear your encoder assembly knocking is to schedule its replacement at your next convenience. As time and use go on, the deformation of the sprocket will only worsen. If for some reason you need to put off replacement, you do have some time before this issue will put your system down completely, but if you can stay ahead of downtime, we suggest you do so.

Currently, this is what you can expect to pay for a replacement axial encoder assembly (p/n 5182284-2):

New: $2,300

Used: $950

The Next Step

If you've heard encoder replacement knocking at your door (See what I did there?) you'll need two things to answer: a replacement encoder assembly and a field service engineer to install it. Fortunately, we can help you with both of those things. Use the buttons below to reach out to our Parts Team or our Service Team and tell us how we can help.