how to fix pantograph for Spectrum Acela

[ericw95]

Hey guys, I'm kinda new here. I was just wondering if anybody knows how to replace the pantographs on the acela as one of them is missing the clip to keep them down. I ordered the ones from bachmann's website and there are no instructions on how to install. It appears that they are screwed in internally, but I cannot figure out how to open the body. Thanks for any help