Zoom out switch glitching, not a lens issue, need help to repair.

[raffivegas]

Hi there, not sure what terms to search for, almost all of my searches are giving me results regarding the lens motor.  My a5k which has seen light use over the years has developed an issue with the zoom in/out rocker which sits around the 'snap picture' button.  Sorry, I'm a layman and don't know what the correct terms are for these things.

When previewing an image, if I flick the rocker to the right, it zooms into the picture all the way.  Now I have to start backing out to see what I want to see.  As I flick or hold the rocker to the left (marked W on the camera body), the preview starts to zoom out but then will glitch out and zoom back in and out and in and out and it will get 'stuck' in this pattern until it eventually, jerkingly, zooms all the way out of the preview.  This behavior occurs when using the rocker to zoom out the lens, but if I use the zoom control on the lens itself, it works fine, so I know its an issue with the rocker which sits around the 'take pic' button.  

Has anyone experienced this before?  Can you suggest some better search terms?  I usually repair my own gadgets and wouldn't mind taking this one on, just not sure where to start.  Seems like I'd need to purchase a donor camera to get the parts off of.

Thoughts appreciated, thanks.

Edited December 16, 2019 by raffivegas
grammar, formatting