Hi everyone, It's been a while¡
Thanks to your suggestions, I fixed the sticking buttons on my (US) Xpander by filing the edges of the button holes to make them a bit wider.? (In fact, the holes look nicer now that they don't have ages of crud stuck to the sides. :P)
I believe that the original cause of the sticky buttons is that the thick plastic sheet covering the front panel shrinks over time.? As the plastic shrinks evenly, it tightens towards the center of the panel.? On my Xpander,? _every_ button hole was shifted towards the center by a few millimeters, making the holes tighter against the sides of the buttons that face away from the center.? To re-widen the holes, it only takes a bit of filing the plastic cover where it had intruded on the hole.
If you¡¯re up for it, a few bits of advice¡? Mostly common knowledge to anyone who¡¯s done this type of work, but just in case:
-You¡¯ll need to open and dissemble large parts of your Xpander.? Do not attempt this if you are uncomfortable, or if you don't have the patience to go slowly and safely.? This operation doesn¡¯t involve any electronics trickery, just a steady head and hand.
-Before you disassemble anything, be sure to take careful notes on which side of each hole needs to be ¡®expanded¡¯.? :)? Once everything¡¯s apart, it¡¯s easy to forget where your trouble spots are.? I did this by marking these spots on the front panel with small pieces of painters¡¯ tape, and taking copious pictures.? The only way to test your work is re-assembling everything, since the buttons only line up very precisely when screwed all the way back in, so get it right the first time! ? These covers will keep shrinking as they age, so also consider areas that aren¡¯t a problem _yet_ but look tight.?
-Unscrew the cover from its hinges.? This is to keep loose filings away from the Voice and Power boards.
-Remove the volume and encoder knobs from the front panel. (First, pop off knob caps and loosen the interior screws.)
-Remove the Processor board and the the Pot board.? The Display board can stay attached to the Pot board.? Lot¡¯s of screws to remove.? Again, take pictures to get it all back in later.? Take care to only remove the screws needed to remove the entire board.
-Be _extremely_ careful when removing these large boards.? The I/O jacks on the Pot board can get stuck as you tilt it out, and could bend or break something.? The Display board holds the famously-difficult-to-replace VFDs.? These boards are all fragile, and will need a nice soft place to reside while you¡¯re working.
-Filing is the easiest part of the operation.? I used a set of small metal filers from the hardware store.? There were a few grades of tooth.? Use thick tooth first, then more refined ones.? I actually filed around all of the holes a bit to clean them, looks way better.
I think that¡¯s it.? I hope this info is helpful to someone, and thanks again for the advice.
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r1n9o