As I mentioned on RCGroups, I have several of the older (2007) VSTanks, & I have opened up & looked at one tank's controller board as well as opened up the push button style controller too, & I'm not sure what you refer to as something which you see & seem to suggest might be trimmer controls you could possibly adjust.

If you could, it might help a lot to post some photos & point out what you believe are these trimmers, because I didn't see anything when looking at my own tank.

It could possibly be the Tx buttons that have bad contact. The push button controller is very oddly done with the style pads used & the contacts on the board. If you or someone you know had another VSTank you could just try using another set of crystals & Tx to quickly diagnose if the Tx was an issue.

Maybe the forward buttons aren't working on the controller properly because the pads aren't contacting the board correctly. Also make sure the plugs are all plugged in fully inside the Tx especially the two large plugs circled.




Below are the odd contact points, the top 3 for forward motion, the bottom 2 for reverse.





~ Craig ~