I did one once, it wasn't tricky, but I cant remember what was involved !
I believe I unclipped the chip and guide/guide holder and replaced with the copper strips, regular scx guide and holder, all of which I canabilized from another scx car IIRC.
I believe I unclipped the chip and guide/guide holder and replaced with the copper strips, regular scx guide and holder, all of which I canabilized from another scx car IIRC.