Max, the OP is in the USA, the newer TE system has been available here for many years.
If you are alluding to another system for remote control, there are tons of options here in the US, I would recommend the G Scale Graphics products for low cost, simple control, likewise located in the USA.
Greg
ThanksSorry, highly doubtful you can repair it, other than looking and seeing any obvious damage, have not seen one on ebay for a long time.
No schematics I have ever come across.
Greg