Some of those are pretty cheap, so it may not be worth it, but I got a couple repaired at the last Thai hardware shop on the west side of Phetkasem Rd. a bit before the Palace I think... (sorry, best description I can give). They sell a lot of brands and types of pumps and power tools and they repair them both.
My brain is like an Internet browser; 12 tabs are open and 5 of them are not responding, there's a GIF playing in an endless loop,... and where is that annoying music coming from?