I obtained a used Garmin Zumo 450 when I bought a used R1200RT 6 weeks ago.
It sorta worked, but I had to frequently re-calibrate the screen. It locked up and also did not want to be programmed for finding new locations. I thought restoring factory settings might solve the problem, but that caused the entire GPS to stop functioning. None of the ways described in the owners manual would help get it working. Garmin no longer provides service for this model that cost $800 when new 7 years ago.
So I went on line and found a repair ad from palmdr.com I emailed from the website and asked if I could stop at to their location in Mankato, Minnesota since I would be traveling that way for the rally in Saint Paul. I also described the problems I was having with the Zumo 450.
Chris Short, President of Short Tronics aka palmdr.com answered me within a couple hours. He told me when the shop was open, estimated it would take 20 minutes to fix the 450, and quoted a price to fix the unit.
I arrived there at 4 PM on Tuesday before the rally and he checked it out, replaced the touch screen within 10 minutes and started testing my unit. We found the previous owner had only loaded Eastern USA maps, which would not give me a route to the rally as a test. At my request, Chris loaded up to date maps for North America. Maps usually take a while to load. Everything was done in about 35 minutes, including some great conversation.
I have used the unit repeatedly since this repair and it works like new! Cost was $61,10 (including tax) for the repairs and map update.
I highly recommend this company for repairing Garmin GPS units. Most of the business they do is from GPS or other gear shipped to them.