I always try to have a cheap spare part that I know is working handy, ie Ram and Video card. CPUs and motherboards a bit more $$$ but an older Ryzen 1500 and a used/open box AM4 motherboard can be had for very cheap and can be resold for minimal loss once you're done troubleshooting.
This ASRock B450 has some "used" options available less than $60:
Ryzen 1200 for similar price, less than $60:
Asus Prime Z370, Intel 8700k @5.0Ghz, Nvidia GTX 1080 Ti, 16GB @3400 CL14, Watercooling: x2 MCP355 pumps, x1 280 on front of case, x1 360 on top of case, x1 140 on back of case, x1 240 on bottom of case
Last edited by StAndrew; 02-21-2020 at 11:01 AM.