I once made the mistake of constructing a 100x probe with a 1/2W axial resistor (10 meg, into 100k plus scope).
It worked fantastically, until the ~1.5kV peak I was measuring, jumped the poor resistor* and poofed the thick-film attenuator module in my Tek 475.
*Average 1/2W resistors are rated for about 300V, maybe 600-1000V surge.
Instead of ordering a replacement attenuator module, I hacked my own, using a few discrete resistors and a trim cap... which didn't quite work the same, having some "hook" that couldn't be adjusted out.
Meanwhile, the other channel's attenuator modules are fuzzy with tin whiskers, so the vertical gain randomly jumps up from nominal, as the machine heats up... give or take if you smack it enough times to momentarily loosen the whiskers.
So... among other reasons, I don't use my 475 much anymore... but it's good to keep on hand, just in case, anyway...
Tim