Identify unknown disc-shaped component - markings include VF10 0471K
VF10 matches a type of varistor which is 10mm in diameter, as you reported, and is sold by some companies. For example here is a datasheet which includes a VF10 series made by AVX.

It has the "UL Recognised" logo (a "backwards UR") at the start of the second line.

0471 matches a nominal voltage of 470V (e.g. 1mA nominal current at this voltage).

K means ±10% tolerance, as usual (see the order code part of the datasheet below for confirmation).







Image source: AVX datasheet, Zinc Oxide Varistors, VE/VF Types for Heavy Duty Applications (“P Series”), pages 3 &amp; 12

It's interesting to see the different voltage ratings shown, depending on the varistor type:


the VE series component markings indicate the "maximum operating voltage" (Vrms), 300V in this case, so the marking is 301
whereas the VF series component markings indicate the "nominal voltage at 1 mA DC" (V1mA&nbsp;nominal), 470V in this case, so the marking is 471.


This article explains that a 470V varistor (i.e. a 300V RMS continuous operating voltage rating) used across a mains supply input, is intended for a mains voltage no higher than 220V. If your varistor was connected across the mains input, and the product was connected to a higher mains voltage, that might cause premature failure.

I have used MOVs in the past, which were that same light-brown colour (although, as commented, blue is a common varistor colour).

What I can't do is match every part of the markings on that device e.g. the initial leaning "T"(?) - perhaps a manufacturer's marking.

My conclusion is that because of the points above, this yours is a VF10 470V varistor but not made by AVX, so it will likely not exactly match the VF10 specification in the AVX datasheet linked above in every way.