Hello, I've been working on my Stereomour today upgrading it with the DC Filament parts. I'm at the end installing the .13 ohm resistors. While putting one of them in I had the iron on it awhile, and the resistor turned a light brown. After adjusting it to attach it to the other terminal a small piece of the ceramic fell off. I see metal but no visible signs of burning on the metal.Thanks much for any help