I started my 1986 Volvo 240 with the electric speedo up a while ago and let it idle for about 30 secs and soon noticed an increasing amount of white smoke coming out through the guage cluster. I shut it off immediately and it stopped burning and it hasn't started smoking since then, but the speedometer and odometer are both completely non-functional. Does anyone have any idea what a possible cause is and what I could do to fix this and get the speedo working? Is a replacement the only option and if so, where do I find one? An interesting side note is that the formerly non-function gas and temp guages actually started working after this fire or short.