ebay could get you a motherboard for a lot less. You are sure it isn't the fan? It sounds like you have more of an idea than I would. My only suggestion is for sources for a used tc1100 for parts- you can pick one up under $100 at ebay if you are patient, and currently there are some tc4200 and 4400 from bargain_chain in florida that are available-- this company did well when the unit they sent first had a problem, they shipped out an exchange! This just this week and upgraded me from a 4200 to a 4400! They are out of florida and my experience was a good one.