too late at night, yup microchip logo don't know why I said motorola
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Thanks for the informations everyone.
Makes sense to be some kind of custom micro as all the furnace sensors are connecting back to it through some signal conditionning. Something in here needs to control the sequence of operation for furnace ignition and there is not much aside from a lot of passives components.
That being said that's not great for my chance at repairing this thing. I'll doube check for cold joints and verify all passives again tonight. Otherwise I see some of those board that were removed from functioning furnace on ebay are realtively cheap. I guess I'll have to take a chance and buy one.
Thanks again