I have a 2006 MAcbook white. Will ALL Macbook logicboards fit and work in it?
Is there any real risk in installing a second-hand one from a reputable source?
Well there are many better placed to answer that, but it seems to me that there is a specific 'architecture' within the Macs and to change that brings with it the potential for malfunction. Like for like would be best, which will depend on you finding out which 2006 MacBook you have. Info should be available under 'about this mac' when you click on the Apple icon, top left.
There will always be a risk with 2nd hand components, but they are usually tested and guaranteed for a few months. Also make sure that you and your technician are wearing an earthing device when handling the board
In retrospect i would always get the Applecare with a new mac. I've been very fortunate not to have had any problems, others have been less so....
Finally, have you considered buying a 2nd hand replacement on eBay,(usually from someone who simply wants to upgrade) and sell yours 'as is' for all those who need parts or a project to fix ? Just a thought.
SHJ