I was trying to fix a laptop motherboard. I don't have the schematic for it.
I needed to replace some smd components that were corroded, like a capacitor.
They are the standard smd type components you would see with no markings, like the smd capacitors in the image linked to below.
http://www.capacitorlab.com/capacitor-types-ceramic-smt/ceramic.jpgIs it possible to repair and replace smd components like those capacitors without a Schematic or donor board?
I would hate to throw away a potentially fixable laptop, but I just don't know what to replace any of the components with.
You cannot identify SMD ceramic capacitors by their looks. If there are still some terminal plating left, you could measure capacitance. Voltage rating would be selected according to place it's used at or just go to max available voltage rating for the size. If cap is completely destroyed, you could try looking for similarly looking cap, preferably sitting on the same power rail and measure that.
But I don't think that is the main problem. If there is corrosion somewhere under BGA, you won't be able to fix that without special equipment.
So you think I should find a similar looking capacitor on the same power rail, remove it and then measure the capacitance?
You could also guess based on what it does. If it's decoupling on a power rail then 100n is a reasonable guess. If it's physically bulky then it may be as large as 10u.
You could look at the component the cap is near. Then check the data sheet. For example, if the cap is for a power regulator, the datasheet for the power regulator would be a good place to start.