"alex goldman" wrote in message
...
wrote:

Physically broken/cracked surface mount components or the solder
connections to same. Rarely visible to the naked eye.

Is it practical to try to diagnose it further, and if so, how?

I won't bother with the phone (it's cheap), but for the laptop I couldn't
locate a replacement motherboard, and getting a completely new one is
expensive.

Is it possible to fix a motherboard if it has such problems somewhere
(broken/cracked surface mount components or the solder connections to
same)? If so, what kind of equipment, knowledge and time commitment will I
need?

It can be done, you just have to narrow down the fault to as small an area
as possible and resolder everything. I've seen this sort of problem a lot of
times with vias that go from one side of the board to the other, expansion
and flexing breaks the plating between the layers and you get an
intermittant connection with nothing visible.