Dead computer

Terry wrote:
> A friend of mine wants me to look at his daughter's laptop. He says
> it won't even come on. I told them I would have a look at it, but if
> it won't come on, I don't think there is anything I will be able to
> do.
>
> Where to start?
>
>

Start with a description of the symptoms, from the owner.

You have two power sources (battery, adapter) and a
"black box" of electronics. If you don't intend opening
the unit up, then you listen to the description of the
symptoms leading up to the complete failure. If you
hear the right set of conditions, maybe the adapter
is bad, and then you find another one to test with.

Inside the laptop, there is going to be a chunk of circuitry
that handles battery charging, conversion to motherboard voltage
levels, that sort of thing. But without a schematic, it
would be pretty tough to know what you're looking at. Most
engineers and layout people, would not waste their time
labeling anything in a useful way.

I have the same kind of problem here. My stereo died, I opened
it up, and it has a whole bunch of little subassemblies. The layout
is not orderly enough to even say "this part is power", "this part is
preamp", it is just all plunked down on the main circuit board. I found
a datasheet for the main amp (a module with heatsink), so at least I know
it uses a pretty high DC voltage (and the amp part is still working). But
the mixer died, and that part is just a mess. I still haven't decided
where to start, because I really don't want to unscrew anything (no place
to lay it down while working on it, short assembly cables etc).

Paul