Macbook pro troubleshooting - please help!

[luxmac]

I have a macbook pro 7,1. What happened is this:
- Suddenly turned itself off.
- Upon turning on again, fan spins at max rpm, otherwise seemed to boot up normally. While booting it produced an unpleasant burning smell, so I turned it off again.
- Campus technician did SMC reset and ran diagnostics. If I remember correctly, it indicated no battery found, no temp sensor found and no fan found.
- Despite these messages, it did run off the battery and the fan did work (constantly at max rpm). It didn't charge though.
- Superficial inspection (battery and bottom side of logic board) reveal no apparent signs of anything being damaged or molten.

There was no liquid spill or anything of that sort. I did occasionally get a 'battery needs servicing' message, which usually disappeared by itself. The battery was quite worn. A full battery gave +/- an hour of life under normal load.

Is this combination of symptoms common? What i'd like to know is whether it's worth trying to replace just the battery. But the sensor and fan errors suggest that it will take more than that. The campus technician said that when sending it in for repair, it would probably be a battery + logic board replacement.

Any insight or similar experience is appreciated!

 

[duervo]

I agree with the campus tech.

There's not much choice.

You can either live with the temperature sensor not working, and as a result, fans running at max RPM until they pretty much give out earlier than they probably would have under normal conditions, or you can get it fixed.

BTW, I'm not trying to be "clever" here ... Some people are actually ok with the constant sound of the fans running at max RPM. (I wouldn't be, though. Bugs me too much.)

At any rate, I'd at a minimum at least get a new battery. Keeping the one you have is just asking for more trouble down the road.

 

[luxmac]

BTW, I'm not trying to be "clever" here ...

Oh don't worry, it's sound advice and I would do it immediately if it weren't for the cost associated with such a repair, or buying a new one, which I guess makes more sense.

Maybe I can clarify my question: is the sensor issue perhaps a side effect of a bad battery, so that this issue will disappear once I put in a new battery?

And can the sensor be replaced?

Why does a bad battery cause the sensor/fan to become defective anyway?

Just want to have some answers to these questions before I decide what I'll do.