Mac Mini SMC button on logic board was hit multiple times

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Mac Mini SMC button on logic board was hit multiple times

Just for kicks I am trying to hack my MacMini2,1's internals into an old Blue & White G3 tower. I noticed the SMC reset button on the logic board but didn't realize that hitting it while off would do anything. Well, owing to a bad design of my new setup, I have pressed the SMC reset button at least several times trying to get it put in there. This may have also happened while the power was connected.

Now, the Mac Mini just starts on its own when power is applied from a power strip, and each time the date/time info is erased. It didn't used to due this when turning on the power strip. This happens with or w/o a CMOS battery installed. I have checked the CMOS, it seems good. I have tried zapping PRAM,

Also, after the regular startup chime ends, I can hear the end of an another chime that apparently except for the very end is being interrupted by the current chime. Any ideas? Thanks in advance for any help.

Mac mini, Mac OS X (10.6.8)

Posted on Mar 22, 2014 7:29 AM

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Answer 1

Bill3Smith Author

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Mar 22, 2014 10:21 AM in response to Bill3Smith

So basically the symptoms are: Right after turning on the power strip that has the Mini's power supply on it, the Mini automatically starts (w/o having to hit the power switch) AND it has the date and time erased, everytime. And this happens whether there was a CMOS battery in or not...

It seems like if I want to turn off the power strip, to prevent the power supply drawing electricity during times the computer is off, I am doomed to be stuck in a perpetual PRAM zap loop? It didn't used to do this before the logic board's SMC button was likely pressed on accident way too many times.

The CMOS I have in there measured at 3V using my multimeter, but I am going to buy another new one with a "guaranteed good by" date, such as a Duracell, if possible.

The power button wires have already been cut & spliced to extend the power button out to the front of the G3. So I thought well maybe I didn't get the positive and negative wires back together correctly. So I tried reversing the polarity (cutting and splicing each wire over to the opposite wire) but it hasn't helped

Previous to this I have owned only desktops, and they are easy to get in there and fix if something goes wrong. That is the reason for this hack--to make my Mac Mini easier to access and work on. In the future obviously I will only buy Mac Pro towers. XD ha ha

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Answer 2

BDAqua

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Mar 22, 2014 11:13 AM in response to Bill3Smith

Hi Bill, you may be aware of this, but without AC power, the PRAM Battery will drain in pretty short order.

In System Preferences>Energy Saver>Options tab, is it set to Restart Automatically after a power failure?

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Answer 3

Bill3Smith Author

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Mar 22, 2014 5:04 PM in response to BDAqua

Thanks for the reply, BDAqua. I don't think I have Restart Automatically selected, but I will check. I'll post if that fixes it, but I think I probably don't have that selected.

Earlier today I put in a new CMOS battery measuring 3.3V, which couldn't possibly be too low to keep the date and time settings in the computer after the power strip is turned off. So then with the new CMOS in, I shut down the Mac, then turned off the power strip. After turning the power strip back on, it started itself up again, and as before, the correct date and time are gone.

Since at least a few threads on here say you shouldn't hit the logic board's SMC button more than once successively (it can damage the SMC chip), I am worried SMC damage is what is causing the CMOS's inability to hold the date and time when the power strip is turned off.

If that is the case, I am wondering if a re-flash of the SMC firmware could fix the damage I caused by inadvertently hitting this button so many times.

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Answer 4

BDAqua

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Mar 22, 2014 5:11 PM in response to Bill3Smith

I worry about that also, but haven't heard anything about SMC firmware resore working or not, or if it's even possible to do. 🙂

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Answer 5

Bill3Smith Author

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Mar 22, 2014 5:40 PM in response to BDAqua

Yeah, I know there's some EFI & SMC firmware updates released, but none for my specific Mac Mini (MacMini2,1)

So the only way to reflash the SMC firmware would be if I could get a copy of the original SMC firmware installer, which I haven't seen around anywhere.

There are CD images for download on Apple's website that you can use to restore firmware, but AFAIK they are only for if a firmware update failed to complete or else got interrupted by a power loss. And they don't let you go back to an earlier version of firmware than what is already installed. Anyway, thanks for trying to help, BDAqua.

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