In the Mac Pro from the same era, the BR2032 is the one we use. The CR2032 can not handle the temperature and will last only for some months.
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Hmmm. Looking at the service manual again, I realise that “CR2032” actually only appears in a photo (page 54). It’s only really specified as Apple part number 922-6476 (page 250).
iFixit’s guide for the year-later 20" 2009 iMac does state the BR2032. But, unless I’ve got muddled up, the service manual for that model - iMac (20-inch, Early/Mid 2009) shows a photo of a CR2032 again, this time specifying Apple part 922-8892.
So there is a discrepancy. Perhaps iFixit have the wrong details?
But TheBookYard agree with iFixit - they also list the BR2032 for iMac 20" Early/Mid 2009. I don’t know where their information comes from. It’s possible they are relying on the iFixit information, but I get the impression their data is based on their own repairs.
My guess is that the photos in Apple’s service manuals are wrong. In that context, the part number would certainly be expected to take precedence. Sorry if I’ve misled here.
Agreed. Adapters like this are a great addition to a toolkit. I keep one of these on-hand:
This device has three different connectors for attaching drives:
- SATA
- PATA (for 3.5" drives)
- PATA (for 2.5" drives)
It connects to your computer with a USB 3.0 type-A cable and can support drives larger than 2TB.
Before I got that adapter, I used to use a Bytecc BT-300, which a similar adapter. But it is USB 2.0 only and only supports drives up to 2TB. (I replaced it with the Fideco device when I needed to access larger drives).
Interesting. Ultimately, I don’t think it matters too much - they’re the same size and have the same nominal voltage. I do believe, however, that a BR2032 will last longer for this kind of application (maintaining PRAM and the clock when the computer is disconnected from mains power).
This is interesting information. So you think the fact my friend unplugged his iMac (and his former partner’s iMac) let to the little battery not maintaining the PRAM when it died out and that’s the reason it won’t start?
In that case, just plugging it in won’t reboot (or whatever you call it) the PRAM?
Wow. Look at the steps you need to follow to replace the battery! Why did they make it so difficult if it is such an important part and one that naturally wears out over time?
I don’t know, but it may be a possibility. I know of many old electronic devices that have a hard time booting if they have a dead battery - usually due to battery-backed RAM having random values. In the past, I remember PowerPC Macs would sometimes not boot if the PRAM lost its values, but those systems have a button on the motherboard to reset the PMU (power management unit), which would usually let it boot up properly, especially after changing the battery.
But as others have reported, there could be many other possibilities, including a bad power supply or leaking capacitors. Fixing these is more difficult than just replacing a battery.
The main reason I’ve been taking about the PRAM battery is simply because once you’ve got the front bezel off, it’s a quick and easy thing to replace. So once you’ve decided to actually open the case, you might as well change it, just in case it’s enough.
The CRT fruit colored iMacs used to exhibit the behavior where they wouldn’t always power on with a weak battery. This usually happened after being unplugged or after a power failure. Replacing the battery was not always enough. You also had to take out the RAM chips, reinsert and press the reset button and they came back up.
My old Performa 6400 never has done this. I know when the battery goes out since it will say that the date is incorrect but it always boots up unlike some of those iMacs.
Reminds me of that wonderful breakthrough with IBM PCs when they remembered the date on boot up!
Back on topic, I had an iMac of that vintage that failed to boot and I was told by the service people that the motherboard had failed. It was time for a new Mac.
In this case both my friend’s iMac and his late partner’s iMac both failed. Coincidentally 6 months after (for some reason) he decided to unplug both.
So weird about that battery being needed to just start up.
I seriously doubt that a dead internal battery would stop an old iMac from starting up. The most common symptom of a dead iMac battery is that the computer will no longer keep proper track of the current time. Your friend should ask an independent Mac repair shop to open the dead iMac and pull the hard disk, which may still be working. If so, the bare drive can be put into a cheap hard drive enclosure from Amazon in order to copy the data to another location. A generic enclosure will likely be much cheaper than the fancy connection kit pictured in one reader’s reply.
According to multiple sources, a dead internal battery can prevent some Mac models from starting:
https://discussions.apple.com/thread/3852913?sortBy=best
A 13+ year old battery from a system that hasn’t been plugged in for 6+ months would be a very likely suspect for failure.
I already stated earlier that this was an issue with multiple older CRT iMac’s so I know from my experience it has been a problem. Each model has its own variabilities but I experienced the problem enough times to have some knowledge of it and it was always older batteries and/or after a power failure.
The disappointing part of all this is that for a tiny part that naturally dies over time anyway that Apple didn’t just include a simple battery slot! Sort of unbelievable actually.
Very true. At least the old CRT iMacs had a drop down door at the bottom of the unit so you had fairly easy access although it could be tricky for some users. I’ve also replaced a few batteries in the earlier Mac Mini’s and those have more steps to get to the battery but still not too bad once the case comes off. But the computer you’re talking about seems more complicated because of the screen.
In the early 2000’s I was a computer tech at an elementary school. Every September I had to deal with several Macintoshes (as they were known then) that wouldn’t boot; the cause was always a dead battery because they had been unplugged for the summer.
Very interesting. I have owned many iMacs over the years, and a few of them eventually lost the ability to remember the correct time; but none of them ever stopped starting and running. Love and learn.
David, are you confident that they won’t leak? We have a original “desk lamp” iMac G4 that we would like to keep running. (I just fired it up to read some old CD’s we have that nothing else would read). It booted up fine, but didn’t know the time or where it was (I didn’t bring it online). I would hate to lose it to a broken battery (like my beloved Amiga 4000). I was going to go ahead and do it, but I can’t find the battery iFIXIT says it needs. Their Amazon link is no good…
Thanks.
I believe that the battery is a LS14250 3.6V Lithium battery. If so, Amazon has a boatload of them for sale.
Most of them are not rechargeable though. The ones iFIXIT linked to on Amazon were no longer available. The rechargeable version took me three sessions to finally find. Searching for “rechargeable” found all the “not rechargeable” ones too, which they all clearly stated. And as you say, there was a boatload to sort through. But thanks.
I wouldn’t worry about getting a rechargeable battery. A new, standard lithium battery from a reputable manufacturer can last for a decade as a PRAM battery, especially if the computer is maintained under normal environmental conditions. For a twenty-year-old machine, a leaking capacitor is a much greater risk than a new PRAM battery.
If you’re truly concerned, inspect the motherboard for swollen or leaking capacitors. If you’re not comfortable doing it yourself, ask for rates and drop it off at an electronics shop and have them inspect and replace capacitors. (Capacitors are inexpensive. The fee should be almost all labor.) For a vintage machine that is important to you, I’d go so far as putting a reminder in my calendar to look at it every couple of years.