Building a replacement 386/486 CMOS battery
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Building a replacement 386/486 CMOS battery
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Re: Building a replacement 386/486 CMOS battery
#2The only thing worse than these soldered-in batteries are those motherboards with the Dallas DS1287 RTC “brick” ICs. They had a coin cell buried inside the chip[1] with no way to provide external power should it drain.
Re: Building a replacement 386/486 CMOS battery
#3Why not use lithium AA? Duracell aklaleaks are the worse, in my experience. At least if the alkalines do leak, they're in a carrier away from the MB.
Re: Building a replacement 386/486 CMOS battery
#4The only thing worse than these soldered-in batteries are those motherboards with the Dallas DS1287 RTC “brick” ICs. They had a coin cell buried inside the chip[1] with no way to provide external power should it drain. [1]: http://www.mcamafia.de/mcapage0/dsrework.htm
The only thing worse than that is when those things are soldered and not in a DIP socket. They still make them (or a compatible version) by the way, sealed battery and all.
Re: Building a replacement 386/486 CMOS battery
#5Why not use lithium AA? Duracell aklaleaks are the worse, in my experience. At least if the alkalines do leak, they're in a carrier away from the MB.
They’re using rechargeable NiMh, not alkalines. I would have used the older Eneloops or current Fujitsus, but maybe rechargeable Duracells have better quality than their alkalines.
Re: Building a replacement 386/486 CMOS battery
#6Lots of older Apple hardware used soldered-in 1/2AA lithium batteries. You can replace them with a removable battery holder that was used on some later board versions.
https://www.mouser.com/ProductDetail/Keystone-Electronics/10...
https://www.mouser.com/ProductDetail/Keystone-Electronics/10...
Re: Building a replacement 386/486 CMOS battery
#7I took this same approach when I repaired a 386 damaged by a Varta battery. After fixing some motherboard traces, I installed a Velcro’s 3xAAA battery holder in my case for the same effect.
https://justinmiller.io/posts/2020/06/17/project-386-part-4/
Re: Building a replacement 386/486 CMOS battery
#8The only thing worse than these soldered-in batteries are those motherboards with the Dallas DS1287 RTC “brick” ICs. They had a coin cell buried inside the chip[1] with no way to provide external power should it drain. [1]: http://www.mcamafia.de/mcapage0/dsrework.htm
Ah yes. I've had to repair one of the Dallas ICs before. You have to dig out a dremel and bite down till you get to the metal then add some hook up wire. Unlike OP I chose to use rechargable batteries that used to be used for home wireless phones - they are the right voltage and often they supply a battery charger.
If you're lucky you can desolder the the old battery and use a couple of pin headers to get you back up and running. I do find it irritating some retro machines wont even boot without a working battery.
Re: Building a replacement 386/486 CMOS battery
#9Why not use lithium AA? Duracell aklaleaks are the worse, in my experience. At least if the alkalines do leak, they're in a carrier away from the MB.
They’re using rechargeable NiMh, not alkalines. I would have used the older Eneloops or current Fujitsus, but maybe rechargeable Duracells have better quality than their alkalines.
The NiMH Duracells are very high quality (at least according to Project Farm).
Re: Building a replacement 386/486 CMOS battery
#10I actually did the same thing for my old 286 ages ago, worked great for many years. Sadly I moved to a smaller place and was stupid enough to toss it out :(
Too bad they went to soldered batteries, decades ago people realy knew how to design systems in the old days. Now, not so much.