View Full Version : 286 Data Bank CMOS

March 11th, 2017, 11:20 AM
Here is a nice board from a Compuadd 286 Data Bank unit. However, proper CMOS battery configuration is not yet confirmed. It seems that this system may require two batteries, one for the CMOS settings (lithim), and another for the clock (NiMH). Neither were present upon receipt, only a leaking alkaline battery pack. I once had a Packard Bell 386 that needed two batteries, but have not seem this on any other board.


March 11th, 2017, 11:42 PM
Hmm, in this photo I see only one battery location suited for different kinds of lithium batteries (axial type or coin type like the CR2032 in either upright or lying down version )
Normally the RTC and CMOS RAM are inside the same chip so can do with a single battery.

March 12th, 2017, 02:01 PM
Yes, however the J22 connector (near the keyboard connector) seems to support a TL5242 3.6V type of lithium battery. I tested and it only retained CMOS data, but no RTC. My guess is the original owner pulled the NiMH and ran 6V through the J22 connector exclusively. I suppose I am more curious as to the reasoning behind using two separate batteries (like with the Packard Bell PB300).