Trying to help a friend who has a IBM PC-350 computer that doesn't keep cmos setting. Coin battery is not the problem. I took the motherboard out of the case ,it is an OEM Intel Advanced/MN Morrison, using 430FX chipset (socket 5).

IBM at factory installed blue jump wire between ALS245a (this has 5v on it's chip enable pin) connected to a vias that connects to the 'Chip enable' pin on the E28f002 intel bios chip. To check I have desoldered this wire and as expected motherboard will not boot without it.

Also a factory installed yellow jump wire connected between CR7A2 and CK7A1 close the the cr2032 socket. I'm not sure what this does other than take 3.3v from the cr2032 to somewhere.

Looking at retail intel advanced/MN boards they do not contain these modifications (only other difference is they have onboard crystal audio chip and onboard S3 trio32, this board has trio64).

The main problem is the CMOS doesn't save any settings or time/date. Tried new batteries but the board acts like no battery is installed and doesn't save settings or time/date. I first though the yellow jump wire close to the cr2032 is the cause even though it is a factory install wire. I cut the wire but same problem, no cmos setting are saved after reset.

The CMOS and Clock is in the NS PC87306 Super I/O chip . According to it's datasheet pin 7 is Vbat for the Clock and CMOS. Measuring this I get 0.2v. Can't go further as pin 7 trace appears to go nowhere from the PC87306 chip.