MobilePro 790 Power Issue

Well, physically they seem fine, but that does jive with the state of the outside of the case...

Edit: p.s. the notification light (which is, say, 4mm to the right of them) is fine.

Edited by thenzero 2023-01-18 10:12 PM

How long should one normally be able to leave the battery out without having to reset? I'm guessing multiple hours?

I would work more on minutes than hours, but not seconds.

Ok thank you C:Amie

Love these flakey old things when they don't work. Drives you nuts. But to answer one question, yes...the backup battery can read good through the CE control panel and really be bad. It uses voltage potential only to make that determination...not current draw or capacity under load like newer devices. Under ideal conditions, when my 770 was brand new, I could maintain memory integrity for 40-50 minutes with the unit off, no ac power, and the main battery unplugged. Also good to remember is the rechargeable battery is charged from the main battery, not the ac adapter. Hence why you are warned in the "important notes" that comes with a new machine to let the unit charge for a full 10 hours before using it...despite the fact that new units normally came with the main cell at 70% full charge. They wanted to insure the backup battery was charged to maximum capacity as well. And they also warn you..plug the unit in when changing the main battery. Don't rely on the backup battery to keep memory intact. As far as the frozen "Mobilepro logo" boot screen...I've experienced that as well. Sometimes, if I leave it alone...5 or more minutes...booting will spontaneously occur. Other times nothing even after 30 minutes...requiring me to complete a hard reset.

I know that the 95LX got problem with the backup battery because of a defect Tantal inside. That was the reason that the device thought the battery was empty.

Great info, thanks Rich. Do you know if the backup battery/system come into play for anything other than maintaining RAM during a batt swap?

Interesting. Any thoughts on the cap discussion up thread? Specifically is it sufficient to measure/verify the capacitance of the three charge pump (or whatever they are) caps next to the battery?

It'll keep the RTC going and the memory controller, otherwise DRAM wouldn't know when to strobe.