OESF Portables Forum

Everything Else => Sharp Zaurus => Model Specific Forums => Distros, Development, and Model Specific Forums => Archived Forums => C1000/3x00 Hardware => Topic started by: gdog on June 11, 2005, 06:02:41 pm

Title: Zaurus Charges But Won't Run On Full Battery
Post by: gdog on June 11, 2005, 06:02:41 pm
I've gone back and forth on these forums looking for an answer, finding things as unlikely as putting the battery in the freezer (however effective it might be in some cases).

My C1K will work fine as long as it's plugged into the wall. Charging light comes on, and eventually goes off, but as soon as I disconnect it I get the black screen of death. Both the original battery and the battery that I ironically just received the day after my Z bricked have enough power in them to help me into the service menus, but won't power the device, even when fully charged.

I can't seem to find anything anywhere that gives detailed instructions on how fix this. One of the grey market vendors was kind enough to try to help, but essentially has thrown up his hands and asked me to let him know what Japan says the problem is. My problem is I can't send it to Japan because I bought it used and so even though it is only a couple of months old I'm stuck basically with a system that must be used while connected to a wall socket.

My EA-72 is putting out 5.14vdc according to my Beckman Multi-meter (very accurate professional meter).

Now here's the strange thing. The brand new battery I bought and received yesterday measured out at 3.4v out of the box. I just took it out of the system after charging it and then trying to boot the system on it unsuccessfully. Immediately after it failed I measured it on the same Beckman meter and it measures out at 4.17v. So it is charging, but the system at this point just won't seem run on the ~4.2vdc that the battery puts out, or just won't run on the battery itself. So is it a charging problem or actually something else?

Sure was nice while it lasted,

gdog
Title: Zaurus Charges But Won't Run On Full Battery
Post by: omega on June 13, 2005, 04:56:00 am
~4.2 is 100% for these Lithium-ion batterys, and they should run down to about ~3.6volts  I was going to suggest the battery is fried, but since you have a second new one and they let you into the service menu that's not the problem.

Also since it will power on from the battery (to let you into the service menu), then the battery is powering the device...  It seems to suggest a software problem... or a hardware problem, regarding the battery level sensing circuitry may be damaged, so that it thinks the battery is always dead...

Did you try a ROM restore?
Title: Zaurus Charges But Won't Run On Full Battery
Post by: gdog on June 14, 2005, 11:05:49 am
Quote
~4.2 is 100% for these Lithium-ion batterys, and they should run down to about ~3.6volts  I was going to suggest the battery is fried, but since you have a second new one and they let you into the service menu that's not the problem.

Also since it will power on from the battery (to let you into the service menu), then the battery is powering the device...  It seems to suggest a software problem... or a hardware problem, regarding the battery level sensing circuitry may be damaged, so that it thinks the battery is always dead...

Did you try a ROM restore?
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omega,
You're right on with your first two descriptions, and I have the same guess you do on the sensing circuitry. The one thing I haven't tried is a restore. Probably don't have much to lose, but I have promised the unit to a fellow member, and he can try it. If it works for him he gets a very nice, 2 month-old unit for a very good price. As for me I've ordered a new one so that I'll have the adapter that does not seem to be suspect (EA-70s), and a warranty.

Thanks for the suggestion. Very helpful people all over the place on this board.

Regards,

gdog
Title: Zaurus Charges But Won't Run On Full Battery
Post by: omega on June 14, 2005, 11:56:46 am
Good man. 8-)

Indeed, there is a very helpful bunch of people here! Glad to hear you ordered another one, stick with the Zaurus. Oh and if you have trouble with the new one, I might swap you my perfect C860 for it! ;-)
Title: Zaurus Charges But Won't Run On Full Battery
Post by: omega on June 16, 2005, 04:00:57 am
So you got it fixed with a software restore? Cool.
Title: Zaurus Charges But Won't Run On Full Battery
Post by: gdog on June 17, 2005, 01:42:36 am
Quote
So you got it fixed with a software restore? Cool.
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omega,

I did, and maslovsky was very gracious in ageeing to call off the deal once the unit had been restored to full functionality. It was really a fluke kind of thing because I was actually preparing to do a hard reset to ready it for shipment when I thought of what you had written and said to myself what the heck it's worth a try. And it worked like a charm. I already thanked him, as you apparently know, and now I'd like to thank you.
And Kahm as he had actually suggested something similar right off the bat, but I have been very busy at work and didn't have time to look into it much at the time.  Like I said there's lots of help and good folks on this board.

One thing that seemed to differ in the symptoms that my Z showed from what most report is that my charging circuit apparently never stopped working. I know this because I tested both the adapter and the battery after charging it and watching the light go off on the unit. The battery read 4.24v and the output of the adapter 5.14v. The only thing my unit would not do was either run without the adpater plugged into it, or have the backlight function for more than a second. I'm not sure which, but as I say the symptoms are somewhat different than what most folks are seeing.

Regards,

gdog