non-booting C700 Options

[rabidhamster]

Hi. I got a 2nd-hand C700, and it won't start up. I can get into the DM and DB menus fine, but the power button does nothing.

I have backed up and then restored the NAND flash with a file I found on the internet as well - no change

The battery doesn't appear to charge too well, which is odd. Would this stop the zaurus from booting properly, even though it has power on it?

Is there anything i'm missing here, or anything you guys suggest that might help fix it? I've run the tests in the menu and apart from the non-booting the zaurus seems to work perfectly

cheers,
- Gordon

[piotr]

fistly charge battery outside zaurus to be completly sure it is fully charged. My zausus also wont start if battery isnt charged.
Secondly - You ve wrote that you reflash nand. So you have working that part of rom. Good.
Try powerbutton on the back side of the unit - my Z sometime work only with it. press it for 10-15 sec.
There are my first thoughts. Write here if they didnt worked.
piotr

[rabidhamster]

Thanks for the help. What did you mean by the power button on the back? Is there something other than the silver one next to 'Ok'/'Cancel'.

I have a zaurus 5500 coming soon - is the battery in this the same as the c700? If not i'll try and rig something up to charge the battery outside...

I bought a compactflash card and followed the instructions to completely re-flash (with DC keys). This didn't make the 'Ok' screen appear though.

Some info that might be of use:
DS works
DM works
'Ok' doesn't

Kernel 2.78 reported on DS

on DM:
NAND Diag ver. 1.00
V:0031
Cortulla c700
ROM checksum 4ee1
MAINTE 1.00
DIAG 1.00
KERNEL2 1.00
FLSYS2 1.00
KERNEL1 1.50
ROFLSYS 1.50
PRESET 1.0
INFO 1.0
MASTER 1.50

The charging light blinks once, then comes on full after about 2 secs. BUT... after about 1/2 hour it starts flashing, and the battery isn't charged. At the moment the battery has 0 volts, however at some points its had 3.2.

- Gordon

[rabidhamster]

Hi. I just put a burst of power into the battery that brought it up to 3.6v - this was actually enough to get the 'Ok' menu, and i could reset, and its all working perfectly now.

thanks!
(its still not charging the battery very fast though - i may totally charge it outside the PDA but don't have the means here )

[cterry]

How did you charge the battery outside the zaurus? :?:

[piotr]

Second ON/OFF button is on the same side with SD card.
Charging circuit in Cxx0 is very weak and fragile. Propably Your zaurus don't charge the battery.
Battery from 5500 is the same like in c700. You can charge it in 5500.
Piotr

[bastichelaar]

How did you charge the battery outside the zaurus? I'm curious too...

[rabidhamster]

I used a resistor to connect 5v from a plug in the wall power supply to the battery's terminals. It puts some power in but you can only sensibly use the resistor for short periods of time as there is no charge circuitry

I have been using a zaurus 5500 i got since though. I have looked inside the C700 and have found 2 chips that could have got broken from a bad charger. I'll try and replace them and see if this makes it work.

Has anyone else had any experience in repairing a zaurus? (apart from sending it back...)

[waalkman]

Hi. I just put a burst of power into the battery that brought it up to 3.6v - this was actually enough to get the 'Ok' menu, and i could reset, and its all working perfectly now.

Good Grief.

(its still not charging the battery very fast though - i may totally charge it outside the PDA but don't have the means here )

Here's a simple li-ion charger using the bq2057 chip. See page 7:
http://focus.ti.com/lit/ds/symlink/bq2057.pdf


The 2057 will charge either a 4.1 or 4.2 volt battery (yes, there is a difference). It probably determines which type of battery you have by reading the battery's thermisitor. I can't say for sure. But it's apparent that you must use the battery's thermisitor lead for this to work correctly.

The Rsns resistor (in the example this is a .2 ohm resistor) can be adjusted for the charging current that you want. .2 for 1A (and I presume) .1 for 2A.

And of course you still have to supply it with clean power. But that could even be a battery pack if you like.

Digikey sells the 2057 for $3.04 each.
http://www.digikey.com/scripts/dksearch/dk...2057DGK&site=us

The rest of the parts look cheap. Please be careful.


The way that I would approach the "repair" of your Z would be to bring all three leads out of the Z to your homebrew charger. This way you can leave the battery in while charging it and you won't have to crack the case to get into the internals. This does mean that you would have to build a 3 conductor cable, but so what?

And I would be really careful the first few times that I used the charger - like in the other room when you start it up. Be sure to read the app notes carefully, check your math (but it really does look pretty simple - and foolproof).


John

[rabidhamster]

Sounds good. I was planning on changing the current charger ICs that are in the zaurus though - i've found out which ones, and I think the broken part is probably just an FET. have you had any experience with repairs on the Z?

Totally changing the charge circuit may well prove to be the best idea though. I was however worried about getting it to work nicely with the rest of the Z - for example the charge light couldn't easily be connected using that chip (others available use a pull-down output though so if i looked around i might find a reasonable replacement).

- Gordon

[seva]

Sounds good. I was planning on changing the current charger ICs that are in the zaurus though - i've found out which ones, and I think the broken part is probably just an FET. have you had any experience with repairs on the Z?

Totally changing the charge circuit may well prove to be the best idea though. I was however worried about getting it to work nicely with the rest of the Z - for example the charge light couldn't easily be connected using that chip (others available use a pull-down output though so if i looked around i might find a reasonable replacement).

- Gordon

Do you have any updates on this?

Take a look at C-860 charging problem (not battery)