Active Topics

 


Reply
Thread Tools
joerg_rw's Avatar
Posts: 2,222 | Thanked: 12,651 times | Joined on Mar 2010 @ SOL 3
#1
some of you might never have known: N900 is not supposed to lose cmos-clock time and date ([edit] and alarms) on every battery swap. It's a tiny rechargable coin LiIon cell backup-battery (next to vibrator and power button) that's supposed to keep RTC aka cmos-clock running during months of main battery removed. Alas all those components break during a 12..24 months of usage, some even leak.
Now for the "bright" side of this story: the battery is easily replaceable when you got some moderate soldering skills (and tools), and using a
YUDEN, PAS414HR-VA5R, capacitor, 0.06F, 3.3V, STAKED COIN Coin Type Polyacene Capacitor https://hbe-shop.de/Art-2112777-TAIY...3V-STAKED-COIN will avoid having it broken again in another 12 months of time. (datasheet)

[edit]my local stock of those ran out, so the following doesn't apply anymore[/edit]
For your convenience I got some of those components as of above, and I'm willing to ship them worldwide via simple letter, for a 3EUR donation per unit to maemo donation paypal account. Contact me via IRC(freenode.net):#maemo or by mail to techstaff at maemo.org, or simply donate and give FULL addr plus your online contact (mail or IRC) in "message to account owner"

some macro-shots (taken with N900):
pointing to coin cell with a red balltip fine pen left black switch is camera trigger, right one (white head) is power button. The huge silver thing below the coin is vibrator also see http://maemo.cloud-7.de/Gallery-N900-exploded/

cheers
jOERG
__________________
Maemo Community Council member [2012-10, 2013-05, 2013-11, 2014-06 terms]
Hildon Foundation Council inaugural member.
MCe.V. foundation member

EX Hildon Foundation approved
Maemo Administration Coordinator (stepped down due to bullying 2014-04-05)
aka "techstaff" - the guys who keep your infra running - Devotion to Duty http://xkcd.com/705/

IRC(freenode): DocScrutinizer*
First USB hostmode fanatic, father of H-E-N

Last edited by joerg_rw; 2014-05-09 at 12:59.
 

The Following 37 Users Say Thank You to joerg_rw For This Useful Post:
peterleinchen's Avatar
Posts: 4,118 | Thanked: 8,901 times | Joined on Aug 2010 @ Ruhrgebiet, Germany
#2
Thanx for finding and bringing to us/community.

--
unfortunately my soldering skills are weak weaker ...
last time it was cmos batt on 486 and I dropped a bit of tin into RAM blocks , but hey it still ran
otherwise I would immediately go for one from you
__________________
SIM-Switcher, automated SIM switching with a Double (Dual) SIM adapter
--
Thank you all for voting me into the Community Council 2014-2016!

Please consider your membership / supporting Maemo e.V. and help to spread this by following/copying this link to your TMO signature:
[MC eV] Maemo Community eV membership application, http://talk.maemo.org/showthread.php?t=94257

editsignature, http://talk.maemo.org/profile.php?do=editsignature
 

The Following 2 Users Say Thank You to peterleinchen For This Useful Post:
Alecsandru's Avatar
Posts: 439 | Thanked: 282 times | Joined on Oct 2012
#3
could swap that with a capacitor?
__________________
N900 Beast featuring :
8GB OPTFS@ext4(*performance mount options)
overclock: cpu[125 - 1,150(*VDD1)+Dsp overclock
CSSU-T latest version
 

The Following User Says Thank You to Alecsandru For This Useful Post:
Posts: 23 | Thanked: 23 times | Joined on Jul 2012
#4
Originally Posted by Alecsandru View Post
could swap that with a capacitor?
Kondensator _means_ capacitor, that's the whole point, I'd say :-)
 

The Following 3 Users Say Thank You to LinuxCub For This Useful Post:
Alecsandru's Avatar
Posts: 439 | Thanked: 282 times | Joined on Oct 2012
#5
i mean a smd one , not battery , just one smd capacitor or
maybe an electrolitic one
__________________
N900 Beast featuring :
8GB OPTFS@ext4(*performance mount options)
overclock: cpu[125 - 1,150(*VDD1)+Dsp overclock
CSSU-T latest version

Last edited by Alecsandru; 2013-07-27 at 12:32.
 

The Following User Says Thank You to Alecsandru For This Useful Post:
joerg_rw's Avatar
Posts: 2,222 | Thanked: 12,651 times | Joined on Mar 2010 @ SOL 3
#6
Originally Posted by Alecsandru View Post
i mean a smd one , not battery , just one smd capacitor or
In theory yes. Though F=As/V, do the math. A 100uF might suffice for some seconds of RTC operation, and a 100uF is already not exactly a small formfactor. 3.6V voltage minimum needed anyway.
/j
__________________
Maemo Community Council member [2012-10, 2013-05, 2013-11, 2014-06 terms]
Hildon Foundation Council inaugural member.
MCe.V. foundation member

EX Hildon Foundation approved
Maemo Administration Coordinator (stepped down due to bullying 2014-04-05)
aka "techstaff" - the guys who keep your infra running - Devotion to Duty http://xkcd.com/705/

IRC(freenode): DocScrutinizer*
First USB hostmode fanatic, father of H-E-N
 

The Following User Says Thank You to joerg_rw For This Useful Post:
Posts: 44 | Thanked: 38 times | Joined on Mar 2010 @ Germany
#7
Funny, I got so used to setting date/time after swapping batteries that I assumed this had always be the case.

However, since the n900 is still my main phone (I'd like to keep it like this for the next couple of years to come) and I don't trust my soldering skills, I'm not going to attempt a hardware fix. But thanks for sharing this information with the community.
 

The Following 3 Users Say Thank You to BigLebowski For This Useful Post:
Guest | Posts: n/a | Thanked: 0 times | Joined on
#8
good post.
For those considering doing the soldering themself, you should be aware of RoHS. (http://en.m.wikipedia.org/wiki/Restr...nces_Directive)
Shortly, you need higher temperature when soldering this, than with usual lead.
going to ask a good friend myself
 

The Following User Says Thank You to For This Useful Post:
nokiabot's Avatar
Posts: 1,974 | Thanked: 1,834 times | Joined on Mar 2013 @ india
#9
reserve one for me as i cant find one . Long story ...
 

The Following User Says Thank You to nokiabot For This Useful Post:
pichlo's Avatar
Posts: 6,447 | Thanked: 20,981 times | Joined on Sep 2012 @ UK
#10
is there a limit per person? I'd like three...
 

The Following 2 Users Say Thank You to pichlo For This Useful Post:
Reply

Tags
battery, clock cmos rtc, hardware hackin, nokia n900, soldering


 
Forum Jump


All times are GMT. The time now is 18:15.