[Gta04-owner] problems with battery loading

t.munker at gmx.net t.munker at gmx.net
Sat Jun 4 22:16:17 CEST 2016


Hi,
no, i didn't have the time to do something, yet. But since my data
connection also got worse, i really think its the soldering. So i want
to try resoldering, soon.

What you describe sounds very similar...

Kind regards,
Thomas 


Am Sat, 4 Jun 2016 16:47:00 +0200
schrieb "H. Nikolaus Schaller" <hns at goldelico.com>:

> Hi,
> did you have success yet?
> 
> We are currently running our OpenPhoenux hacking weekend and I have
> just observed a strange thing with the USB charger:
> 
> if I unplug and replug the USB cable on the PC side the GTA04 (with
> 4.7-rc1 kernel) does not recognise that event. But if I unplug the
> USB cable at the GTA04 end it is recognised.
> 
> This looks a little similar to your issue report.
> 
> BR,
> Nikolaus
> 
> 
> 
> > Am 27.05.2016 um 21:20 schrieb t.munker at gmx.net:
> > 
> > Hi,
> > my guess was that i did some short circuit (maybe with some higher
> > resistance) so that voltage is brought from VBUS to the charging
> > detection pin. But since VBUS is used to charge, i don't know. maybe
> > the cables impedance plays a role and acts as a small capacitor in
> > combination to some resistances i introduced while soldering the new
> > connector?
> > 
> > I've measured at the big usb-end of my charging cable and got
> > following readings:
> > left: 0 Volt  to shielding
> > middle two pins: did't care much, something between 0.6 and 0.9 Volt
> > right: 5,xx Volt
> > 
> > I can't see any suspicious in these measurements.
> > 
> > I am waiting to buy/lent me an hot air gun, before i open up the
> > phone and maybe try to resolder again.
> > 
> > Is there any way to ensure that not the IC mentioned by Nikolaus
> > is defect? 
> > Any other thoughts?
> > 
> > kind regards,
> > Thomas Munker
> > 
> > 
> > 
> > Am Fri, 27 May 2016 12:13:54 +0200
> > schrieb "H. Nikolaus Schaller" <hns at goldelico.com>:
> >   
> >> Hi,
> >>   
> >>> Am 26.05.2016 um 23:33 schrieb <t.munker at gmx.net>
> >>> <t.munker at gmx.net>:
> >>> 
> >>> Hi,
> >>> thanks for your answer so far!
> >>> I still have some questions:
> >>> 
> >>> Am Thu, 26 May 2016 23:07:29 +0200
> >>> schrieb "H. Nikolaus Schaller" <hns at goldelico.com>:
> >>>   
> >>>> Hi,
> >>>>   
> >>>>> Am 26.05.2016 um 20:14 schrieb <t.munker at gmx.net>
> >>>>> <t.munker at gmx.net>:
> >>>>> 
> >>>>> Hi,
> >>>>> i've got some problem with loading my battery.
> >>>>> 
> >>>>> Symptoms are:
> >>>>> When plugging usb line in at the phone, phone wakes up and
> >>>>> starts loading, if there is power.    
> >>>> 
> >>>> Even without the cable connected on the other end?  
> >>> 
> >>> The phone even wakes up without the other cable end connected. But
> >>> does not start loading, since there is no power...  
> >> 
> >> That is really strange. Wake-up means that there is some power
> >> detected on the VBUS line. But how connecting just a cable with
> >> open other end can do this is strange.
> >>   
> >>>   
> >>>>   
> >>>>> Plugging in at the other end of the usb line is not detected
> >>>>> (when first plugged in at phone, phone wakes up, but can't load
> >>>>> since there is no power and goes sleeping again)
> >>>>> After some seconds (mostly) (sometimes even about half an hour)
> >>>>> it stops loading, even when battery capacity is still
> >>>>> critical.    
> >>>> 
> >>>> Hm. Looks like broken cable.  
> >>> 
> >>> Since i used different cables, i would suspect the connector.
> >>>   
> >>>>   
> >>>>> 
> >>>>> Old openmoko power adapter doesn't seem to work at all.
> >>>>> 
> >>>>> To get the phone usable i need to watch it closely, and unplug
> >>>>> and replug it, if it stops loading.
> >>>>> 
> >>>>> 
> >>>>> Environment:
> >>>>> I use QTMoko. Since this has some lag until plugging is
> >>>>> detected, i use neocontrol to view power status.
> >>>>> I resoldered my usb-port, maybe something went wrong there. But
> >>>>> right after resoldering it, it was working good and now got
> >>>>> slowly worse... Also the sd-card got already corrupted at some
> >>>>> point, i will reinstall next days to exclude a software error
> >>>>> 
> >>>>> 
> >>>>> Where i need help:
> >>>>> Is there some way to determine why the phone stops loading?    
> >>>> 
> >>>> I don't know about tools but latest QtMoko still uses the old 3.7
> >>>> kernel which does not have a good charger driver. The main
> >>>> problem is that it simply stops charging as soon as the USB
> >>>> voltage inside the GTA04 drops below 4.5V. And does not restart
> >>>> unless you unplug
> >>>> + replug the cable.
> >>>> 
> >>>> This may have a reason in a weak cable or weak power supply,
> >>>> especially with almost empty battery when the charging current
> >>>> going through the cable (in parallel to operating the GTA04) is
> >>>> highest. This may be ~800 mA...
> >>>>   
> >>>>> 
> >>>>> When i want to check my usb-port, is this possible with a simple
> >>>>> ohm-/volt-/ampere-meter? What are the readings that i should
> >>>>> expect between the usb-pins when connected correctly to the
> >>>>> board?    
> >>>> 
> >>>> A common source of trouble is if the GND or the shield is not
> >>>> really connected. This may happen during repair. So you should
> >>>> check if you have 0V on GND
> >>>> 3.3V on data lines (may be there only for a very short test cycle
> >>>> so you can't notice) ca. 1V on the ID line
> >>>> 5V on the VBUS line
> >>>> 
> >>>> For charging, the data lines are not used. Therefore having a
> >>>> good 5V input is most important.  
> >>> 
> >>> i don't have a clue about the usb-standard, so i describe here
> >>> what i hopefully understood:
> >>> When i look at the big connector side of my usb
> >>> cable (other side connected to the phone), i guess the left of the
> >>> outer pins should be GND and have 0V (and 0Ohm) to the
> >>> shielding.  
> >> 
> >> Yes. Or no. Some cables have 0 Ohm to shielding others don't. But
> >> the GTA04 should have 0 Ohm between both.
> >>   
> >>> The two inner pins are the data lines, of which one should have
> >>> 3.3V for some micro seconds and the other is the ID Line and
> >>> should have 1V (both against the GND, and shield).  
> >> 
> >> Yes.
> >>   
> >>> The right outer pin then is the VBUS line and should measure 5V to
> >>> GND.  
> >> 
> >> Yes.
> >>   
> >>> 
> >>> Is there something to say about the resistances between the lines
> >>> on the phone? I want to check if i did some bad connections...  
> >> 
> >> If you take an ohmmeter (with low voltage!) you can usually see
> >> some values above kOhms.
> >>   
> >>> 
> >>> I guess i have to measure voltages, while the gta04 is running?  
> >> 
> >> Yes.
> >>   
> >>> If this
> >>> should be measured while gta04 is off and connected to some power
> >>> source, how can i measure them (where should i point my measure
> >>> tip)?   
> >> 
> >> Hm. It could also be a broken ESD chip. It has some diodes inside
> >> which protect against overvoltage but are high resistance if
> >> voltages are ok.
> >> 
> >> If these diodes allow reverse-current, a voltage on some data line
> >> may rise VBUS to a level that is detected as a charger wakeup
> >> event.
> >> 
> >> On the other hand it still does not explain why it happens with a
> >> cable not plugged to a power supply...
> >> 
> >> BR,
> >> Nikolaus
> >> 
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> > 
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