Chinese Phones

Discussion in 'General Electronics Chat' started by R!f@@, Dec 29, 2010.

  1. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    You know those who collect trash. You have em, & we have em.
    One mans trash is another mans treasure after all.

    It so happens that we too have a gold miner, collecting all sorts of stuff.
    Phones, computer parts, TV's ...u name it..:p

    I tumbled upon a relative who is into electronics junk collection, I must say it is pretty rewarding since now I have seen the stuff he has.
    From time to time I help him to fix TV's tht he brings from trash. Still I wonder why people are throwing things that can be fixed. Cause I have fixed all and every TV he salvaged. All for free..so he can sell 'em & be happy..

    What this thread is all about is about a battery. you see he has lot's of & lot's of phones. Working ones with minute problems....beautiful phones...latest N98i too. ...

    I thought I too would repair a couple of phones and give to the kids in the family to play with. With that in mind I took a few phones. Talk about tht later....

    The phone with me right now is a typical dual sim Chinese phone...but quite nice one.
    It so happens that this phone was sold to some one by the collector and since it is not charging, the guy has been running around the capital trying to find a way fix the charging problem. But Alas all his effort ends up with a No.
    Being a Chinese one, and I guess one of it's kind, this phone has no other replacement. So how can he can get it fixed by the popular wannabees.
    No replacement battery, no charger. nothing..all is lost.
    I thought, why the heck did he buy it from a trash collector in the first place..it could be tht the collector has a few tricks up his sleeves.

    The collector charged a good battery and installed it in the phone. Some how he had put another battery , some what similar in to the phone and sold a nice working phone..:D.

    Nice deal....but one problem. No charger. Once the battery discharge's, there is no way to charge it but to take the bat out and use a stand alone charger. I guess Chinese guys are always on the go carrying a second battery in the pocket. Cause from the looks of it, this phone too seems to have a second battery in the holster.
    Two batteries. One in the phone and another embedded in the phone cover. These Chinese guys are good designing things, if they put their mind into it.

    The one who bought this phone wants it fixed no matter what. Why ? I really dunno.....may be he likes it.....

    Since the collector cannot really fix things, he forward it to me...
    Now you know how I would react....
    I thought I will juggle it a bit, so today I checked and it seems the battery is dead.

    [​IMG]

    [​IMG]

    Stay tuned....
     
    Last edited: Dec 29, 2010
  2. maxpower097

    Well-Known Member

    Feb 20, 2009
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    .......................................................
     
    Last edited: Jan 16, 2011
  3. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    I am going to kick start new year with a battery :D
     
  4. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Replaced mine earlier this year and I'll swear it doesn't hold a charge anywhere near as long. I rarely use the phone but I can only get 4 or so days out of the replacement when I could get over a week from the original. Ah well, $3 off of eBay with 0.99 shipping. Maybe China had that in mind when they put the extra storage place in?
     
  5. haglered

    New Member

    Dec 29, 2010
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    How hard can it be to rig up a charger. Arent most chargers just unregulated power supplies? It's just a matter finding one with a close enough power output and a connector that fits, or finding one that does fit and splicing that onto the charger?

    Yes, No, Maybe? I'm new here but not to cell phones.
     
  6. marshallf3

    Well-Known Member

    Jul 26, 2010
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    There's a ton of universal chargers out there, some as cheap as $3, and they include a boatload of adapters.
     
  7. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    U guys are completely missing my point in this thread..it ain't about chargers. :p

    See the picture.

    [​IMG]

    I unraveled the battery to get my mood going...
    but first see the circle...see what I mean !! No?

    OK...The cross is not marked by me, it was there when I pulled the Insulation. Which means it was marked dead before it hit the shop and yet, it somehow manage to end up in a phone, in Maldives and in My hand.

    Chinese are good, but if they decide to go cheap, they go waaaaaaaaaaaaaay cheap..:D

    Any ways, that was not my aim actually, it is completely different story.
    My aim was to tackle the battery management board since the darn thing decided not to charge. I knew the battery i s OK, it is the circuitry tht faults.

    [​IMG]

    See the pic, I can charge the battery it self, and it holds charge too.
    Now comes the hard part...

    [​IMG]

    I cannot make out what the stupid component is. I can make out the numbering..they are

    8205A & DW01E

    The two 6 pin chip has those two numbers written on it. Now I know one of them is the culprit.
    I did this since, our dear t06afre gave me a SMD identification e book, which I am grateful for.

    But the doggone chip's ain't listed in the ebook either

    So....who can complete this story....for a Happy New Year :D
     
  8. R!f@@

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    I manage to find the 8205A chip .....heee heee heee....
    One more to go.....:D
     
  9. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Keep us informed, sounds like more of a challenge than an easy way out.
     
  10. R!f@@

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    Does any body here have any idea on the type of battery management circuitry used in these type of sells.

    I like to know more about the center pin.

    The chip I figured out was a dual MOSFET. The other one, still no luck.

    If any one have any ideas please feel free to comment.

    The Darn PCB is so small I am having a hard time to make out the trace.

    I guess it's time to take out my bench cam I modified to see small components.
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    I am surprized the battery is (was) actually a real Li-Ion battery and not just a plastic case with some crumpled tin-foil inside.
    Lots of counterfeit parts are absolute garbage.

    Sometimes the center terminal of a rechargeable Lithium battery is a thermistor that changes resistance with temperature to turn off the charging when the charging battery over-heats. The charging circuit (current and voltage limiting) is probably in the phone so the so-called charger is just a simple unregulated DC power supply (usually 5V).
     
  12. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    AFAIK the termistor is used to determine when the charging has finished, the temperature suddenly rises near the end of charging.
     
  13. R!f@@

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    come again?
     
  14. Audioguru

    New Member

    Dec 20, 2007
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    No.
    That is true for old Ni-Cad and newer but still old Ni-MH batteries.
    This one is a "3.7V" single-cell Lithium-Ion that will catch on fire if it gets hot. Normally when charging they don't get hot because the charging circuit limits the current and voltage.
     
  15. R!f@@

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    So you are saying that the battery will heat up and com-bust if I connect it to a 4.2V power supply which can handle 10 amps.

    Wanna see that it is true? :D
     
  16. bertus

    Administrator

    Apr 5, 2008
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  17. Audioguru

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    Dec 20, 2007
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    You must limit the current when charging a lithium rechargeable cell. The cell's datasheet will have a max allowed charging current, listed as xC where C is its capacity rating in mAh's. We don't know what the circuit on the battery is for. It might limit the charging current, limit the discharging current, disconnect the load when the battery voltage drops below 3.0V or disconnect the battery if it charges higher than 4.2V.

    Post a video of your battery blowing up.
     
  18. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    i Have to recharge my sons gameboy battery everyother day. he lost his charger so its the only way until he saves up to buy another.

    It's a 3.7 volt unit and I will swear on a Bible I believe it actually gets colder as I charge it.

    3.9 volts current limited to 100mA. The battery always measures 3.3 volts when he gives it to me, so the game has a voltage reference circuit inside.

    It builds up to 3.6 V in a matter of minutes and stays at 3.8 and .1 amp for about 4 hours. Then the current falls by itself. 3.9 and about 30-40 milliamps is where I stop it. The battery NEVER even gets hot and about half way into the charge - like I said. It gets COLD. not freezing cold but noticably chilled from the luke warm state it starts from.
     
  19. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Yea, the charger for my Makita drills actually has a fan that blows through the battery as it's charging.

    I bought a knock off replacement battery off eBay once and it only lasted a few months before it wouldn't fully charge. The "Bad battery" indication comes up on the charger after about 15 minutes but even at about the 3/4 of a charge it has received it will operate my drills for a decent amount of time. The next time I needed one I got the real thing for not much more and it worked perfectly. I tend to get about a year or so from a battery but they're pressed into some heavy service at times, one is a regular and the other also has a setting to work as a hammer drill. Either one will almost break your wrist if it binds. They were designed for the BL1815 batteries but now I always buy the BL1830s since I get almost twice the usable run time and keep at least one extra around fully charged. Takes about 10 minutes to charge a BL1815, about 20 for the bigger battery.

    http://www.amazon.com/Bare-Tool-Mak...ref=sr_1_1?s=hi&ie=UTF8&qid=1293831881&sr=1-1 is one of them, I bought it bare since I already had a charger and keep batteries around.
     
  20. R!f@@

    Thread Starter AAC Fanatic!

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    Aaaaaaaaaaah! You like that...wouldn't ya? :D
     
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