jw May 8 2001, 12:45 pm show options

Newsgroups: aus.comms.mobile, sci.electronics.repair,
alt.cellular.nokia
From: jw <[email protected]> - Find messages by this author
Date: Tue, 08 May 2001 21:46:08 +1000
Local: Tues,May 8 2001 12:46 pm
Subject: Inside a Nokia Charger
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I've just successfully repaired the car charger of my Nokia 3210.
I tried searching both the web and Usenet for the current or
voltage specs, but all I found were other people asking
the same questions. So I'm posting my findings to those groups.


PROBLEM:
1. I plug the charger into my phone and car cig. lighter.
2. I turn the ignition key and the phone lights up and shows
"Charging".
3. Everything seems ok for about a minute. Then the phone says
"Not Charging" and the charging indicator stops moving.
4. If I disconnect the charger or turn the key to "Off", then
reconnect or turn it on, it says "Charging" for a few seconds,
then goes back to "Not Charging".
5. The phone gets a small amount of charge, enough to make calls with,
but charger won't fill the battery.


The phone charged perfectly ok with the AC mains charger.
(A genuine Nokia ACP-7A. The car charger was an unbranded
non-Nokia accessory bundled with the phone by the dealer.
The only markings on it was a sticker saying "3210/6110".)
I didn't realise there was a problem until after six months
after I had bought it, when my phone went flat while I was
in my car.


I tried the phone with another (supposedly identical) car charger
which came with an identical 3210 kit bought from the same place
a few weeks after mine. This worked perfectly.


So I disassembled both chargers to compare their circuitry.


The charger consists of a single IC chip with a few other parts.
The IC had CP34063 printed on it. A web search for 34063
revealed this to be an MC34063A, a fairly common Switch Mode
DC-DC Voltage Converter. The datasheet can be downloaded from
www.fairchildsemi.com/pf/MC/MC*34063A.html
and many other places.
Long ago in a far off galaxy.........

A poster to this group told how he'd fixed a car charger (upped it's
output current from 450mA to 500mA by adding a resistor........


"The main difference between the 2 chargers was that the other
one had an EXTRA 3.3 ohm resistor in parallel with the .33
ohm one. This was solder onto the printed side of the circuit
board, and had the effect of raising the limit by 10%.
To 500 mA, I think.

So I soldered a 3.3 ohm resistor in paralell with the 3.3 ohm and now
it works."

Just to add my 2pennoth i've just fixed mine, adding the 3.3K in
parelllel didn't do it, but replacing the original with 3.3K did.



› See More: Modifying a car charger