From: Boby <sup.bio_at_club-internet.fr>
Date: Tue, 16 Sep 2008 18:53:30 +0200

Hi !
  ----- Original Message -----
  Also, the (-) of the charger shares the same ground as the screw
holes, the metal frame of the USB jack, and is also grounded to the
headphone common wire. With a continuity tester (available on pretty
much any digital multi-meter) the wire of the DC jack that connects to
all of those is the (-). One of the other DC connections would be (+).
The third DC connection is probably connected to the (-) and can be
found out with then multi-meter.
OK tnanks a lot, I will bring back my H340 to the technician in my high
school tomorrow. I'm sure he has such a multi-meter.
Just one more question : this technician already soldered 2 out of the 3
points that could be soldered to the DC jack inside of the iriver. He
things he did it right for those two (le + to the + and the - to the -)
but didn't know where to solder the third one. If, when we chek this two
wires with your method tomorrow, we confirm that the - is linked to
the -, can we try to connect my H340 to the DC charger ? In other words,
I don't understand why there are 3 points ? Is the third one unuseful
??? Will it damage my H340 if the first and the second one are correct
but the third one linked to nowhere ? (il fact, the piece of metal
needed for the third one is broken and he didn't find it inside of my
h340)

The second method...
   Before you plug in the DC charger you may want to cut one of the
wires and install a lightbulb of the same voltage rating of the charger.
Just to make sure I'm understood about the lightbulb wiring, it'll be in
series with the charging circuit. If the lightbulb comes on at full
brightness that means the DC jack is wired backwards. Most
semiconductors act like a forward biased diode when reverse polarity is
applied. The lightbulb is not only an indicator but also as a current
limiter to prevent a high reverse current.


sounds to me far more difficult. You wrote "may". If I understood
properly, if the first one works, we don't need the second one, do we ?

Thanks a lot

Boby


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Received on 2008-09-16