[quote] Earphone jack not working [/quote] is not precise enough but a common issue seems to be the small headphone icon is no more displayed when connecting a headphone. This may happens for 2 reasons:
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- Some male jacks does not respects dimensional specifications and are not properly recognised. Either N8 says "Device not supported" or nothing happens. Try with another headphone.
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- Some users reports the earphones are not recognised following a chock. User should remember their N8 felt on the ground.
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The female connector on the printed board is not the root cause, neither is the small flat cable. It seems there is a sensitivity on the main board (or "G fuse" set for purpuse) that locks the feature. I checked on a device having the problem and all points described below were ok.
+
The female connector on the printed board is not the root cause, neither is the small flat cable. It seems there is a sensitivity on the main board (or "G fuse" set for purpose) that locks the feature. I checked on a device having the problem and all points described below were ok.
-
The phone detects a headphone via 2 informations.
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The phone detects a headphone via 2 informations.
+
1) The female connector on the N8 features a switch that activates circuitry only if a jack is introduced. This saves power. Introduction of a dummy jack in plastic activates the switch that power-on the circuitry (i.e. the microphone input receives 2.4v) but a headphone is not detected by the N8.
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2) Actual identification of the type of headphone is based on resistance between ground and microphone input:
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- short-circuit (~0 volts) = just a headphone
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- medium resistance (i.e. resulting in ~1.2 volts) = headset with a mike.
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+
- short-circuit (~0 volts) = just a headphone
+
+
- medium resistance (i.e. resulting in ~1.2 volts) = headset with a mike.
Using a 3 poles standard jack cable we can check that: Introducing the jack, it short-circuits ground and microphone tip and the small headphone icon is displayed.
+
Using a 4 poles jack allows to check the voltage on the microphone tip.
The jack on the printed board features a switch for physical introduction detection but it seems not connected: Introduction of a dummy jack in plastic activates the switch but is not detected by the N8.
+
[quote] Earphone jack not working [/quote] is not precise enough but a common issue seems to be the small headphone icon is no more displayed when connecting a headphone. This may happens for 2 reasons:
+
- Some male jacks does not respects dimensional specifications and are not properly recognised. Either N8 says "Device not supported" or nothing happens. Try with another headphone.
+
- Some users reports the earphones are not recognised following a chock. User should remember their N8 felt on the ground.
-
The phone detects introduction of a jack by temporary short-circuits between ground and microphone input (purple link on the picture). A small headphone icon is displayed.
+
The female connector on the printed board is not the root cause, neither is the small flat cable. It seems there is a sensitivity on the main board (or "G fuse" set for purpuse) that locks the feature. I checked on a device having the problem and all points described below were ok.
-
Identification of the type of headphone is based on resistance between ground and microphone input:
+
The phone detects a headphone via 2 informations.
+
1) The female connector on the N8 features a switch that activates circuitry only if a jack is introduced. This saves power. Introduction of a dummy jack in plastic activates the switch that power-on the circuitry (i.e. the microphone input receives 2.4v) but a headphone is not detected by the N8.
+
2) Actual identification of the type of headphone is based on resistance between ground and microphone input:
+
- short-circuit (~0 volts) = just a headphone
+
- medium resistance (i.e. resulting in ~1.2 volts) = headset with a mike.
-
short-circuit = pure headphone
-
-
medium resistance (~1 kohm) = headset with a mike.
-
-
Some male jacks does not respects dimensional specifications and are not properly recognised. Either N8 says "Device not supported" or nothing happens (no headphone icon).
+
Using a 3 poles standard jack cable we can check that: Introducing the jack, it short-circuits ground and microphone tip and the small headphone icon is displayed.
+
Using a 4 poles jack allows to check the voltage on the microphone tip.
The jack on the printed board features a switch for physical introduction detection but it seems not connected: Introduction of a dummy jack in plastic activates the switch but is not detected by the N8.
The phone detects introduction of a jack by temporary short-circuits between ground and microphone input (purple link on the picture). A small headphone icon is displayed.
Identification of the type of headphone is based on resistance between ground and microphone input:
short-circuit = pure headphone
medium resistance (~1 kohm) = headset with a mike.
Some male jacks does not respects dimensional specifications and are not properly recognised. Either N8 says "Device not supported" or nothing happens (no headphone icon).