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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Sharp notebook power supply
Does anyone know the connector polarity for a Sharp A250 notebook please? I
have been given one without the external power unit and I want to test it before buying a new PS. The notebook label specifies an EA-J02V 22v 1.8Amp ac adaptor, that connects with a 3.5/1.35mm connector. I need to know is the center pin positive or negative to chassis? TIA Malcolm L Somerset UK |
#2
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Sharp notebook power supply
Malcolm,
You could try with a voltmeter. Check for continuity between the pins and some metal part of the chassis. The pin that has continuity will be the negative one. Another way that could work is to test the pins with the voltmeter set to diode test. Put one lead on each pin, then reverse them. If you get about 0.600 one way, and open reading the other way, then your positive pin is going to be the one with the red voltmeter lead when the voltmeter reads open. If you get values that do not match the above, then I would post them here before trying to plug it in. Got2Go "ML" wrote in message ... Does anyone know the connector polarity for a Sharp A250 notebook please? I have been given one without the external power unit and I want to test it before buying a new PS. The notebook label specifies an EA-J02V 22v 1.8Amp ac adaptor, that connects with a 3.5/1.35mm connector. I need to know is the center pin positive or negative to chassis? TIA Malcolm L Somerset UK |
#3
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Sharp notebook power supply
Thanks for the reply, Got2Go,
The outer is definitely connected to chassis (I guess the shell of ext video connector is chassis, everything else is plastic!) Putting v/m on diode test reads 3.48 with positive lead connected to inner pin rel to chassis and 1.06 with negative lead connected. Not easy to judge as there must be a charger circuit between the 22v input and the 14v internal battery. There may also be a reverse volt protection on it as well? I'm a bit nervous at taking a gamble! Malcolm Got2Go wrote in message news:QUjbc.5516$zh.4049@fed1read07... Malcolm, You could try with a voltmeter. Check for continuity between the pins and some metal part of the chassis. The pin that has continuity will be the negative one. Another way that could work is to test the pins with the voltmeter set to diode test. Put one lead on each pin, then reverse them. If you get about 0.600 one way, and open reading the other way, then your positive pin is going to be the one with the red voltmeter lead when the voltmeter reads open. If you get values that do not match the above, then I would post them here before trying to plug it in. Got2Go "ML" wrote in message ... Does anyone know the connector polarity for a Sharp A250 notebook please? I have been given one without the external power unit and I want to test it before buying a new PS. The notebook label specifies an EA-J02V 22v 1.8Amp ac adaptor, that connects with a 3.5/1.35mm connector. I need to know is the center pin positive or negative to chassis? TIA Malcolm L Somerset UK |
#4
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Sharp notebook power supply
If the outer shield/ring/shell of the power connector is tied to chassis,
then that is your ground and the pin is the positive. This is the most common configuration. Your vm readings also seem to support this. Plug away. Center pin=Hot + Got2Go "ML" wrote in message ... Thanks for the reply, Got2Go, The outer is definitely connected to chassis (I guess the shell of ext video connector is chassis, everything else is plastic!) Putting v/m on diode test reads 3.48 with positive lead connected to inner pin rel to chassis and 1.06 with negative lead connected. Not easy to judge as there must be a charger circuit between the 22v input and the 14v internal battery. There may also be a reverse volt protection on it as well? I'm a bit nervous at taking a gamble! Malcolm Got2Go wrote in message news:QUjbc.5516$zh.4049@fed1read07... Malcolm, You could try with a voltmeter. Check for continuity between the pins and some metal part of the chassis. The pin that has continuity will be the negative one. Another way that could work is to test the pins with the voltmeter set to diode test. Put one lead on each pin, then reverse them. If you get about 0.600 one way, and open reading the other way, then your positive pin is going to be the one with the red voltmeter lead when the voltmeter reads open. If you get values that do not match the above, then I would post them here before trying to plug it in. Got2Go "ML" wrote in message ... Does anyone know the connector polarity for a Sharp A250 notebook please? I have been given one without the external power unit and I want to test it before buying a new PS. The notebook label specifies an EA-J02V 22v 1.8Amp ac adaptor, that connects with a 3.5/1.35mm connector. I need to know is the center pin positive or negative to chassis? TIA Malcolm L Somerset UK |
#5
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Sharp notebook power supply
Got2Go wrote in message news:05nbc.6257$zh.3266@fed1read07... If the outer shield/ring/shell of the power connector is tied to chassis, then that is your ground and the pin is the positive. This is the most common configuration. Your vm readings also seem to support this. Plug away. Center pin=Hot + Got2Go Success! you were right. Thanks for the moral support I needed to switch on!! Now for the next problem, finding out why the mousepad isn't working............... Thanks again. Malcolm |
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