Well i have an asus laptop charger (19v 4,74a)for repair and it seems it is going to beat me
Charger was dead...One of the diodes in diode bridge rectifier failed and killed the charger...I have replaced:
-diode bridge
-input filter inductor before diode bridge
-blown big primary filter cap(was 100uf 450v ,i put 100uf 400v as didn`t have other at the moment)
-blown fuse
Now when i turn the adapter on it gives 19,4v for a second and than turns off...voltage just drop at the output...but...
If i connect load(for test purposes put two 12v fans in series ) and then turn adapter on,it works well and it is steady at 19,4v...As soon as i disconnect the load charger turns off...reconnecting the load won`t trigger the charger to turn on again...
I spent a lot of time here and have tested all componnents in feedback circuit and it seems to be ok...
I`ve noticed that when there is no load, and no output respectivly ,voltage on a primary filter cap is oscillating from 506v to 515v which seems to be a little higher than it should be i think...
Any toughts ?
Charger was dead...One of the diodes in diode bridge rectifier failed and killed the charger...I have replaced:
-diode bridge
-input filter inductor before diode bridge
-blown big primary filter cap(was 100uf 450v ,i put 100uf 400v as didn`t have other at the moment)
-blown fuse
Now when i turn the adapter on it gives 19,4v for a second and than turns off...voltage just drop at the output...but...
If i connect load(for test purposes put two 12v fans in series ) and then turn adapter on,it works well and it is steady at 19,4v...As soon as i disconnect the load charger turns off...reconnecting the load won`t trigger the charger to turn on again...
I spent a lot of time here and have tested all componnents in feedback circuit and it seems to be ok...
I`ve noticed that when there is no load, and no output respectivly ,voltage on a primary filter cap is oscillating from 506v to 515v which seems to be a little higher than it should be i think...
Any toughts ?
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