Hi,
>
> Have one Dell Laptop AC Adapter that is emitting hissing sound. A
> physical checkout does not reveal any burnt parts.
>
> Model:PA-1900-05D PA-9 Family
> Manufacturer: LiteOn
> Input: 100-240V 50-60Hz 1.5A
> Output: 20VDC 4.5A
> Marking "CN-06G356-71615-432-061F Rev L04"
>
> Any schematics that are available?
>
> All advise is welcome. Thanks
> ???SeventhPrince
It's a switchmode power supply so normal troubleshooting techniques apply. Check for high ESR electrolytic capacitors, bad connections, shorted components, etc.
See the SMPS repair guide at the sites below, or as someone else said, order a replacement.
WARNING: Line powered switchmode power supplies can be deadly, make sure you understand the safety issues.
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