Help identify replacement for burnt out component

The silkscreen says L1, so it is pretty likely a choke. You may have to remove L1 and put it under a magnifying glass to see if you can identify labels. 

stanto You are correct.  It is an inductor.  The "L1" label on the PCB helps validate that.  You are also correct in that the current that caused that damage may have damaged other components.  AND... it might not have - because the rest of the PCB looks really clean.

As to the output voltage... those little chargers have terrible regulation.  I have some that have very high unloaded output voltage levels - relative to what they are supposed to run at.  When they are connected (loaded), the voltage comes down.  If your buzzing is high pitched, you just may be hearing the power supply switching.  I have a couple of USB power supplies that I can hear - if the house is really quiet (which is rare).

Have fun on the repair. 

hello. i would start by checking the TO3 transister, L1 looks like a noise filter, if L1 measures like a short and transister does not have shorts i would power it up 

It is... melted, there is nothing identifiable on it.

I'm used to a high pitched sound, but this was like a loud, angry bee/hornet thats low pitched.

I thought that it may be an "unloaded" issue, but the diodes seem to read values both ways and that implies damaged to me.

I may try sacrificing another power supply to see if I can recover some parts and make something that works.

This thing is not powering up, your advice is a little confusing.

I salvaged an inductor and diodes from another power supply. Unfortunately it still doesn't function.

Its supposed to charge batteries, it lights a green led, but the secondary led when a battery is connected does not light up, and a meter on the points to the battery doesnt increase so another component has likely failed. Sadly this is one for the bin.

Hi  stanto 

the most important info we need is the designator, the name of the IC. And the 2. is the big transistor - the 3pin black block, this looks like a MOSFET.

If you know which IC you have you can rework from the PCB to the schematic, using a datasheet from them.

I think the MOSFET as well the IC where gone.

stanto You gave it a good try.   If the simple fix wasn't enough... your time is more valuable on another project or endeavor.  Knowing when to call "No joy" is also a skill. 

What is the numbers on the TO3 transister or FET,

were the diodes that you pulled out faulty