I bought a Black & Decker Charger to charge the 18V NiCd battery packs that came with a B&D charger and a dismal, minimalist clip-on charger. It came from eBay and seemed to be the real thing. It worked great for a few charge cycles - like maybe as many as six. Then dead, nada, no go.
Inspection
I opened it up with a T15 security bit and started probing. I traced the continuity of the AC path to the bridge diodes and found AC voltage from terminal Y3 wasn't getting through the common mode choke (located across from Y4). And F1 was open so there was no connection to Y4.
There was a dark spot on one of the choke windings. It appears there was a defect in the winding insulation that caused the choke to short out the 120VAC line input and blow the fuse (fortunately!). There is a clear insulating coating (typically lacquer) on the copper colored winding.
Replacement Parts
I found the fuse on Newark Electronics, Multicomp Pro MST 2A 250V Slow blow, stock #95M6783.
The closest common-mode choke I could find was the Kemet 2A 1µH, Newark #SC-02-10GS.
Shifting Gears
It seems the choke is not as "in stock" as I was led to believe, so I rewound the toroid myself. I found one wire had a nick in the insulation, the other wire was broken as I unwound it. I had an assortment of solid 22 AWG PVC wire so I used two strands of that. It was a little thicker than the winding wire so I didn't quite get the 8 turns in, but I think it will do for an hour here and there (I already converted the other battery to lithium). I soldered the new fuse and rehabbed coil into place and powered 'er up. The red LED came on briefly, and there was roughly 14VDC (as I recall) x 2 on the other side of the bridge diodes.
Conclusion
I inserted the NiCd battery pack and the red LED went to blinking (Charging) until it went solid (Charged) an hour or so later. Battery voltage was checked periodically and it seemed appropriate. I declare it fixed.
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