[OT] Dodgy electrolytic in 3COM hub

Beauiful photo of this swelled up electrolytic capacitor. :-) What is that digital photo camera? The 7 legged "transistor" is a efficient regulator IC switcher that down converts input voltage to specific voltage. Good to about 1 amp or so with little heatsinking. That whistle is the noise of that regulator switcher it works at high freq. They runs too high freqs to hear but when they get loaded down or bad caps, they decrease in PWM (more ON time) trying to keep voltage up (more power transfer, then u can hear the noise. The swelled up cap is already GONE btw. I have seen all descriptionss of failed caps. 1. that looks fine and clean but ESR is totally gone, are *most common*, hence ESR meter is a must. 2, leaking either end, some types of electrolytes is corrosive & stinky to heavens (1 year old rotten fish) when heated. 3. Swelled up or split top or uncorked rubber bung. 4. Bad cap that tests good but no good, that's rare few and diffcult to find. 5. Plain exploded spewed brown fluff and shreds of spiraled ribbons everywhere. Dipped blue or yellow disks caps (1KV and up) does vent cloud of pink smoke. I was amazed when I saw it go. Cheers, Wizard