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Thursday, December 31, 2009

UPS And PC Power Supply Parts Bonanza

A bit of salvaging of some old computer power supplies and UPSs (most of which were found in alleys or roadside on bulk trash days, over the last few months, but sat "intact" until now due to lack of time) netted me several pounds of parts (not counting the toroids or transformers!), including the stuff shown in the pics below.

Bunches of small value caps, diodes, zeners, transistors, mounting screws, heatsinks and clips (and thermal pads), and lots of resistors not yet taken off the boards (not in pic), several TL431A and some LM317

Some very old 100V+ Vce type transistors in PNP and NPN, off some boards from a Sony VTR (I never saw the VTR, just the boards)

They'll be used to replace some lower voltage 2222's on my 2QD so I can up it to 48V+ usability.

Bunches of small signal transistors, 50V Vce types, a bit better than the 2222 but not much.

A few beefy dual-diode (common cathode) units, one of them up to 40V at 50A!

Also about three times that many smaller TO220 versions of these, mostly in the 40V 3A range. All can be used with heatsinks to parallel unequally-charged battery packs in a pinch.

Of course, there are lots of large caps, too, in low and high voltages, and many form factors.

MOSFETs; lots of them, too, though mostly lower-voltage types, and generally fairly high RDSon.

Some IC's, too. Optoisolators, LM339 and LM324 chips, other single or double op-amp chips, some logic chips (74x series), some "house branded" chips in the UPSs which probably means they're ROMs or pre-programmed MCUs. Some standard PWM SMPS control chips, might be adaptable as controller chips.

Transformers, connectors, toroids, cables, wire, heatsinks, switches, LEDs, etc. Fans, too, but the fans are all defective. They might have usable hall sensors in them, though, as long as I don't need linear sensors (they're more likley to be switching types).

Most of the desoldering was done by carefully using a very small propane torch to heat the thru-hole lead areas, while gently tapping the PCB on the bench (outside, so any fumes would not suffocate me). Some things required a solder-sucker and regular soldering iron.

I should be able to build up my other 2QD controller out of what's there, plus have plenty left over for other projects for a while to come, such as a BLDC controller.

There are LOTS of electronics that have all this stuff salvageable if you have time to do it. I generally spend only a minute or two at a time, over days or weeks, and end up with what looks like "Christmas at the parts store". :) Even if only half the parts worked when done, it'd have saved me enough money it'd stil be worth it.

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