Re: IRF510 #alignment

Tisha Hayes
 

A suggestion on bad components removal from a circuit board. Unless you feel compelled to completely salvage the old part, cut the leads off the part and physically remove it first.

Then, apply a few drops of liquid rosin and use a hot soldering iron to melt the joint and lift the stub of the component lead out with the side of the soldering iron. If it resists then while the joint is molten, bang it gently on the table and the lead will fall out the bottom of the hole.

You can do this if you do not have a desoldering station that applies suction to remove the solder. Also, you are not digging around on the soldering pad or trace that can cause it to disbond from the fiberglass on the board.

I worked as a bench tech for a few years in college, doing component level replacement on high density circuit boards covered with DIP chip packages. I literally removed thousands of IC's, resistors, caps, transistors, connectors, from circuit boards. The times where I lifted a pad or tore off a trace I could count with the fingers on one hand. You just get very good at doing it, you can work fast and there is no stress when confronting removing lots of parts. (some of the things we had in for repair had been damaged by lightning and sometimes yI had to replace ten or fifteen DIP 16 and DIP 40 chips on one board (the boards had 80-200 chips on them)).

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As far as counterfeit components, yes, I definitely have seen that too.. particularly in parts originating out of one particular country that magically can supply components very cheaply (the guess is yours, I am not going to get political about it). What I have found that is very useful is the Peak DCA75 (made in the UK, accept no substitutes). It also works great for testing batches of transistors to match them when working with push-pull amplifiers. I have seen some pretty wide variances in components and a few "guaranteed good" components from "that country in question" that were completely different parts or just bad-bad.

So a big thumbs up to www.peakelec.co.uk   they make excellent pieces of kit with capabilities that are amazing. That applies to all of their devices (I own four or five of their little testers for a variety of purposes).
--
Tisha Hayes, AA4HA
Sr Engineer, 4RF Inc.

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