I'm still trying to repair my Kinder AFB+. I first replaced the electrolytic capacitors...No change. Then I replaced the transistor...Fixed part of the problem. Next, I'll replace the integrated circuits.
This part had me baffled. How the heck do you remove those things??!! You can't keep the solder hot on all those wires at the same time! I found the answer. Maybe this is old hat to you folks who are accustomed to working with electronics, but I thought I'd post this in case it's a help to somebody out there.
I didn't watch the video, but there are some alloys that you can buy with low melting points. Here's one example - http://www.zeph.com/lowmelt.htm
If you're removing a part and don't care to save it, then you could also take approaches like cutting off the pins. I don't recommend it, but I've seen it done.
Parallax Semiconductor is a company that mostly serves hobbyists and the educational market, and runs some forums that attract a helpful crowd. They also have educational materials for sale along with ebooks that you can download for free. Anyways if you visit their forum and ask electronics questions you will probably get some good advice. Just try to ask in the right forum - e.g. http://forums.parallax.com/forumdisplay.php?89-Builders is probably an o.k. place.
I haven't done any electronics since the 70s, but there were two ways to desolder ICs then: - a) you could buy a metal attachment for soldering irons that was the same size and shape as an IC and you pressed it against all the pins simultaneously. b) you use a low-power blowtorch with a fanned out flame - it melts the solder in a second or two and you quickly pull the IC out and the torch away before it does too much damage to the rest of the circuitry. This idea probably works best if you're building your own gear - I'm not sure how severe the problems would be with high-density circuitry.
Or if you don't mind destroying the IC, you can snip the legs, then desolder them individually.
Of course, if it's soldered both sides of the circuit board, you're in trouble! (I haven't watched the video either)
I never used solder-wick, but that reminds me you can also get solder-suckers that are a bit like blackhead/zit removers. ----------
Andrew. ----------------------------------------- Those who are tardy do not get fruit cup.
Last Edited by on Jul 10, 2011 4:31 AM
Are you even going to be allowed to purchase a replacement IC from Kimder? If it is one of his custom ones?
When/if you use solder wick, be patient. Don't try to do it all at once. Too much heat = bad. Remove as much as you can and then from the underside, heat a single pin at a time and make sure it is free - continue moving it as the solder re-hardens. If there isn't much solder to begin with because you did a good job with the solder wick and/or solder sucker - the pin won't re-bond or will with such small area that you can break it loose with a gentle push from a sharp tool. Repeat for all the pins........
If you're trying to repair the AFB+ without knowing how the circuit works or what individual components do, and you're instead just grasping at straws, your chances of success are greatly diminished by the chance of screwing something else up while you hunt for a needle in a haystack. ---------- /Greg
Thanks for the tips, Greg. I will desolder the underside first, but with eight pins, it will be difficult (if not impossible) to assure the wires are free. The technique in the above video solves this problem beautifully.
I e-mailed Kinder asking to buy the parts that could have been blown. I never heard back from them.
I don't know anything about electronics, but I know how to Google. According to what I've read, the electrolytic capacitors could have been damaged (The other capacitors should be OK.), the transistor could have been damaged and the ICs could have been damaged.
I ordered the capacitors. They didn't help. Then I ordered the transistor. It fixed part of the problem. Now I'm waiting for the ICs to come in the mail. Wish me luck.
I got the numbers from all these parts and found where to order them. Among many other things, the AFB+ has three electrolytic capacitors, one transistor and seven ICs. These parts are amazingly cheap. I believe the cheapest was .19 and the most expensive was a little over a dollar.
I do know how to solder, however it was just the past week or so that I've ever even heard of solder wick. Neat stuff!! I don't like the soldering irons that are intended for small work. They are low wattage and can spread the heat too far before the solder gets hot enough. I have a big ol' Weller 240/325 watt soldering gun and I ground the tip to the right shape. This thing will heat the wires and solder IN NO TIME, so the heat will not spread throughout the whole dang unit before the parts get soldered.
Good idea. I'm bound to have some scrap laying around somewhere.
I've figured out "PCB" (printed circuit board), but I'm still trying to figure out "pads." Is that the black things the ICs mount atop of? If "yes", there are no pads on the board in the video, but there are in my unit. If "no"...well it doesn't matter....I'll be careful.
Hmmm...Are "pads" the little metal parts with the holes for the wires to go through?
Last Edited by on Jul 11, 2011 3:21 PM
Sorry - I mean the metal on the circuit board that you solder the parts onto. (http://www.pwtpcbs.com/glossary/pad.html) I've seen people lift these off of the printed circuit board. If you have some scrap maybe you could see if you can get one to come off just to see what I'm talking about, and how delicate they are.
I'm assuming that there are surface mount components in the kinder since you linked to the above video.
I should have mentioned to that you might want to search for information on hot air reworking tools. Given that you're only fixing a single unit this is probably a bit too expensive. But it wouldn't hurt just to look for information.
Yeah, I guessed right after my "Hmmm" above. I'm betting people have lifted those off because of those stinking low-wattage soldering irons. I believe I may have lifted one off with my big Weller(Not on this project.), but that would have been due to a combination of poor lighting and the shape of the tip. I've since modified the tip.
Oh, yeah...Plenty of surface mount stuff.
Last Edited by on Jul 11, 2011 3:52 PM
Another thing that you might do is see if there's anyone in your area with a SMT (surface mount) rework station that could help you out.
In some areas there are places where you can go to get access to this sort of thing - e.g. http://techshop.ws/ (I'm not sure what this particular place has since I've never been there) Basically the place where people who read Make magazine go to make things.
I got the ICs in the mail and discovered that on the AFB+ circuit board, they do not solder onto the board. They merely plug into sockets that are soldered onto the board. (I told you I don't know nuthin' 'bout 'lectronics.)WHAT A WORK SAVER!!
Anyway....IT'S FIXED!!!!!!!!!!!!! IT WORKS!!!!!!!!!
For curosity's sake, I wish I knew which part or parts really had to be replaced. It doesn't matter, really, as far as cost is concerned. They cost next to nothing. I might have saved around 6 bucks on shipping, though.
Now...Anybody want me to fix your amp?.....Hey, Where y'all goin'? Come back.....
