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Re: [softrock40] Re: USB Power Supply Voltages off.

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  • Thomas Bewick
    Greetings Bob, The education has been worth the problems. Again I do thank you for all you advice. As a nurse with no experience in electronics I gladly accept
    Message 1 of 27 , Apr 29 1:05 PM
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      Greetings Bob,

      The education has been worth the problems.
      Again I do thank you for all you advice. As a nurse with no experience in electronics I gladly accept your advice and am glad to have the education in electronics in the 'school of hard knocks". From what I know of lead it is not a risk at all unless it is directly ingested and the regulations of some of this stuff is ridiculous. They now regulate the removal of lead pain in the states with really crazy guidelines. At least if you do it yourself you don't have to follow them.

      For the USB power stage I have gone a head and ordered new 475k caps, a new voltage regulator, and some MG Flux cleaner from digikey ( I have enough SMT caps left over to replace them all with new). Not that I think the parts are bad at all since you say they very rarely fail, but so I can remove all the parts in the usb power stage along with all traces of solder, clean it well, inspect it and put it all back in without using flux and using leaded solder on clean pads with clean parts to hopefully eliminate any bad connections. With the money, and especially the time, I already have invested already I figure it is at least worth a try to save the board.  It will be a while before the parts come in and I get it done but I will report back. Thanks again.

      By the way beautiful wedding you put on over there. I watched live at work as much as I could last night, My grandfather is British coming over from Seaham harbor as a boy in the 1920's to the states. My call is a vanity one to show off my British heritage as a Bewick.

      73's
      Tom
      N2BEW

      On Fri, Apr 29, 2011 at 3:27 AM, g8voip <g8voi.reeves59@...> wrote:
       

      Hi Tom,

      Sadly the vast majority of the videos around on SMD soldering that I have seen appear to produced by, with no disrespect 'hobbiests' more keen to show off their own skills rather than necessarily being of any real practical use to those looking for guidence.

      Some of the techniques suggested take a lot of practice to perfect and certainly are not to be recommended for a first attempt on a 'real' project unless you are prepared to make a real mess of it!

      All of the components used in the SoftRock kits can be easily soldered conventionally using nothing more than fine gauge solder and a conventional iron. Beware that sometimes too finer bit can be a problem as it is not possible to get enough heat into the pad to make a good joint, particularly on connections to ground. I just use a standard 45W Weller TCP iron and a conical bit.

      There is sufficient flux contained within the solder , so no additional flux is normally required. The only components that seem to cause some difficulty are the Si570 and perhaps the small 3.3v regulator. A liquid flux pen might help with the Si570, but personally I have never found it necessary.

      You commented using a liquid flux pen, usually the flux drys very quickly and leaves little or no residue after soldering. The big problems come where people use forms of flux paste etc. These often harden when heated into a really nice insulation layer between the PCB pads and component legs :)

      I personally believe a lot of the soldering problems stem from the use of lead free solder. Whilst I have to suffer it at work, I would never contemplate using it at home, really not fit for the purpose and the reason the reliability of manufactured electronic equipment has plummetted in the past 5 - 10 years.

      Sad thing is in the original research done, the guy who recommended stopping using leaded solder actually has now been shown to have got his calculations wrong and had a decimal point in the wrong place, so actually little or no risk at all! Likewise the fact that where reliabiity is concerned, military and avionic use, leaded solder has continued to be used.

      Everyone, rightly has their own opinions as to the best method and techniques on how to solder. It's something you need to work on to perfect and fine the approach best for youself.

      The advice I offer is simply based on my own experience as a hobbiest and professional electronics engineer for more than 36 years.

      73, Bob G8VOI


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