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stsmytherie

Member
2005-11-08 6:42 pm
Vermont
  • #1
    Hi folks. Long time member who gained a lot of knowledge from this forum over the years, just finally getting around to doing a bit of talking.

    Started messing around with DIY audio back in the 90s, but took a loooong break when kids arrived and work commitments heated up and we moved across the country a couple times.

    My successful projects so far include:

    Dynaco ST-70 and PAS-3 restoration and modification
    Pass Bride of Zen
    Bottlehead Foreplay
    NY Audio Lab phonostage restoration (wish I still had this)
    Conrad Johnson PV5 restoration and modification (not worth the effort and expense IMHO)

    Recently built up a pair of Frugalhorn Lites with FF85wk drivers, and have sort of fallen down the rabbit hole of messing with vintage CD players with swing arm mechanisms and TDA154x DACs.

    Feeling like it's time to finally build a proper amp project. I have some unfinished S.E.X. amps in a box somewhere, but I'm reading up on what Mr. Pass has been doing since I was last actively doing projects. Leaning towards an ACA and then maybe a Aleph J.

    Rest of current system is:

    VPI HW19 Mk2 + Moerch UP4 + Benz Glider
    Magnavox CDB460 (stock at the moment, a second one is currently being recapped)
    Nakamichi SR-2A
    Spendor SP2/2
    FH-Lites

    Cheers all. Thanks for being here.

    * * * * *

    PS: family member surprised me with the gift of a hot air rework station. I'd love to try working with SMD components. Any suggestions for a cheap, simple, but useful first-time SMD project?
     
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    stsmytherie

    Member
    2005-11-08 6:42 pm
    Vermont
  • #6
    sthcoaster said:
    If it’s A smd project you are after and you like playing with TDA1541a have a look at RyanJ’s Distinction 3 boards with Signal attenuation and 50hz DEM, coupled with his I2S>>simultaneous board (also smd)

    Welcome from just lurking
    Click to expand...

    Funny enough, I was looking at exactly that set of boards and wondering whether I should get some practice before trying. No harm in diving right in I suppose.

    Cheers
     
    sthcoaster

    sthcoaster

    Member
    Paid Member
    2016-03-03 9:46 pm
    Washington DC
  • #9
    stsmytherie said:
    Funny enough, I was looking at exactly that set of boards and wondering whether I should get some practice before trying. No harm in diving right in I suppose.

    Cheers
    Click to expand...

    I’m not expert but have had some success though I do find myself reverting or finishing with a very fine solder and fine point iron. For me I have found the hardest to solder are the “large” smd can capacitors (Oscons etc)

    Start with a good quality solder paste - use sparingly. Low air so you don’t blow everything off the board. I find If you preheat the board a little the paste will go on pads better. Work a section of the board at a time.
     
    Tubelab_com

    Tubelab_com

    Member
    2005-07-14 4:18 pm
    West Virginia panhandle
    www.tubelab.com
  • #10
    Get an old junk SMD board and practice taking parts off without making the board smoke. I used a nice Hakko at work for years, but work ended 5 years ago.

    I purchased a $99 hot air station a few months ago and it took some getting used to. Start with small parts like resistors and SOT 23 transistors, then work up to bigger stuff. The cheap hot air station will not get the board hot enough over a large area to take off a large BGA chip without collateral damage, but that's OK. I don't need to do that. I used a dead computer motherboard for this exercise, as all of it was headed for the recycler anyway.

    After getting the feel of it, putting parts on was far easier.

    I used a piece of .080 aluminum for holding the board. I put a small dab of Kester EP256 solder paste on each pad using the syringe it came in (Amazon). Then I placed all the parts in the solder paste with tweezers. I turned the hot air station on without any restrictor nozzle using the same settings I used for removing parts without burning boards. I heated up the aluminum panel first, then placed the board on top of it, and proceeded to move the rework nozzle slowly all over the board until all parts were soldered. The solder will turn from a dull grey to shiny silver when it reflows. Once all parts are reflowed, I carefully place the aluminum panel with the board onto a large heat sink for cooling.

    You don't need to place all the parts at once. You can place solder and parts on a small section of the board cook them, let cool, then place solder and parts on another section. It's OK to reflow the first set pf parts when placing the subsequent parts.

    It is easier to place the multi pin parts first. Things like QFP's and QFN's are easier to deal with when there aren't a bunch of small parts nearby.....at least for me with my shaky hands.

    Another possibility is to place all the solder and parts, then put the board on a hot plate (Amazon) turned up to about 500F until all parts reflow, then CAREFULLY move it with pliers to the heat sink for cooling. I prefer this method when there are lots of parts to solder.
     
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