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40 pin soic sockets.. Do they make them?

Discussion in 'Electronic Repair' started by Michael Kennedy, Jun 22, 2006.

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  1. I've got the wild idea to make my own super nintendo game with a custom
    programed eeprom.. The problem is that they used a 40 pin surface mount prom
    which I believe is a SOIC package. Does anywhere stock a socket for this
    type of chip? I've found what appears to be the correct socket on an old
    cirrus logic video card, but removing it looks to be a real challenge. Now I
    think about installing a new one wouldn't be the easiest job either.. Any

    - Mike
  2. g. beat

    g. beat Guest

    You are seeing fewer sockets in surface mount designs.
    are you sure this 40-pin is a SOIC ??

    Assmann and Mill-Max make surface mount PLCC sockets.
    DigiKey parts catalog -- page 333

    For surface mount, you need to know the proper techniques in order to not
    routine the board or components. Good soldering iron and proper sized tip,
    temperature control, steady hand and some practice helps.

    I would highly recommend practicing on junked audio/TV circuits or computer
    motherboards for practice - (better in your parts drawer or junk box than
    the local city landfill)
    you might get a few expensive parts for free that way !!

    Surface mounting multi-pin components can be performed by hand --
    but other approaches are possible and work well.

    Seattle Robotics - Encoder (June 2000)
    Have you seen my new soldering Iron?
    Kenneth Maxon
  3. You are seeing fewer sockets in surface mount designs.
    Well I'm realtively sure that the old video card that I have has a SOIC
    socket on it but the prom in the SNES game I'm trying to put in a socket may
    be a TSOP instead. I don't know for sure yet becasue I don't have the game
    cartridge yet. I do however have a picture from a web site.

    The IC labeled U1 / mask rom is the one I need to replace with some kind of
    removable eprom, eeprom or anything else that would work.. (Flash Rom same
    as eeprom?)

    I have thought about making this simple and just solder wires from the board
    to a DIP socket.

    - Mike
  4. Memblers

    Memblers Guest

    That sounds like the way to go. IDC (ribbon) cable has the same pitch
    as the SMT ROM's pins, so a lot of people use that. Like here for

    I think the largest FlashROMs you can get in DIP-32 are 512kB.
    29C040, 29F040 etc.

    I would say to get a Game Doctor SF7 with a parallel port cable, but I
    see you're wanting to use a board with the FX chip. I don't think
    it'd work with that one (I'm assuming the FX chip reads from the ROM,
    but I don't know, really).
  5. g. beat

    g. beat Guest

    Try this web page

    The easiest but most expensive way to use SMD devices is to use a socket.

    See these 3 manufacturers

    Adapters and PC boards
    You can make your own PCB adapters (for breadboarding or whatever) with
    masks from a laser printer.

    If you want to use 100 pin IC with 0.5 mm pitch, you will need SMD pads 0.3
    mm wide and an isolation gap of 0.2 mm or 8 mil = 0.008 inch. One dot of a
    300 dpi printer is 3.333 mil ; 0.00333 inch or 0.08467 mm. The 0.2 mm
    isolation gap or track width are only 2.36 dots of a 300 dpi printer and
    only 4.72 dots of a 600 dpi printer.

    The precision of a laser printer is to bad too. Try to print a line of 100
    mm length in both directions and measure it with a high precision ruler. You
    will see errors of about 0.5 mm and these errors are different for both
    directions. Using InkJet's for photo-resist is generally a better idea than
    laser printers - the ink on a transparency is a little more opaque than
    toner on a transparency generally. Some of the newer Epson Stylus inkjets
    are at 1440dpi, which results in higher accuracy tracks at smaller pitch

    There is a free calculator at (it
    does require registration, but the allow you to log in thereafter with only
    your email address).

    There are pull-down menus to select the package you will be using, which may
    be specified three different ways. It then will give you a web page with
    complete specifications for the placement and dimensions for the SMT pads as
    well as exactly how the device leads will be soldered to the pads: Minimum
    toe & heel and side fillets are given. This is nice because the part vendors
    usually just give you the package dimensions and leave it as an exercise for
    the customer to figure out how big to make the pads.
  6. JW

    JW Guest

    My first stop is always for socket adapters.
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