Pads tearing off of PCBs

in PCBs by DP | 19 comments

Voidptr got a board from eBay that may have used an exceptionally cheap PCB. He soldered some pinheaders to the board and with slight pressure the pins flew of the board:

I just got this ebay board and got a bad surprise, I soldered the header, did not overheat it I’m pretty sure. Connected few wires and plug them on a breadboard …  While moving the breadboard around all pads of the ebay board broke off …

What kind of hacking hazards do you encounter?

Via the forum.

This entry was posted in PCBs and tagged , .

Comments

  1. Vladimir says:

    Bun pinheaders must be mounted through-hole.

  2. dieter says:

    obviously smallsize SMD pads are not meant to mount details, which might have pressure or heavy weight conditions.
    additionaly should be used some termical clue or silicone to secure this kind of connections. put the clue to as large area of board as possible and as much as possible and maybe thats your lucky day :)
    or use whatever additional mechanical abilities to avoid this flew away…

  3. Ethan says:

    SMD pads are never great to solder to. I usually put a bit of hot glue or epoxy around the solder connections if I absolutely must place TH pin headers.

  4. Niklas says:

    I am surprised, or maybe not, that they used SMD pads instead of through hole pads just for this connector. The other visible pin headers are all through hole mounted.
    The overall feeling I get from the picture is that the board layout has more design flaws, just to mention some of them:
    - Capacitor placement
    - Copper pour broken up
    - Silkscreen over component pads (MISO)
    - No via teardrops

    • voidptr says:

      yes SPI bus should have through hole mount anyways …
      no see on picture, power is also on big flimsy pads …
      jtag is on pads, (that is ok i guess … )

  5. Destate9 says:

    Bummer, I’ve had a couple pads lift on me, but not due to THT on them, just heat. Xbox motherboard traces and pads are not meant to be soldered with a broken soldering iron stuck at max heat… Also, who uses pads for a SPI bus anyway? I’d be pretty salty if I got that board and saw that there were just pads for the SPI bus.

    • voidptr says:

      i got one perfboard like that last summer,half the tracks and round pads were not sticking on the board itself a little bit of heat and they were pealing off.

      luckily i had only 1 or 2 resistors soldered on it, i just put it in the trash and start with another board, who worked like a charm !

      it is more frustation with this board, whou is more $$$ :-/

  6. Flavor says:

    I guess that’s what right-angle headers are for.

    Though, I have seen this technique work for double-row headers with one row on each side of the PCB.

  7. I once had problems with a 0.1″ pin header connector – the sockets inside the female connector made extremely poor contact. It was for an LCD display and only about half of the pins were connected! Swapped it for a different style of connector and it worked fine. Some pics –

    http://imajeenyus.com/electronics/20111205_faulty_pin_header/index.shtml

  8. rsdio says:

    Those solder blobs look HUGE! I don’t think they look right. The solder should be concave in outline, not convex. I suspect the soldering technique may have contributed to the problem.

    • voidptr says:

      i just put the header for some quick breadboard tests, it would has been removed in the end project .

      yes solder blobs are big i didn’t had small leadtin handy so there’s solder completely around the header pins. make the blobs look huge …
      no a problem for my tests …

      • rsdio says:

        That large iron might have been the problem. I always use a small soldering iron for SMD work. The larger ones have much higher wattage.

  9. philip says:

    I experienced this a lot – overexposing the pads to heat might have caused the problem. cheap PCBs from ebay, seeed manufactured PCBs and even home brew etching is not safe from excessive heat.

  10. Jaxxco says:

    Use pogo pins for programming!

  11. Drone says:

    I can’t believe this post is getting as much air time as it is. From what I can glean, the board came from the ebaY seller with NO header on the pads. Then the original poster soldered a header on the single-side pads and was “amazed” that it tore the pads off the board. What the heck did he expect? Never-mind if the design is poor (no through-hole pads). I would NEVER solder a header on single-side pads like this in the first-place.

    • Yep, have to agree there! SMD pads do not have much strength. Even through-hole pads on a single-sided PCB can sometimes be dodgy. If it’s a programming connector, either use a staggered through-hole pin header (so friction holds the pin header in while programming), or use spring pins. Or an edge connector (I’ve used hacked-up bits of old ISA connectors a lot for edge connectors)

  12. Dolabra says:

    I do this pretty frequently with homemade boards because I hate drilling holes. I’m yet to pull pads off. 1/2 the time I will solder a temporary programming header on with wires between the pads and the pin header. I do this because it is a lot easier to de-solder 5 wires than it is to de-solder a pin header.

    thanks for sharing voidptr.

  13. ewertz says:

    I don’t know what the problem is… those pads lifted perfectly cleanly! You know you’ve done it wrong when the trace it connects to dangles off like a hangnail.

    I say “well done”!

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