Vesper finally reflowing! … but

vespfer

YAY!

Today was the day! I could finally get around to reflow one of my Vesper boards, and the first impression is pretty good, if I should say so.

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All components was reflowing just fine, and the amount of solder paste seems to be spot on too. But again, it should be so too when using a stencil for applying it.

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With the Impee running on the official April board, it is drawing about 45mA on my bench power supply, on my Vesper board with one green led on, and two pull-up resistors, it went up to about 70-78mA, so almost twice as much, but still it isn’t really that much, and since it is going to run on a constant power supply and not batteries, it does not really matter that much.

BUT!

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After putting it all together, I found a problem… the transistors could not drive the relays. So to figure out what was wrong I checked the datasheet, and got just as confused as when I made the layout the first time, then asked a friend to double check for me, and what did he find? I got so confused when I made the layout, so I had switched two pins around.

As you can see on the picture, just in front of the relays, the two transistors is now standing up, and then got a part of a leg from a through-hole resistor going down to the PCB again.

This error has now been fixed in the layout, and I will change some other small things, then order a new set of PCB’s. The ones I got does work just fine, but I also want them to be good enough so I can be happy about them.

4 comments

  • I’ve had similar confusion on pins. In my case, it turned out that I was reading the pinout from the wrong package type. So a different package, a different pin order. Thankfully it was just a breadboard circuit.

    • A bit more difficult to change on a pcb 😉 But I am already work on the next version, will change some small things to get a more stable 3v3 and the other things I mentioned in an earlier post. 🙂

      • Yeah. Some people modify the PCB to fix it (cut trace & jump wires), but it might not be as durable. It least would prove the design before getting new PCBs made.

        • I just made the transistors stand up on two pins, then run the last one back down to the pcb, works fine. 🙂 Next thing I need to do is more testing, and then order a new set of pcb’s.

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