G120 soldering

Gus me old diamond - is there any chance of getting a bare or old G120 board to practice soldering in tight spaces?
I have the start of a design and i want to see if i am kidding myself about hand soldering etc before i start getting too giggly about how cool it will be.

I have found that everything with a pin pitch greater or equal to 0.5mm is doable by hand. Of course the pins must be accessible when the component is in place.

Tools I use:

  • Solder iron with 1mm or smaller tip
  • 0.5mm are smaller solder
  • No-clean flux pen
  • Solder wick to remove excess solder
  • Tweezers with sharp points

@ WouterH - Thanks Wouter, looking at my Cobra and using that as a guide i’m not to worried about the G120. What i am more worried about is getting in there with the other edge connectors, so i’m wondering if i have to change them to thru hole instead…

I suspect that if you solder the G120 first, then the DB9 and DB25 then you will be fine. Same on the other side…

For LQFP packages, I’d still use a nice wide tip. Just drag it across the pins, and it’s like magic. I’ve never tried to solder a G120-type package before. I’ve got a project upcoming here that uses some, so we’ll see how that works out :slight_smile:

You do not need to solder anything :slight_smile: Check back next week :wink:

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@ Gus - o yes i do :wink:
But still look forward to a nice Gadgeteer board…

@ Gus - Better add on a couple days after the week :stuck_out_tongue:

@ Michael - lol

This is a part of a board we did at work. The modem looks about the size of the G120. I assembled 2 compelete boards by hand, around 500 parts per board, and we had another 28 assembled via pick&place, but we didn’t trust them with the modems, so I had to solder those 28 modems by hand, after the rest of the board was populated.

The soldering was fine. The only problem I had was that both short sides of the modem was mostly connected to a big ground plane, which made it hard to get up to soldering temp. But space was never a problem.

And your part near the G120 are lower, so less intrusive.

Edit: Ahh, I see it isn’t DB25 & DB9 connectors, so they are even lower…

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This is a part of a board we did at work. [/quote]



Agreed - how long did it take solder each board?

Thanks guys.

For just the modem it took around 20 minutes to solder, first cleaning the pads of the solder that was stenciled on…

Placing the 500 parts took around 5 hours per board, then 5 minutes in the toaster oven to reflow it…

The 5 hours was after we had set up a video projector so that it projects a virtual copy of the board onto the board. Then the guy that designed the board could mark all the spots that take the same value part, then I can place all of them, then we moved on to the next part. Previously it was almost a game of Go Fish, I call out a part designation and he tells me what must be placed there, and if it isn’t the value that I have in hand then I try another part designation. That way took around 16 hours to do one board.

@ GMod(Errol) - Wow. So did you build 1 or 2 boards per day?

Luckily I only did two boards, with about a week between the two boards. We needed them for prototyping the mechanics while the pick&place people did our boards.(and I had to go through those boards as well to place parts they forgot/didn’t notice/bumped off/something).

Needless to say I was paste after every board…

@ GMod(Errol) - nice job!


What kind of oven do you use… anything special?

Just a normal desktop oven. I think they are sometimes called Toaster Ovens. Ours was around $50 new. We dont have temp control yet, so i put the pcb in, turn it on, and turn it off when i see that all the solder paste have melted…

Two things speed up our prototypes hugely. One is the oven, the other is using a solder paste stencel to quickly place the solder paste everywhere it should be on the board.

@ GMod(Errol) - Once the thermocouple module is ready, you can start controlling it with Gadgeteer.

A friend has built this one: http://www.elektor.nl/artikelen-als-pdf/2006/januari/smd-soldeeroven.53633.lynkx

It uses the MAX6675 Cold-Junction-Compensated K-Thermocouple-to-Digital Converter (0°C to +1024°C)

Yeah, Gadgeteer would be the simplest. We will be building a temperature controller for another project, using the same thermocouple chip and a PIC, and the plan was to just use one of those boards to control the oven. But I vote gadgeteer. :slight_smile: