Single-Board Universal Module

I got my boards yesterday (odd that I never got a shipping notice from batchpcb, they are usually good at that). I've got all the components, and I'm just waiting on the stencils which I only ordered on Sunday because I wasn't expecting the boards yet.
I finished building my reflow oven but I haven't calibrated it yet. Of course I have nearly no idea what I'm doing, so we'll see how assembly goes. Every time I look at the board and how tiny thepads are, I question my sanity.

Board in my PCBGRIP jig (I love this jig):


My oven with a ControLeo controller:

mikemacwillie wrote: That jig looks much nicer than the Panavise I use... Might have to look at buying one of those.

I had always planned to get a panavise, but then I saw the PCBGRIP. It is really well designed, is very stable, and has lots of attachments that make it easy to hold parts in place for soldering. It is not cheap, but I am so glad I bought it.

I'm still not sure what to do with the bottom of the board. I bought a stencil for it, but my guess is I'll try soldering it by hand. The other option I may explore is using low-temp Bismuth solder (ChipQuik) for the bottom of the board, and reflowing the top 1st using normal leaded solder, then reflowing the bottom at low temperature. The bismuth solders melt at 138C which would likely be fine for everything except maybe the LDO (which is easy to hand-solder).

the potential issue with hand-soldering is the crystals. I'm not sure you can get at the pads with an iron. we'll see.

victzh wrote: You have an oven, not a hot plate. You actually can just place crystals on the regular soldering paste and they indeed will be kept in place by surface tension. The only extra in this case - the board should be exposed to the heat on both sides, so it should be kept at the corners or by the mounting holes.

Not having done this before, do you do the bottom of the board 1st then? There are only a few elements on the bottom of the board, and they are all either very small or have large solder surface area, so I guess the surface tension should be fine. I would be much more worried about all the qfn parts being upside-down in the oven. If they move, it'll be a mess.

I got my stencils, and placed and reflowed the bottom of the board. Everything seems to have gone well, and got a bit of a feel for what it'll take to do the top. Spent most of the day moving components from the tape to little smd boxes and labeling everything. I have a vacuum to extract pieces from the tape, but I'm not happy with the control on the small pieces, so I guess it'll be tweezers all the way.

Anyhow, I've now got everything setup to place the main board. I'll likely wait until tomorrow though and give my shoulders a break.

Well, 2 hours of nerve-racking placement, and a very sore neck, and I got the board placed and reflowed. I haven't done a detailed inspection yet, but at 1st glance, it actually looks like it worked really well despite my pushing components all over the place to get things aligned. I only lost 2 components due to tweezer launch, so I'm pretty happy with that. I did find that my stencil is missing a cutout for paste on the rfx2401c and skyworks chip. I didn't have a syringe handy, but was able to scrape a bit of paste onto the pads. Anyhow, I won't be able to actually examine the board until tomorrow, but I think this was pretty good work for today.

Major setback. The board has a power-ground short. I checked it caefully, and haven't found it yet. I tested the un-populated boards and one of the other 2 also has a power-ground short. I'll carefully look it over and see if I can locate it visually. I thought I had checked the board before I assembled it, but I now think I only verified the 5V supply.