Finally the boards are rinsed again with hot water, dried off with compressed air, and left to air dry overnight.

Next stop is QA testing!

#Tandy3-in-1

The second step of the cleaning process is to rinse the alcohol and flux off the board with hot water, again gently scrubbing with the toothbrush. Finally, the boards are scrubbed again, but this time with Simple Green. This stuff is great for getting the sticky residue off.
#Tandy3-in-1

Cleaning the boards after assembly and initial testing is wild. The process I've landed on is two steps
First, remove all of the socketed components and soak the boards in IPA for about 30 minutes. This softens the flux residue, which can then be scrubbed off with a toothbrush.
#Tandy3-in-1

Repeat the process three more times, and the install is complete.

I think these things are great. Professional looking, flush mount, easy to install, and mechanically secure for light duty use. And if you integrated them into a board design, can be a ground plane bonding point.

#Tandy3-in-1

Installing the rivnuts involves first drilling out the PCB holes by 1mm because I keep forgetting to change the schematics before I get the boards made. Once that's done, installation is simple. Thread the rivnut into the installation tool, insert into the PCB, and squeeze the handle.
#Tandy3-in-1

Starting to install the rivnuts into the backplates.
#Tandy3-in-1

And here are a set of completed mezzanine boards. The big IC is a TL16C552 which provides the parallel and serial circuits. The two DIP ICs are RS232 transceivers that wire between the 16552 and the DB9 connectors. Parallel hooks to the header connector, and the crystal clocks it all.

#Tandy3-in-1

And here are the main boards with a bunch of the ICs installed.

#Tandy3-in-1

Started another batch of the Tandy 3-in-1 V2 boards. It's always fun to see the progression from bare boards to finished PCB.

These are the base boards that hold the memory, ROM, and XTIDE components. The mezzanine boards contain the I/O circuits.

#Tandy3-in-1

Creating the FreeDOS CF cards is interesting. The card is tested and it's contents written on a Windows laptop, but the boot sector is written on the Tandy 1000 itself. I boot FreeDOS over the XTIDE serial floppy interface, and then write out the MBR with fdisk.

#Tandy3-in-1

Printing the Tandy 3-in-1 manual is always satisfying. I have to use this special super long stapler to bind the pages into the booklet. The red (naturally) tape helps align the staple at the correct spot.

Finally the adapter is given it's four mounting screws and is secured in the antistatic bag. Next up is packaging!

Every v2 3-in-1 adapter ships with its own CF card. This card is used in final testing to ensure compatibility. They're loaded with FreeDOS so owners can check if everything is working correctly.

Next is reassembly. Everything is put back together, and given a serial number. If it all passes the final testing, it gets the QA sticker.

Next on this V2 board's journey is cleaning.

I've tried all kinds of ways to clean PCBs after assembly, but the best I've found is a 15 minute soak in 70% IPA with some light toothbrush scrubbing, then another scrub with Simple Green, and then a hot water rinse. Sparkling clean and no flux residue!

This Tandy 1000 EX/HX 3-in-1 v2 upgrade board passed the first round of QA burn in testing, and is now prepped for cleaning.