Mark II Update - August 2020

Originally published at:

We received our first set of prototypes of the SJ201 board this week. As predicted there was some good news and some bad news.

Let’s get the bad news out of the way first. Unfortunately part of the shipment was lost coming from China to California. In order to expedite the prototypes we had the manufacturer make a set with the top half of the board assembled and a set with the bottom half of the board assembled. The idea was to sandwich the two boards together to create a fully working unit. Unfortunately one set was lost, and we weren’t able to create a complete working prototype.

Bottom of the SJ201 board with hand soldered components


The good news is that Kevin was still able to test a lot of the systems from the half that did arrive, and identify some changes that need to be made. Additionally he was able to populate the other half of the boards by hand for an almost working prototype.

Testing out the SJ201

The power (5v and 12v), USB sound card, amplifier, buttons, and LEDs all tested successfully. The major untested system is the XMOS XVF3510 and microphones which create the audio front end. Even if Kevin were to successfully hand solder the XMOS chip there was an issue with the thermal and ground pad. A 1v pin interfered with the pad as it extended out further than anticipated. A keep out is necessary to fix the issue. There are many other smaller issues that have been addressed too, and we are nearly ready for the second spin of boards.

Up close and personal with a 90mm macro lens

These types of issues were anticipated and we would have felt very lucky to have had a completely working prototype on our first spin. For the next batch we will use a board house that can fully assemble both sides of the board.

Stay tuned for more updates on the progress of the SJ201 boards, and jump into the ~Mark2 channel on Mycroft Chat if you want to see all the granular detail as testing continues.

1 Like