There is no real significant risk remaining. At this point the product is as good as we can make it in its current format. Realistically, there are many design improvements that could be made, however they would require redesigns of core structures which it is far too late to make. We are pleased with the functionality of the device as a whole, and satisfied with the outcome.
The major design change made this week was the topload. We tried a large one but it ended up being too large unfortunately. Ultimately, through testing, a number of different toploads (including the large one) actually do work, however, the 1.5 inch diameter is most successful overall.
There is not realistically an updated schedule to provide, the only thing happening next week will be a slight improvement to the cooling system.
All in all, the system technically works. It has some quirks sure but it does arc freely (though does produce significantly stronger arcs when a conductive surface is nearby) and can even manage tonal outputs. With this, as stated earlier, we believe the device is as good as it can be without significant redesign work.
Unit tests:
Initial interrupter testing: Exposed that the original interrupter design would not work, as duty cycles were far too high.
Redesigned interrupter testing: Revealed successful design.
Repeated gate driver and oscillator testing: Revealed need to ground unused schmitt trigger inputs. Revealed instability of bridged output operation of gate driver IC. Revealed effects of inductive ringing.
Redesigned gate driver testing: Revealed successful design.
Repeated independent coil resonant frequency testing: Though initially giving confusing results, eventually led to proper turn count on primary coil, and revealed need for differently sized toploads.
Intial arcing tests: Helped establish that coils would successfully function. Helped establish resonant frequency of combined coil system.
First integration test: Exposed need for unified ground.
Second integration test: Revealed need for coil redesigns. Also revealed mosfet limitations and heat management issues.
Final integration tests: Exposed flaws in design that were not previously detected. Many of which call for major redesign to fix, but do not stop device from ultimately working.