For assembling instructions,please check:
https://vfdclock.jimdo.com/2017/08/01/thermometer/
We add an extra IV-19 NIXIE tube to display [+]&[_]&[~],based on the 3-Tube NIXIE Thermometer design,others are all the same except the source code.
Please use Acrobat Reader from ADOBE to open the PDF in the page,or you may not be able to get the attached files inside the PDF if using other PDF reader!!!
Add-ons:
1mm grid of topside of PCB