This is the first time I've tried building anything like this, so I've been working my way through the build instructions slowly and step by step, all tests to this point have passed.
The tube holders were built and the LEDs are all working fine, I have soldered the tubes into the holders and plugged them into the main PCB. But...when powered on, all I get is the 6 LEDs cycling through the test, no activity on the tubes at all...help please!!!
Are you sure the tubes are good? Do you have any way of testing them? If you happen to have a "plasma ball" or similar gas discharge decoration you can touch the glass of a tube to the glass of the plasma ball. A good tube will exhibit some sort of patchy glow inside.
Are you sure all ICs are in their sockets in the correct orientation? The Atmega must be okay or the LEDs would not cycle, but what about the opto-isolators and the decoder/driver?
When you say all tests passed I'm assuming that includes the high voltage test, right? Check the HV test point again just to make sure you still have ~170VDC.
Look into it later when the dust is clearing off the crater.
Simply following the contruction guide. LV Circuit > HV Circuit, Tube Holder and LEDs > Mount tubes...everything is inserted correctly.
Page 21.. Once the six tube are mounted on their boards, and you have double checked the orientation of the boards, hook up the power, and check that the tubes cycle through their test routine.The digits “0” through “9” should be shown on each tube.