I just finished building the ice tube clock kit following the instructions here
Voltage test 1 passes - input to the 7805 is 9V and the output is at 4.9V.
Voltage test 2 passes - 56 volts at D3 (striped end) without IC2 (VFD driver) plugged in and 14.2 volts with the driver in the socket. (VFD not plugged in at this point)
After completing the main board, without the VFD board plugged in, voltages at the source and drain of Q4 is about 4.7 volts. I believe this is correct as well.
However, with the VFD board plugged in, I get no display, and the following are observed:
(a) Voltage at D3 now falls to about 8 volts
(b) Voltage at Q4 Drain terminal falls to about 2.7 volts
I observed that there is no resistance between VBIAS and GND pins of the VFD (continuity test with my multimeter beeps). This seems strange. Is the VFD shot? A few pictures are in the album below. Any tips appreciated.https://picasaweb.google.com/101913593427540595709/IceTubeClockTroubleshooting?authkey=Gv1sRgCNDo9_Cv25G3Jw