I Just got done building a classic Rev4. I am experiencing problems after initial start up.
I am using a 12v power supply and have a RTC for the time keeper. The first time I powered up my clock all the tubes couted from 0 through 9 as expected. I pressed the button when all the tubes read 8 per the instructions. After the button press the tubes did some counting and stopped at 01 74 00. After a few seconds the display went back to all 8 and then went blank.
I have factory reset it several times and yield the same results. Button presses do not do anything when it is blank.
Please disconnect the RTC for a moment and test again. I have seen something like this in the past when there is an error on the I2C bus.
One of the last things that happens when exiting test mode is that the RTC is asked what the time is. I don't remember exactly what the error on the bus was, perhaps it will come back to me. It was quite a long time ago.
I'm not personally familiar with this particular problem, but I'd say try what's easiest first. I suppose that would be to pull the battery. Power up with the battery removed, see what it does. If it works, power down, re-install battery, power back up and see if it's still working right.
If battery pulling does not solve it then proceed with more drastic measures (remove RTC completely - power uo with RTC disconnected).
That's the best I can do, and Ian is probably asleep now seeing as it's 01:00 where he is.
Look into it later when the dust is clearing off the crater.