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There are several cases in which you are anable to complete, even start, the power-up process along with x-ray shutting off, anode stopping rotating, and even a total power down. In the particular example shown on the left, you've powered the system up to 50kV 94mA - almost there (Fig 1.), but it was interrupted, when you tried to increase the current further, with the TC (tube current) alarm lamp lit and alarm on (Fig. 2). Below is a table of the meaning of a lit alarm lamp, a number of them being related to power-up failure.

CM: Abnormal chill water flow.
LW: Water leaks, mostly in the target.
HV: Voltage to tube above upper limit.
LV: Voltage to tube below lower limit.
TC: Current through tube above upper limit.
FC: Filament burned or with abnormal through current.
OL: Power to tube above preset level.
LC: Unduly large current from power source.
VC: Tube vacuum greater than 0.01 Pa.
TR: Target rotation speed too slow.

Among these causes, HV, TC, FC, OL and VC can happen in power-up process. All these symptoms have a lot to do with the pace of powering up and the vacuum status. For any of these, do the following.

1. Try power-up again with a much slower pace and watch IG (vacuum) reading more closely.

2. If above failed, the most likely cause is bad vacuum. Get rid of that problem and try again.

3. If failed again, open up x-ray tube and check the connection of the filament terminals. Make sure the two lead wires are straight down and parrallel to each other with the largest possible distances from one another and from the walls of its housing. Meanwhile, check the surface of the target drum and polish the anode if necessary.

4. A rare case but could happen - the vacuum gauge, a lit-on glass tube underneath a metal cover in the back of the tube tower is burned. Check if that's the case (try to spot bad outside connections, cracks on the glass tube, burned filament inside, etc.). If so, change the gauge.

5. Even rarer but happened before - the oil level in the high voltage tank underneath the base of the machine and in the back is too low. Switch off the house main power, unplug the black-and-thick cable to the tank, dip the black stick (wipe clean it first) lying on the tank into the tank. If the oil level is below the lower mark on the stick, add more oil (in a white small plastic bottle).

6. VC alarm-on results a complete shut down of the whole system, even the power. This is caused usually by unusual degassing from the filament or the target drum when heated up (they may be too dirty). In this case, you have to restart pumping the vacuum after eliminating other problems that may lead to a bad vacuum.