hi there again!

I am repairing an old monitor (I was not able to get the serial). But
its oldy im sure. During power on, i feel a static at the front of the
monitor. An indication of a high voltage but after a few minutes, 4
minutes i think, it suddenly shutdown. So I used my multimeter and
tested the collector of HOT. I measured a voltage but when the monitor
dies up, the voltage also disappears. I changed some bulging
capacitors but still the problem persists.I suspect the deflection
yoke but I have no yoke tester. I heard that running a monitor without
deflection yoke disconnected is not good. I am a little bit lost here
because I havent practiced it for long time now. So can anybody give
me suggestions on how to fix this problem. I know safety precautions
in electronics. I want friendly advise please. Thanks in advance.