> OK, I am going to do you suggests... thanks by help.
Please don't if you want to live. If the HV connector wasn't seated properly, either the screen would not light up at all, or you'd get visible arcing, a loud snapping/sizzling/hissing, and an ozone smell.
Either your speakers are interfering with the monitor (remove them temporarily to see) or your CRT has a manufacturing defect. It's not the HV connector and it's definitely not the yoke.