Power? Too much Power!!!
As an ex-field engineer I have lots of stories to tell about customers 8alls ups or mistakes or unreliability between the brain and fingers or telephone.
One day I get a call from a very high-tech engineering business.
"Hello It Support" I answer.
"Ah, hello. can you help us?" the caller (male) says, "The monitor of my PC is all wobbly."
"Wobbly??" I ask
"Yes, Wobbly, like a jelly." the caller explains, "You know like a jelly. It's the picture, its all wobbly. can you help?"
"Of course I can help, what's your address?" I ask.
I got the address and headed for the van. I took my toolkit and I wondered what "Wobbly" actually meant.
I arrived onsite after a short 15minute drive. I passed through security and was left in the reception of the office, cum factory.
A few minutes after the receptionist called a number a rather harassed man in a suit rushed into the reception.
"Hello, are you here for the monitor?" I was asked.
"Good, follow me." I was told.
We walked through the office building and up a small 4-step set of stairs, along another corridor and into a windowless office.
"Look" I was told.
And lo-and-behold, I saw a monitor with a wobbly screen. It was an old-style CRT plugged into a minitower on a desk. There were another 3 similar PC in the office, the others were okay.
"Have you swapped the monitor?" I asked.
I unplugged a monitor which was working on another PC and plugged it into the PC with the wobbly monitor. This monitor appeared okay but after about 20 seconds it started to wobble like the original. I plugged the wobbly monitor into the PC with no monitor and the picture was perfect - no wobble.
I went to the van an picked up the loan monitor and video adapter I always carried with me, plugged it in to the faulty PC - there was a significant wobble on the screen. I powered off the PC and rplaced the VGA card, powered on and waited...
I swapped the VGA card back to the original and moved the PC to another desk. The display was perfect. No wobble. I moved a working PC to the desk where the faulty one was and it wobbled.
So, a faulty PC and monitor moved from one location to another and the fault didn't.
I stood for a few seconds. Another engineer from the client company entered the office, I looked at the door and could see the beginnings of the factory. I left the office and looked along the wall. Through the partition wall was a 3-phase, 415v junction box.
Aah. The solution. Power, but not in the right place. I showed the engineer the solution - to move the PC or the junction box. The elected to move the PC and the issue was fixed.