I've been building computers for some time now and have never experienced anything like this before. Basically, I had just put back together a very old Compaq P4 with 256Mb RAM system which I placed next to my PSU load tester, I was going to use this to control the load tester and attatch my USB osclillioscope to as the load tester requires a COM port and I don't want to trail the USB connector across the room to my main PC.
Anyway, I connect up the power and I noticed that the PC turned itself on instantly, strange, I thought, but I must have pressed the button as I was leaning over it to plug it in. So next I grab the keyboard connector, by this time I'd put the tower in position in a recessed part of my room which is raised off the floor. So I get up on a chair, rest one arm on the top of the tower, the other one on the metal load tester (the load tester was off, and the PC was on at the wall but switched off) and as I did I got a horrible electric shock which affected my arms. I know it was AC power rather than DC because my arm and forearm muscles contracted and I felt slightly stuck to what I was touching.
I'm convinced that it was caused by the PC as the load tester was off while the PC was turned on at the wall and there is clearly some issue as it turns on instantly when plugged in and isn't displaying any output. What I am assuming has happened is that the chassis of the PC was somehow live and (as I was standing on a fabric chair) the metal of the load tester acted as the grounding point and the current flowed from my right arm on the PC to my left arm which was resting on the load tester.
I'm slightly stunned as I have never experienced anything like this before and am confused as to how a PC chassis could be live with AC voltage. Not quite sure what to do now, obviously I need to take another look at the PC, but what could possibly cause AC voltage to end up on the chassis? Any advice would be greatly appreciated!
Anyway, I connect up the power and I noticed that the PC turned itself on instantly, strange, I thought, but I must have pressed the button as I was leaning over it to plug it in. So next I grab the keyboard connector, by this time I'd put the tower in position in a recessed part of my room which is raised off the floor. So I get up on a chair, rest one arm on the top of the tower, the other one on the metal load tester (the load tester was off, and the PC was on at the wall but switched off) and as I did I got a horrible electric shock which affected my arms. I know it was AC power rather than DC because my arm and forearm muscles contracted and I felt slightly stuck to what I was touching.
I'm convinced that it was caused by the PC as the load tester was off while the PC was turned on at the wall and there is clearly some issue as it turns on instantly when plugged in and isn't displaying any output. What I am assuming has happened is that the chassis of the PC was somehow live and (as I was standing on a fabric chair) the metal of the load tester acted as the grounding point and the current flowed from my right arm on the PC to my left arm which was resting on the load tester.
I'm slightly stunned as I have never experienced anything like this before and am confused as to how a PC chassis could be live with AC voltage. Not quite sure what to do now, obviously I need to take another look at the PC, but what could possibly cause AC voltage to end up on the chassis? Any advice would be greatly appreciated!
