Greetings, I'm obviously new to the forum here so greetings to everyone. I am here because I have a problem with some equipment relating to my job and I'm trying to learn as much as I can about it and the effect that it is having on our equipment. I'm not looking for a 'solution' so much as just trying to understand the implications of the situation. Here is the outline of my problem: We have a device that runs off of a 14vdc external PSU. This equipment has experienced various problems in the past and has come to my desk as something to investigate. Unfortunately, due to the nature of this equipment I can not go into as many details as I would normally prefer to do. The end result here is that when I place an o-scope probe on the chassis I clearly see a 150vac peak to peak voltage. It's not a perfect sine wave but it is close with the exception that part of the top of the wave is cut off. Now, I do have some experience working with with electronics, but I am by any means an expert. I do know that this is a 'double-insulated' power supply and the because of that the 14vdc is 'floating'. I also understand that the reason I see this 150vac wave form is due to the floating nature of the PSU. My question here is how normal is it to have such a large ac voltage like this? How possible is it that this is causing some of the strange behaviors we've been seeing? I had also found that if the ac power plug is not fully inserted then the PSU will output pure ac just as if it's coming directly from the wall outlet, though I don't actually know how much current is there. I hope I've stated my problem clearly enough, but if there is anything that I need to clarify, please just let me know. I sincerely hope that someone here can help me to understand the situation.