Power supply negative and a vga connection creating a short - Page 1
Forum section: electronics / beginners

author: alaradia
author_rank: Newbie
timestamp: March 16, 2015, 02:17:37 pm
content: i was testing to see if this monitor was working and i didn't have the original power supply so i found a connector head for it hooked it up to my power supply and turned on the power supply it blew the fuse on the power supply so something must of shorted i grabbed a replacement fuse and tried again this time the power supply was still on and i touched the negative to the power supply and a crap ton of sparks shot out(Positive was not connected) i double checked that i was imagining things but sparks happened when i tried again so i did 2 things i disconnected the vga and plugged my power supply into a different power bar then my computer is attached to so i tried again and no sparks and the monitor powered on but since i did 2 things i didn't know which worked so i put back the vga cable back in and sparks flew from the negative on my power supply again(when this happens the voltmeter built into my power supply maxes out) since i had the vga connected to a kvm switch and then to my computer i figured it was best to see if removing the kvm would fix it and hook it directly into my computer that got rid of the sparking/short on the negative but when i hooked in the positive after i put in the negative it blew the fuse i am guessing i'm some how shorting via ground maybe i'm not 100 percent sure but the same type of issue was happening between my serial to usb and my power supply before when hooked to a serial lcd so any suggestions on how to stop this occurrence and a explanation of it would be very helpfulPower supplyHP, Hewlett Packard 6284Ahttp://cp.literature.agilent.com/litweb/pdf/06284-90002.pdfmonitoryamada l-171kvmiogear gcs42uw6http://www.iogear.com/product/GCS42UW6/

author: amyk
author_rank: Super Contributor
timestamp: March 16, 2015, 03:03:01 pm
content: You may have defective mains wiring, be careful as you could create a dangerous situation. Check the voltage between the two grounds. If it is roughly mains voltage... it'd probably be better to ask an electrician about your mains.

author: alaradia
author_rank: Newbie
timestamp: March 16, 2015, 03:13:26 pm
content: Quote from: alaradia on March 16, 2015, 03:13:08 pmi tested between negative on my power supply and ground on mains and i was getting 38 volts not sure if thats enough to explain the sparks and the fuse blows(i could be very wrong about that)

author: wraper
author_rank: Unknown
timestamp: March 16, 2015, 03:17:35 pm
content: Probably positive output is connected to GND or something else on the back connections.

author: alaradia
author_rank: Newbie
timestamp: March 16, 2015, 03:24:51 pm
content: Quote from: wraper on March 16, 2015, 03:17:35 pmon minea3 a4 and a5 are connecteda6 a7 and a8 are connecteda9 -s and - are connected+ +s and a10 are connectedPicture of back attachedit looks like ground is supposed to be attached to + +s and a10 though since i don't understand the back of the power supply nor did i know it existed i wont try it till some one can confirm my suspicion or give a different idea on how to fix iti tryed it simply maxs the voltmeter built into it

author: alaradia
author_rank: Newbie
timestamp: March 16, 2015, 05:21:01 pm
content: well i just hooked up a wall wart so the monitors running fine now so its not urgent or anything but it would be handy if any one could make suggestions to fix this issue since its already blown up a few of my projects