humming from soundcard and elictic "shock" from case help!

[ringer]

Hi all,

First post here, I will try to describe problem as best as I can.

Just recently built the following pc:

PIV 3.0 Canterwood
Intel D875PBZ mobo
1GB PC 3200 Corsair XMS LL
ATI Radeon 9800 PRO
160 GB HDD (Maxtor)
Samsung DVD/RW Combo
SB Audigy 2 Soundcard
Antec 480W PS
Chieftec case

Here is the problem:

I have been hearing a "humm" with my headphones on since I built this pc. I at first thought it was the soundcard, so I switched the card back to my old Turtle Beach Santa Cruz card and still had the humm. I did notice however, when I was unhooking the monitor cable from the back of the case, my forearm brushed the back of the case and I got a little "shock". Not a static shock that zapped me and was gone, but a continuous electical pulse on my arm. I can not remember if the computer was switched off at that time.

Today, I noticed if I touch the case with my hand, the humming goes away completely. This sounds like a grounding problem to me. What can I do?? Help!


Thanks in advance-Mike

[tmx468]

Is that plugging into the soundcard directly, or through the front of the case using a 'pass-through'?

That's pretty bizarre. Did you build the entire thing yourself, or order it pre-built? Maybe the board is grounding to the case through a stray stand-off on the tray or something like that.

[amdkt7]

Sounds like you are missing the ground connection to the PSU, perhaps you are plugging into an ungrounded outlet?

It would be a good idea to get a outlet tester ($5-10) from Home Depot that checks the plug wiring.

Also, all of your computer compents should operate off the same ac outlet.

[ringer]

I built the entire pc myself (first time).

The mic is plugged directly plugged into the sound card.

The computerr is plugged into a power strip with grounds, but the strip is plugged into a wall socket without a ground via an adapter (old house).

The ground connection to the PS?? Is there a separate ground wire for the PS??

[amdkt7]

No, no seperate ground wire. Sounds like your wall outlet is the problem. Today's computers really need to be properly grounded. Is there any other outlets that you can use? If not perhaps you can run a ground wire from the same point that the building uses for ground. Is this a house?

[Bill in SD, CA]

Originally posted by ringer
The computerr is plugged into a power strip with grounds, but the strip is plugged into a wall socket without a ground via an adapter (old house).

Hence your problem I suspect.

The adapter should have a wire to hook to a ground.

If not, run a ground wire from the case to a ground.

Bill

Welcome to TechIMO BTW!

[scholar]

Older houses may not have a true ground at the sockets, so attaching the wire from the adapter will not help.

Probably the easiest solution would be to run a wire from the computer case to a water pipe. You can get suitable clamps at a Home Depot type store

Regards

[ringer]

Thanks for the replies guys, I got the problem solved. My bedroom, added after the initial construction of the house around 1930, had grouned outlets. I just ran the cord to an outlet in the bedroom, and the humming went away!

Thanks,
Mike

[Uncle Bob]

I had a similar thing happen. I never got shocked. But since my house is early 1950's, I checked the set up with a multi-meter. My
Belkin UPS devise was showing a red light, improper ground. My wall outlets are the two prong polerized type. I sandpapered the
screw that went through the three prong adaptor,into the metal
box that holds the outlet. After cleaning the conections, all is well.
It seams that all of the outlets in the house are in the metal boxes and the boxes are all grounded to the cast iron plumbing.
That's my $0.02.