Ab Dh+

I have an assembly line I do a lot of modifications to, no one has put the termination resistors on it yet, (but will soon as they let me have the line, its a 24/7 operation), my question is, can going online with your pc and no termination resistors cause the motherboard in your pc to go bad. I have just had my 3rd one replaced. The slot for my pcm card becomes non functioning. I will be online with my pc, it will go offline and when I click retry my computer is frozen. At this point I have to power down and remove the card to get my pc to boot. I am just wondering if my pc is a lemon or if the lack of resistors can cause this?

I worked on many machines with missing DH+ end resistors and never had any serious problems. I had a failure like the one you describe that we nailed down to a floating ground on one particular machine.

That could be an issue, this machine has been modified, remodified, over and over again. It may only be affecting my pc, because I am low on the totem pole and get most of the jobs for that machine, so I am online with it more than anyone else. I did tighten and check all my connections and they all seemed ok, but I didn't check my grounding...yet.thanks Okie.

AB Com

DH+ and remote com cables require the terminators to reduce SWR. The absence or presence of the resistors will have no effect on the computer. There are issues of driver or hardware problems here. I use a Dell P3 600 and a Toshiba 486. Have had no problems. Make sure the slot is dead and not just "hanging" or locked up. Com errors can act like the interface is dead. If you dont get the red screen of com time-out then try plugging directly into the front of the PLC and see if it works OK. My advice is buy a new notebook... Bruce.