Communication problem between two PCs

Has anything electrical or electronic changed near your PCs or the cable which could be generating electrical noise (such as a new arc welder or any machine with brush motors)?

Hello Signode:

You didn't say how you tested the cards so I'm a little in the dark here. To me it sounds like component failure on one of the cards or motherboards. I'm basing this on your information that seems to indicate that the problem is heat related.

In the past I have diagnosed this type of problem by cooling the suspected device with a little refrigerant, I believe they also specifically marketed a product for electronics to do this. My suggestion would be once failure occurs, I would leave the machines running and cool the communications cards, if you regain function you've obviously found the problem.

Ethernet cards are cheap, if you have a few friends with computers they may well have some lying around, (I think I have a half a dozen or so lying around from machines from the past) so you could replace both cards with some 10 100 ethernet cards without incurring dramatic expense and skip the testing, plus upgrade your system at the same time.

I would update the drivers for the network cards on both PCs or like suggested, put new ethernet or coaxial network cards in both machines. The connecting cords for ethernet are easy to trouble shoot or replace. Coaxial cable has a 75 Ohm resistance that depends on quality connectors that are not worn from moisture or dirt and time. The connectors need to be replaced from time to time. The 75 Ohm also has to be supported by the terminals on both ends which would be your network cards. The grounding of both PC chassis is important for the terminal to accurately produce a 75 Ohm resistance. There is also the factor of the coax having a tight radius bend somewhere along the cable or some flattening or just plain damage from an unnoticed event. Passing power like in cable tv is more forgiving with defects in the cable but, in the case of network cards and lower power transmissions, i would seek perfection in the health of the actual coaxial cable and it's end connectors.

Check to see if you have any buffers filling up and slowing the machines. Defrag the PC's. If you are storing information for reports, try clearing them after printouts. When was the last time the PC's were cleaned both physically and with software?

Dear Friends,

Thanks for replying. I have been working on the points mentioned you all and will be reporting back to the forum soon.