PC Problems

I agree to some point. I have several PC here supplied by the OEM as I/O devices to the PLC running my equipment. I have had some problems with them. But I believe no more then any which were used at home considering the amount of use they get. They are contained in an enclosure which does have a fan for ventilation.

Its difficult as we do not know what the environment is like from his statement. I would say its time to replace it. Computers are inexpensive. I also suspected that maybe continuously unplugging and plugging in the board may have damage the socket continuing the problem. Who knows the problem may not be the connection in the socket at all. Could be a solder joint on the board itself. The stress of pulling it in and out is correcting for a short time.

I am guessing (meaning that it's an educated guess rather than specific experience) that your fruit packing store is refrigerated and has high humidity. (Fruit storage conditions to minimise deterioration.)

In that environment there is likely to be significant opportunity for condensation inside the computer if it is vented from that environment. Fruit stores seem to be at a humidity level where there is condensation on most surfaces and your PC boards would be no different.

The other possibilities relate to the location you described. Vibration from the machine could be causing the boards to move in the slots and those micro-movements could be doing all sorts of things to digital signal.

Finally, what is the usual cleaning regime in the store and for that machine? Are there hoses waving around with high velocity water, or even compressed air blowing water off surfaces after cleaning, or buckets of hot soapy water.

Have fun!

Humidity is extremely low in refrigerated storage areas.

Another possible fix would be to use dielectric compound on the contacts. The trick is to find one that is compatible with circuit boards. Any suggestions on a brand from the crowd?

If the real problem is boards coming out of their sockets, I would try putting plastic 'scrubbies' (like the 'chore boy' scrubbies, but plastic) over the boards and have the cover apply pressure to hold the board in place. The scrubbie will not interfere with ventilation too much, I hope.

All the advise about using a PLC or industrial PC are 100%. But if you can't do that right not and it is just a corrosion issue on the cards. Clean them with a eraser and put a THIN coating of vaseline. This is the poor man fix but it will slow the corrosion. Up grading to a PLC or industrial PC best option.

We have a problem of clay giving off sulphur as it dries. This corrodes our motherboards quite quickly.

Now out IT dept. sprays all new computers motherboards with hair spray prior to installation. This lacquer prevents the corrosion problem.

O M G .....

You know that stuff is flammable right?

If what is described is the only problem with the computer. Make liberal use of CorrosionX

http://www.google.com/search?hl=en&source=hp&q=corrosionx+electronics&aq=8&aqi=g10&aql=&oq=corrosionx&gs_rfai=CFYSbiWQrTPiuBpaWMfmhxPkJAAAAqgQFT9Cs9WE

And physicaly restrain the board.

Certain atmospheric contaminants can accelerate the oxidation of edge contacts and microchip terminal connectors. The oxide layer is highly resistive, and can disrupt the operation of the card. One common method for correcting this oxidation is to re-seat or "rock" the card in its socket, which scratches through the oxide layer to allow a good metal-to-metal contact.

Most ripening fruit emits ethylene gas, C₂H₄. I suspect the gas is causing your problem by creating an oxide layer on the contact points. The problem can be prevented by moving the PC to a location away from the fruit, or to enclose the PC in a sealed enclosure as suggested by JRaef.