I have used Bridgeports for 30 years, and currently own a BOSS 5 Ser I and a BOSS 6 Ser II CNC. They have both been solid machines , but have also had their problems. Your problem sounds like a simple (??) one, DIRT. What has probably happened is dirt and oil (a potent combination that is electrically conductive) has gotten onto one or more of your boards and is causing the fault. Even if they seem clean, I highly suggest that you clean all and I mean all of the boards. Take off the covers (and check the air filters while you're at it) and check the boards. If you see dust and dirt on the filter, the boards are probably in need of cleaning. Follow these instructions and you don't need any harsh chemical sprays or environmentally dangerous chemicals. (The maintenance manual says to use a Freon-based cleanes, but what did they care about the environment in 1980?) Carefully remove ONE board. Be careful if the air is dry, or walking around on carpets, as static electricity can KILL these boards. Touch some grounded object before handlilng the boards, just to be safe. Start at the left hand side and remove the locking bars that hold all the boards in. The 1/4-turn screws are supposed to be captive, but may not be. There's a separate clamp in addition for the LSI board, which is the one on the left end. Remove it, too. The board may come out hard, so use two hands and DON'T get your hands wrapped around any of the fragile components on the board. If they're still there, most of the boards have metal or plastic ejector levers that will help in pulling them out. There are no connectors on the LSI board, so that's a good one to start with. Once you have it pulled all the way out, carry it carefully to a large wash sink. Run water at a comfortable temperature. Put some dishwashing detergent (DAWN is good) on the face of the board (component side). Use a nail and knuckle brush, or an old toothbrush to scrub the board. BE CAREFUL!!! DO NOT work the capacitors back and forth, they WILL break. Pay especial attention to the soldered IC's, as they are most likely where your problem lies. Soap and brush along both sides of each IC carefully (and watch out for those little capacitors at each end of most of them), rinse and check each one. LOOK for dirt bridging between the legs of the IC's. If necessary, and you MUST be careful, use a bit of ScotchBrite or a BRASS bristle brush to clean up the legs of the IC's. The worst areas will be at the bottom of the board, and the lower side of every IC, getting better as you go up the board, but clean them all. When you're satisfied you have the front clean, turn the board over and clean the back. There may be jumper wires there, so treat them gently. You'll probably notice a smear of oil and dust at the bottom of the board. That's the culprit.
DO NOT, REPEAT, DO NOT EVER USE AN AIR HOSE TO DRY THE BOARDS. Many reasons, just don't do it. Stand the board on edge and let it drain. After it's dry, take another look at all the IC's. You may have gotten the oil, but might have left a caked on layer of dirt.(It may show up as a gray-brown stain) If necessary, do it all over again. Once you have the first board draining and drying, go take out the second one. If there are connectors and wires, work them loose carefully. They should all come out and "hang" from the wiring harness in a clear order, so hooking them back up won't be confusing (Except one, which I will mention later). If there are plastic covers over any switches on the boards, or small plastic trimpots (about 1/4" square by 1" long, usually on the edge of the board) try to avoid getting them too wet. Avoid running water into the switches. Proceed as before to clean both sides of each board in turn, and stand it on edge to dry. SPECIAL NOTE: On the board labelled ERS, you will probably find one connector (K10) hanging loose, unless the machine is set up to operate from a Teletype. This is supposed to be off, to enable the "RS-232" interface. That is, the 4-wire cable that connects to your computer or terminal. If you don't have this and ARE using a teletype, let me know and we can get you out of the stone age. When you re-install the boards, DON'T connect the K10 connector by mistake. You might want to put some tape around it to prevent that. Now, once you have all the boards out of the main group, also take out the power supply board, which is separate, off to the right, and clean it too. It never hurts to do this every month or two, especially if you use a mist coolant or have a dusty shop area.
Once tht boards are all done, you can either let them sit overnight to dry (at least) or dry them with a hair-dryer set on LOW. DO NOT USE A HEAT GUN intended for thawing pipes as too much heat is clearly bad for the connectors and components. Again, I have to caution, DO NOT USE AN AIR HOSE to dry the boards. It will drive any remaining dirt particles deep under the components where they will just cause problems later. Besides, you will blow off the plastic dust caps and blow water INTO switches. Enough said. Be warned.
Once you have them dry, Re-check them, you can't be too careful. Now inspect the card cage and fans. They are at the bottom of the card cage and collect a lot of s**t over time. If they don't turn freely, they probably aren't running, or aren't running up to speed. If necessary, replace them. If you aren't good at puzzling out how to do it, call in a service man. Expect to pay him $200-300 or more for a visit, plus parts. So think about it. It's not rocket science to remove the fan unit, just hard, dirty work. I think they are 220 volt, so check, Contact me for assistance, I've done it, but it's too complicated to explain in an e-mail. Wipe out any goo and gunk that may be in the card guides. You can use electronic component cleaner spray (several types available, try Radio Shack or McMaster-Carr Company,
www.mcmaster.com) to clean up the female connectors at the back of the cage. Don't leave them all gunky and just put the nice clean boards back in. It's a waste of time. Spray, wait, wipe. Spray one final time, and you MAY use an air hose to dry them, carefully.
If the fans seem OK, and don't take that for granted, put the cards back in. They only go one way up, component side to the right. Some of them may be bowed, and you'll have to guide them into their respective connectors. Push on the edge of the board HARD to seat them all the way in. If it doesn't go, you've got something wrong. Take it back out and start over. Make sure the letters above the slot agree with the legend on the board. Some units may have labelled but unused slots. Double check each board matches with it's slot when installing it. As you put in each board, re-insert the connectors. Again, if it wasn't used, DO NOT re-connect the K10 connector. (BTW it is a connector with only a couple wires, whereas the others in that string have more wires). After you have all the boards in, put the retainers back on with their 1/4 turn screws. If the filters were dirty, replace them. Don't use furnace filters. You can get 1" thick filter media from McMaster-Carr company that works just as well as the expensive commercial filters. E-mail me for the stock number. Don't put the covers back on just yet. Turn on the power to the machine. Check to make sure the fans are running, both the 3(?) under the card cage and the one on the back of the machine. If they are not all running, they should be fixed. Simple as that. You can get suitable replacement fans from McMaster-Carr, or any number of surplus places, like Allelectronics.com, Marlin Jones (MPJA.com), or others. Be certain to get the correct voltage rating. You'll have to get them out and look them over. I can help if you e-mail me. If the fans seem OK, put the covers back on and let the machine set for several hours with the air circulating. Then test the machine. Your problems will "probably" disappear. (If not, at least you have a cleaner machine and the service man will thank you.) If your machine runs, use it for a while before deciding to retrofit it. I can help you interface your PC for uploading and downloading and editing programs, and the controller should do well enough for a beginner to use until he's more seasoned.
I also have some other suggestions that may make your life easier with this machine, e-mail me if interested and I'll post some of them here.
Fred Howe
06-16-2005, 03:52 PM
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