Shareware Overload/ShartewareOverload.cdr/progm/funkybox.zip/STUFCHIP.DOC

Text File | 1983-05-03 | 15KB | 259 lines

              HOW TO STUFF YOUR OWN BOARDS WITH CHIPS
              By Louis A. Warner, P. E.
              PEOPLE SYSTEMS LTD. -- SOFTWARE (C) 1983

              You have just purchased some of the finest devices
              that have ever been produced. These chips need
              special attention if you want to get the best out
              of them, because they are very easily damaged by
              static electricity, that you and I wouldn't even
              notice. No snap, crackle or pop, but zowie, there
              goes a good chip, destroyed by static electricity.

              There are ways to protect your investment against
              such damage, if you're careful and take your time.
              Before you unpack the chips think of a pettigree
              puppy that you just purchased, and treat it
              tenderly and you'll enjoy. Oh, yes, don't open up
              the chips until you're ready to install them.

              Remember static electricity hates humidity, but it
              loves nylon and synthetic clothing, soft rugs and
              slippery shoes. Static is worse in the dry winter
              weather, and least in the humid summer time.
              Before you unpack your chips, have you read your
              owners manuals for adding chips to the main memory
              or an expansion board? Refresh your memory and
              plan your project and you'll do it easily. It's
              really not very hard to do and unless you get
              rough with your equipment there is little you can
              harm if you take precautions. You will need a big
              sheet of aluminum foil, a spray bottle of water, a
              boiling teakettle and some light hobby tools,
              flashlight, magnifier, pad and pencil along with
              the manuals etc.

              A clear, clean kitchen table on a linoleum floor
              where the light is very good is a fine place to
              operate on the patient. Take your computer cabinet
              off to get at the board you're going to stuff.
              Read your manuals or ask your buddy's help to get
              it unbuttoned. On the IBM-PC there are two large
              screws in the lower rear corners, near the curve
              at the bottom of the back. Slide the cover forward
              and put it aside. Vacuum the fan and inlet areas
              carefully, but don't let the air from the vacuum
              stir up any dust in the room. Wiping the fan
              blades with a tiny brush will help it do its job.

              Remove the rear hold down screw from the expansion
              board and gently raise the board from the bus
              socket on the mother board. Place a large piece of
              aluminum foil flat on the table to touch and
              ground yourself on when you're working on the
              chips. If you have a battery powered board (clock
              etc) remove the battery. You are now ready to open
              up your chips and set them into the open sockets.
              Review your conditions again. Shoes off, tea
              kettle boiling, dog and cat out of the house, kids
              gone to the movies, you are ready to operate,
              Doctor.

              What do you do in the winter or when the humidity
              is real low? Wait for a rainy day or raise the
              humidity with a vaporizer in the room. Don't wear
              synthetic clothes. But use a spray bottle to keep
              from getting too dry. Mist your clothes and the
              floor and chair seat (usually plastic too) with
              water to keep it from generating static. Don't
              work on rugs, if possible, or else spray them with
              static guard and water mist. Look-out for nylon
              lingerie whether you are stuffing a board or
              whatever. Don't get your computer wet.

              You have unwrapped your chips and the board is
              sitting on the aluminum foil waiting for the
              chips. Stand your chips, pins down on the foil and
              examine one carefully, while touching the foil.
              There may be a production number marked on the
              underside, in case you need a reference mark. They
              can also be marked with ordinary pencil lead if
              you write small enough. Note the indentation at
              one end that indicates the number one pin end.
              Find out which way it should go in your board. The
              pins taper outwards and need to be gently squeezed
              together into two straight lines.

              Press the side of the pins (lengthwise) against
              the table to align and narrow down the spacing
              between the lines. Do it again for the pins on the
              opposite side. Now set it on the socket gently,
              check direction for the dimpled end (socket covers
              have been removed, if they existed). Inspect it
              carefully, with a magnifying glass, if available.

              If the pins line up with the contact holes
              properly, then use your two thumbs and steadily
              press it into the socket. You will feel the socket
              grab the pins, but dont try to test its holding
              power. It's hard to get them in but much harder to
              take chips out of the sockets. There are special
              chip tools that are available and are well worth
              the money, if you are going to do much pushing and
              pulling. Or you can use a couple of small
              screwdrivers as wedges. But gently! Now take your
              glass and inspect the chip pins for one that might
              have been folded under when you pressed it in and
              it was not in line with the hole. Inspect each pin
              carefully for a few chips and develop a secure
              feeling that you are doing it right before you
              proceed too far.

              When the board is stuffed with one full set of
              eight or nine chips, (populated as they say) and
              you have reset your switches properly, it is best
              to test, doctor. But first, look around and read
              the labels and signs so that the inside of your
              computer isn't such a strange place next time you
              have to dig under its covers. You probably feel
              like the radio receiver owner, when he first
              changed a tube, years ago. But it's just another
              piece of hardware to get familiar with. Don't
              touch but do look, ask questions, and read the
              manuals. Take a photo or two.

              Now, doctor, lets plug it in and test each set
              before we suture up the patient, and put on the
              cabinet again. Install the operating cables and
              put the boot disk in the A: drive and turn it on.
              Remember that with more memory its going to take
              more self- diagnostic time, so dont be surprised
              if 256K takes over a minute before the CPU
              beeps,"All present and accounted for, Sir". Then
              your normal boot routine should begin. Watch
              carefully for error messages on the screen and
              write them down. If you have parity lights on the
              board note them and shut the power off in case
              there is not a normal boot sequence (except for
              the longer memory check at the beginning.)

              DON'T PANIC -- SLOW AND EASY IS THE GAME -- THIS
              HAS HAPPENED BEFORE AND PEOPLE LIVE THROUGH IT.
              Here's a list of what could be causing a
              malfunction, IF THERE IS ONE!  The switches on the
              board and in the computer could be set wrong,
              recheck them in writing. Have someone else double
              check you. There could be a bad chip. (We'll tell
              you how to look for it). You may have disturbed
              something in your cleaning or reassembling the
              cables and case. Make sure everything is properly
              turned on for the test. There is also the remote
              possibility that the expansion board is defective
              or intermittant in the section you have just
              stuffed. Examine the solder joints on the printed
              circuit board in these areas. Retrace your steps
              and restudy the manuals, check the switches and
              then try it again after a short period. Shut it
              down if it still doesn't boot properly and once
              more check all possibilities. The chip failure
              probability is less than any of the other
              possibilities, especially wrong switch settings.

              Remember there are totals of the PC mother board
              chips, total of the expansion board's memory,
              total of other boards like a C/PM adapter memory
              and then the grand total of all RAM installed.
              Check them by writing them down and see if the
              switches are correctly set, one by one. Then if,
              you find that everything is O.K. but it still
              doesn't work the way it should, continue on.

              Let's see if there is a bad chip. This is usually
              the first assumption, but most often it is switch
              settings or bent pins or bad sockets that make
              intermittant contact or some silly thing like
              leaving the keyboard unplugged. Since taking the
              chips out is a stubborn operation that doesn't
              improve with brute force, let's plan our attack.

              If we have a couple of spare chips we can try them
              in another working circuit on the board and reset
              the switches. Go back to where you started. Ground
              Zero we shall call it. Usually, you dont have to
              pull the chips just reset the switches and try out
              the old chips under the original conditions
              (before stuffing). Put the board in and test it
              again. It's probably O.K. and you haven't done any
              damage. But electronic gremlins aren't called
              glitches for nothing.

              Now swap the new spares to determine if they work
              in the working circuit. Yup, they work O.K. Now
              let's start a planned procedure to reduce the
              confusion and the number of times we have to push
              and pull the same sockets and chips. We don't want
              to damage our board or the chips with too much
              handling or abuse. If you stuffed three sets of
              chips without testing each set and the last one
              shows the parity error then take those out to
              test. Work your way backwards, one set at a time,
              until you get to a working state. Remember to
              reset the switches correctly each time you test
              another full set of chips. You can not test
              partial sets although they can usually remain in
              the sockets if you know they are good. But, when
              in doubt, take them out.

              Now test three chips at a time and mark them. Put
              nine that tested good in the old circuit into the
              next set of sockets. If you only have one extra
              chip, borrow the parity chip, and turn off the
              parity reporting until you locate the bad chip
              (probably only one, IF ANY). By testing your chips
              two or three at a time in the working circuit, you
              can isolate the bad group then test them one by
              one to find the culprit, if there is one.

              When you get through testing and stuffing, you'll
              find there is nothing wrong with any of the chips
              and they all work fine. There apparently was a
              temporary glitche the first time around that
              issued the parity error and it took a while to
              discharge a condensor or change a flag or
              something. That's why, when you buy a pocket
              calculator, they tell you to turn it off and on
              several times, if it doesn't work properly the
              first time.

              Try to keep track of your tests and actions on
              paper so that you can isolate a bad chip or
              convince yourself that it's something else that's
              wrong. Mark the chips with a pencil or note the
              production marks that should identify them
              uniquely. For your own piece of mind when you
              think that you have found a faulty chip, after all
              else is done, test it to prove it's bad in a
              working circuit, one chip at a time.

              Don't be surprised if it tests good now. That's why
              manufacturers call it "burning in". (Finding the
              good and the bad actors). But usually the
              percentage of bad chips is miniscule unless there
              is a run that quality control didn't catch before
              it left the plant, which is almost unheard of. If
              it now works, burn it in. Leave a colored mark on
              any suspicious ones, just in case you need to
              locate an intermittent one in a couple of days or
              so. Keep a written record of them also.

              If you are using the same set of sockets to test a
              lot of chips, alternate the sockets so that the
              same ones don't get all the wear. Be careful not
              to pry against any of the small electronic
              components and damage them.

              Good luck stuffing -- you'll find the experience
              worth while and not hard at all once you get the
              knack of it.