157 lines
8.1 KiB
Plaintext
157 lines
8.1 KiB
Plaintext
MiniSport Laptop Hacker (TM) - Vol #24. November 1994
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To discourage pecuniary interests, Copyright (c) 1994 Brian Mork
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>>> ADMIN
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The MLHacker (TM) series is sized to print out on the front and back of
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a single 8.5"x11" sheet of paper, using 8lpi. You or your print program
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have to add your own page break lines or form feed character. Back
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issues are available from ftp.cs.buffalo.edu in the \pub\msdos\ham-radio
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directory, or on SimTel archives (e.g. oak.oakland.edu in the
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\pub\msdos\packet\mlhacker.zip file).
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>>> MOBILE BATTERY POWER -- CONTINUED
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Last issue, I included part one of Jim Harvey's description of how he
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made a suitable container for the custom battery pack. Here's the
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second and last part. Next issue I'll include his description of making
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a custom battery charger.
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"Now solder the two brass contacts to the prepared PC board header.
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Support the PC board on a small piece of wood, copper side up. Tin the
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board where the contacts will lie, then place the prepared brass
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contacts on the board. Heat, and flow solder between the contact and
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board but don't let it run down the stem of the "T". Check the spacing
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and angle of your contacts on the battery. You can bend the brass to
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fit or reheat the assembly and move the contact a little. You want a
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firm, flat contact with the battery terminals when the header is aligned
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squarely on the top.
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PC Board Header Top View With Battery Contacts Attached
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Notch for battery contact
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----------- v -----------
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Asterisks indicate / |*****| \
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position of contact / ************* \
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/ ************* \
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Insulating Cut --> |===================================|
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on Centerline \ ************* /
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\ ************* /
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\ |*****| /
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----------- ^ -----------
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Notch for battery contact
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Side Edge View of PC Header Showing Contact Position
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(Foil side) *************
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|===============*****===============|
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(Bare side) *****
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***** Battery fits
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***** here
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*****
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"Solder your power cable to the two halves of the header assembly. Use
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red and black wire to keep track of polarity. You MUST use an in-line
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fuse holder close to the battery pack with about a 5 amp fuse.
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Terminate the loose end of the cable with your power connector of choice
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and the contact header assembly is finished.
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"The next step is to wrap the header and the top 2 1/2 inches of the
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battery pack with insulating fiberglass. Inexpensive auto repair resins
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set up quickly, so you must have all material cut in advance.
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"Prepare a piece of fiberglass to cover the top of the battery by
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cutting a 2" by 3" piece of cloth and unraveling about 3/8 inch on each
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of the four edges. This will allow the material to fold down over the
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sides of the battery without wrinkling. Next, cut a 2 1/2" by 6 1/2
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inch rectangular piece, which will wrap around the body of the battery.
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Cut two small 2 1/2" by 1/2" strips. These will help form a channel
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around the molded battery keyway, necessary to ensure later that the cap
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is slipped on with the proper polarity.
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"Open the Condom and starting at the contact end, unroll it down over
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the whole battery. This will protect the battery from the fiberglass
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resin. Slip the completed contact assembly into working position on the
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battery over the Condom, taking care not to tear the latex. Now put a
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bit of half inch wide masking or electrical tape over the brass
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contacts, carefully sealing the tape to the latex on the sides and up
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over the top about 1/8 of an inch. You do not want the Epoxy to bind to
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the contacts in the fiberglass shell, they must be free to move a bit.
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Be sure to observe polarity of your cable at this time, it's easy to
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plug the header on backwards.
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"Wrap string closely around the battery about 2 1/2 inches down from the
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top. This will form a reinforcing ridge at the bottom edge of the
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completed shell. Tuck the loose ends under, or tie an inconspicuous
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knot.
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"You are ready to begin the messy fiberglass process. Spread newspapers
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around everywhere, this stuff is permanent. You should wear old
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clothes, rubber gloves and eye protection.
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"Mix about an ounce and a half of Epoxy resin per the manufacturers
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directions. If you have a 3 or 5 ounce Dixie cup, it's easy to guess
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the amount. Remember, this type of Epoxy sets up in just a few minutes
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so it is important to plan and to have all the pieces of cloth prepared.
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"Paint a thick coat of Epoxy on top of the contact assembly and around
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the edges. Place the unraveled 2" x 3" glass cloth on top and paint
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more liquid on the cloth until it is saturated. Brush the unraveled
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edges down over the sides of the battery. Now apply Epoxy all the way
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down to the string and position the two narrow 2 1/2" x 1/2" strips on
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either side of the molded keyway that runs down the side of the battery
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case. This helps form a matching keyway in the fiberglass shell.
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Saturate these strips with resin, then center the 2 1/2" x 6 1/2" cloth
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over the key way and wrap it around the battery. The bottom edge should
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cover the string and the top edge should overlap the top of the contact
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assembly slightly. Flow resin over all the cloth until it is saturated
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and smooth it out with the brush. Rotate the assembly frequently to help
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keep the fluid from dripping.
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"In about five minutes you will feel the brush start to drag. Continue
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to rotate the battery slowly to prevent drips until the resin has become
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stiff. Set the assembly aside for 4 hours or so to set up. When it is
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solid to the touch, you can gently pull the cap and Condom from the
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battery. The Condom will separate from the fiberglass with gentle
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tugging. Let the shell harden a few more hours and if there is still a
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sticky residue on the inside, wipe it out with a rag and lacquer
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thinner. Cut and sand the bottom edge even at the string and sand any
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rough edges on the fiberglass. Dimples, bubbles or ragged edges can be
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touched up with 5 minute Epoxy cement.
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"Paint the finished shell if you desire, and you're done. I also
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constructed a couple of contactless fiberglass caps to protect my spare
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batteries from shorting out inside my tool box.
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>>> EXTERNAL CGA MONITOR -- WITH COLOR!
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I found a source for Minisport external screens. As you're probably
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aware, the Minisport has the internal logic to drive a Color Graphics
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Adapter (CGA) monitor. The built-in screen, of course, is monochrome,
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but there's a plug on the back to hook up an external, full-color
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screen. Wouldn't it be great to tap into this potential at minimal
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cost?
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Here's what I found: A 5" color monitor, *not* enclosed in any case
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(you'll have to put it in a metal or wood box). From the picture, you
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get a tube and the electronics board mounted in a minimal frame
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arrangement. It runs off from 12 VDC and uses a standard interface
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connector. They cost $69 plus $5 s/h. Advertisements show up in the
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magazine _Midnight Engineering_.
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The small size and mandatory custom enclosure could make for some
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interesting portable setups for use with the Minisport! They're
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available through Timeline Inc., 23605 Telo Ave,, Torrance, CA 90505.
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Technical info line is 310-784-5488. Orders only line is 800-223-9977.
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I have not purchased one of these, and I've not dealt with the retailer.
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I'm bringing it up here only to make known the availability of such a
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beasty. If you purchase one and use it with the Minisport, let me know!
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Please provide feedback! * Direct data 1-509-244-9260
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* ARO Net KA9SNF@ka7fvv.#ewa.wa.usa
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* Internet bmork@opus-ovh.spk.wa.us
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73, Brian * 6006-B Eaker, Fairchild, WA 99011
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