dpz@topaz.RUTGERS.EDU (David P. Zimmerman) (07/29/86)
I have a 256K Amiga with no immediate plans to upgrade (lack of
funds), so I want to make the most of what memory I have. I'd like to
know how much memory the following take up under Workbench 1.1 and
1.2b4:
Loading in Workbench
Starting a new CLI
Keeping the image of a disk around
Default space needed for RAM:
Anything else that may take up memory
Thanks for any responses!
David
--
David P. Zimmerman "Unix RULES!!!" - anonymous
Arpa: dpz@topaz.rutgers.edu
Uucp: ...{allegra | harvard | seismo | sri-iu | ut-sally}!topaz!dpzrobinson@shadow.Berkeley.EDU (Michael Robinson) (07/30/86)
In article <5452@topaz.RUTGERS.EDU> dpz@topaz.RUTGERS.EDU (David P. Zimmerman) writes: > >I have a 256K Amiga with no immediate plans to upgrade (lack of >funds), so I want to make the most of what memory I have. Suggestion: Make the most of the money you have. The following is an article a friend downloaded off of compuserve. It describes how to upgrade to 512k for about forty bucks. The instructions are good--I know of three Amigas at least that are running 512k with this upgrade. Caveats: This is *not* an officially sanctioned upgrade, it voids the warranty (so hang loose for 3 months if you're paranoid), and I claim no responsibility whatsoever for the accuracy or suitabilty of what follows. It is a simple case of file transfer--I have nothing to do with the content. /*****************************BEGIN UPGRADE ARTICLE******************** Here's how you can upgrade your Amiga to 512K without spending $200 for the Model 1050 Ram Cartridge, using the time-honored piggyback hack. Piggybacking refers to the technique of installing a new memory chip literally piggyback on an existing memory chip in your computer. Generally all the pins on the new chip are electrically connected to the chip below, except for one line, which is connected with fine wire to some other point in the circuit. Should YOU attempt the piggyback upgrade? It is quite a bit cheaper than the 1050 ram board. I recently (Dec. 85) purchased all the required chips for $44, so you could save over $150 doing the upgrade. Chances are good that these chips will get cheaper as time goes on, although these aren't the ordinary "jellybean" 256K ram chips that have reached commodity status. Rather, they are "64k x 4" chips, as opposed to the more common "256k x 1" chips. Right now they are about twice as expensive as the latter. The bad part is that you will void your warranty and, since you will be soldering on the main Amiga printed circuit board, you risk damaging your new pride and joy. This does require a fair amount of manual dexterity and soldering experience. If you have any doubt about your ability to do this, PLEASE DON'T ATTEMPT IT. If you don't know a nippy cutter from a glomper clip, this ain't for you! You know, really $200 is not a bad price at all for the 256K ram board. have you seen what Apple charges for Mac upgrades?! If you're still with me, here's what you'll need: (8) 256K rams, 64K x 4, NEC 041464-15, HM50464-15 , etc. Needle nose pliers, nippy cutters, low wattage soldering iron (around 25 watts), wire-wrap wire, aluminum foil, phillips screwdriver (milk of magnesia and vodka), alligator clip-leads. I ordered the chips from Microprocessors Unlimited...excellent service! Spread the aluminum foil over your work surface. These rams are EXTREMELY static sensitive. keep them in the tube until the last minute. Unplug the Amiga from the wall. There are several screws in the bottom of the Amiga case recessed into deep wells. Remove them. Remove the top half of the case. (There are some stubborn little clips molded into the two halves of the case holding it together. You may have to pry a bit.) Admire the signatures of all the Amiga gurus molded into the top half of the case. Remove the top half of the RF shield. There are approximately nine thousand small screws holding it on. Now you should be looking at the main printed circuit board, heart of the Amiga. Notice the large, ugly, extra circuit board mounted over the top of the main board. This is the WCS. This board contains another 256K of memory used to hold the contents of the kickstart disk. Notice how expensive it looks. This type of add-on board is sometimes called a KLUDGE. This particular kludge happens to be right smack dab in our way if we are trying to get at the main memory chips, which we are. At this point you should use alligator clip leads to ground the Amiga to the aluminum foil, and attach yourself to the aluminum foil, either by connecting your metal watchband to the foil with a clip lead, or by keeping a part of your body in contact with the foil. Remove the phillips screws holding the WCS board to the main board. GENTLY pull the WCS away from the main board. Place the WCS board out of your way on the foil-covered work surface. Look for the eight memory chips on the main board numbered U1B,U1C,U1D,U1E,U2B,U2C,U2D,and U2E. These are the main 256K "chip" memory. Next, locate two chips numbered U1H and U1I. These are address decoder chips. We will attach two wires to each of these chips. Plug in the soldering iron. It would be a great idea to keep the iron in contact with the aluminum foil while not in use, so it can't accumulate a static charge. Use the nippy cutters to strip a tiny bit of insulation from the wire wrap wire. Strip just enough to 'tack' solder the wire to an i.c. pin - maybe about 1/32". Attach a 6" length of wire-wrap wire to pins 12 and 13 of both U1H and U1I. If you aren't sure where pins 12 and 13 are, you shouldn't be doing this! Now prepare your new ram chips for piggybacking. To do this, you'll have to carefully bend the rows of pins inward. When they come out of the tube brand new, the pins not at right angles to the chip, but bent slightly outward. I usually lay chip sideways on a FLAT surface and push the chip against the surface, bending the entire row at once. Don't bend them in very far. Remember, they have to press down over the existing ram chips. If you bend the pins too far inward, this becomes very difficult. Keep in mind the static electricity problem!! When you have the angle right, all the pins should squeeze tightly against the respective pins of the chip beneath it. When you are satisfied that this is the case, use the needle nose pliers to bend pin #16 upward so that it straight out from the side of the chip. We will be attaching wires to pin 16 of each piggyback ram. Piggyback all eight chips in this fashion, with pin 16 of each piggyback sticking straight out. Make sure each pin is tightly hugging the chip below. Now it's time to do the actual wiring. Cut four 1 1/2" pieces of wire-wrap wire and strip about 1/4" insulation from each end. Each end of these wires will connect to a pin 16 sticking out the side of your piggy back chips. Here's where to put these four wires: Connect pin 16 of piggyback at U1B to piggyback at U1C. Connect pin 16 of piggyback at U1D to piggyback at U1E. Connect pin 16 of piggyback at U2B to piggyback at U2C. Connect pin 16 of piggyback at U2D to piggyback at U2E. Use a very small amount of solder on each connection. Now we'll be connecting the free ends of those 6" wires you attached to U1H and U1I. As you connect these, cut them to the proper length. Leave enough slack so you can neatly route the wires along the surface of the board. Here's where to hook them: Connect the wire from U1H, pin 12 to pin 16 of piggyback chip at U2C. (note that there's already a 1 1/2" wire connected here!) Connect the wire from U1H, pin 13 to pin 16 of piggyback chip at U1C. (same story here.) Connect the wire from U1I, pin 12 to pin 16 of piggyback chip at U2E. (ditto) Connect the wire from U1I, pin 13 to pin 16 of piggyback chip at U1E. (similar situation) That completes the wiring. You may want to reassemble the computer at this point to test it, just to make sure your new rams are good. Or, you may go directly to the next step, soldering all the piggyback pins on. If you did a good job of pin bending, all the piggyback pins (except #16, of course) should be in good electrical contact with the original Amiga rams. This is not good enough for long term operation, however, and you will have to lightly solder each of the pins. As you do this, use a very small amount of solder on each pin, making absolutely sure that you get good solder flow to the pin below. This is where the aforementioned soldering experience really comes into play. It also helps to have a very slender tip on your iron. Be especially careful working around your wire wrap wires. We're almost done. Very carefully re-install the WCS board over the main board. I used a pocket mirror to look underneath the make sure all the pins were properly inserted into the headers. When you're sure everything is lined up press down firmly to seat the connectors. Installing the WCS can be a little tricky. Double check that everything is in place. You're done! Plug it in and try it out before replacing the RF shield and case. If it doesn't work, PANIC. I warned you it wasn't foolproof! You just ruined a $1300 dollar computer! Seriously, If you've done this sort of thing before, everything will go just fine. Piece of cake. Enjoy your $44 ram upgrade! Tim Jenison 71515,710 \*****************************END UPGRADE ARTICLE*************************** Enjoy. ------------------------------------------------------------------------------ Disclaimer: UNIX is a trademark of Bell Laboratories Some assembly required All Thebans are liars The Surgeon General has determined that smoking is hazardous to your health I was holding it for a friend "This has been another helpful hint for living from the commitee's almanac." Mike "programmer with a screwdriver" Robinson USENET: ucbvax!ernie!robinson ARPA: robinson@ernie.berkeley.edu