So you have a Mega 2, but would like 4 megs of memory. In the eyes of Atari, you should sell your Mega 2 and buy a Mega 4. However, I disagree that you should have to do this, and thus decided to upgrade "the hard way" instead. If you have had no soldering or de-soldering experience this project is not for you. There are 18 pins on each chip socket, with 16 chips. That's 288 connections, each one has to be de-soldered and then re-soldered perfectly to work well. There are also a few resistors that you must add for a successful upgrade. And now for some legal mumbo-jumbo to keep me off the hook: This upgrade WILL violate any and all warranties on this computer product. I do not promise that this upgrade will work, and hold no responsibilities to the equipment or person doing this upgrade. Ok, enough of that. You will need the following products to do this upgrade: 3-33 ohm 1/4 5% resistors 16-1 Megabyte chips of the same speed as the present ones in your mega 16-18 pin low-profile chip sockets also a pair of needle-nose pliers a pair of small wire cutters a 25-35 watt soldering iron a 30-50 watt solder-sucker iron -or- solder braid a roll of miniature solder a small flathead screwdriver a medium-sized phillips screwdriver a can of solder flux remover a ohm-meter to check for shorts * And most important.... A GROUND (electrical) & A CEMENT OR TILE FLOOR to work on (So that you do not zap all these expensive parts, or your computer). Steps in upgrading a Mega 2 to a Mega 4: 1. Open up plastic case by removing ALL the screws on the bottom of the case first. Then remove the top. Be careful with the clock cable, it is very fragile. 2. Bend the RF shield tabs so that they are strait, and then remove the shield. Note, there is a tab underneath the disk drive that is hard to see (and get to). 3. Unplug the internal disk drive from power supply and drive bus. To remove the power supply plug, use a small screwdriver to pry the connector clasp up. 4. Unscrew the power supply, and unplug it from the board and remove. 5. Turn the computer so that the expansion ports face you. Unscrew all of the screw posts. This is required for you to be able to remove the bottom RF shield. 6. Now, remove the circuit board from the bottom of the plastic case. 7. Remove the bottom RF shield from the circuit board so that you can access the bottom. 8. Turn over the circuit board so that you can start solder- sucking out the solder where the chip sockets will go. This is the trickiest part of the operation. If you have never done this before, find someone else to do it for you (or at least show you how). There will be 16 blank chip areas, this is where your sockets will go. 9. Now, check for any shorts that may have developed in solder-sucking. If there are any, correct them before continuing. 10. Spray some solder flux remover on the back of the board (over a sink, or paper towels). This will allow for a better solder contact. 11. Plug the power supply back into the board and plug in a monitor (DO THIS ON A NON-CONDUCTIVE SURFACE!). Turn the unit on. You should get the normal GEM screen in 30 seconds or so. You of course will not see any drive icons, as you have no drive attached. >> If you do not get this screen, but instead get bombs or wierd patterns on the screen, turn off the computer immediately and check for shorts. Correct these before continuing. 12. Take the power supply back out (I bet you are getting good at this). 13. Now, install the 16, 18-pin chip sockets into the newly solder-sucked holes. Make sure to put the notches in the same direction as marked on the PC board. A trick to keep the sockets in the holes while turning over the board is to bend opposite corner pins outward. You may wish to do one socket at a time, rather than putting them all in and then soldering them all at once. This is your choice :-) 14. Again, put the power supply back in to check for shorts. After checking and correcting problems, remove the power supply. 15. Now you need to install 3, 33 ohm 1/4 watt resistors in the empty resistor sockets located near the chip banks (normally toward the inside of the Mega). The direction does not matter, but they look better if your new resistor's stripes match the present ones. Put them in snug to the board, and then clip off the excess leads. 16. Again, use the solder flux remover to clean up the PC board. This will make your project look more professional, and keep the flux from attracting dust. 17. Now, install all of the 1 megabyte chips, making sure to put the notch in the correct position (Normally pointing to the middle of the Mega). Usually chips come too wide to fit in sockets, use the corner of a desk to gently bend all the pins on one side at the same time. Be very careful not to bend any pins inserting them into the sockets. If you do, use the needle-nose pliers (after touching them to a ground) to straighten the pins. 18. Install the power supply again and test for shorts. After all tests out ok, re-assemble the computer in exactly the reverse that you took it apart. 19. You now have a mega 4! Enjoy. If you have any problems, leave me a message on GEnie to BDHALL. Copyright 1988, Bryan Hall. All rights reserved.