a. Soldering the PC Board
In the event you wish to make some changes or
add components requiring soldering, you should have some experience building electronic kits. The PC board pads are small and close together requiring extra caution when soldering to avoid shorts or solder bridges. Use a low-heat, small-tipped, grounded soldering iron. Keep it clean. Use small gauge, rosin core 60/40 solder. Preheat the connection and apply just enough solder to "wet" the connection. Avoid using excessive amounts of solder because it will flow through the plated-through holes and form "blobs" on the top of the card. Excessive or protracted heat from the soldering iron can damage some of the components.
b. Voltage Regulator Option
An unregulated 8-10 volt DC power supply can be used with the COSMAC VIP card if desired. Cut
LK1 on the PC card. Add U28 (a 7805, 5-volt
regulator IC) to the card together with an appropriate heat sink. Make sure the U28 lead pads on the PC DC card don't touch the heat sink. Disconnect the +5 V supply at the + V DC and GND pads and connect your unregulated 8-10 V DC power supply to these pads. This on-card regulator will handle up to I ampere of current and is useful for system expansion. Do not use a plastic cover for your PC card when this on-card regulator option is used. Air How is needed to permit the regulator to operate properly.
c. Additional 2048-Byte RAM Option
To increase your COSMAC VIP RAM to a total of 4096 bytes, add U20-U23 to the PC card by plugging units into the four sockets provided. Measure the power supply current to be sure it does not exceed the capacity of the +5 V DC power pack supplied with the VIP (600 mA). If you require additional power supply current use a regulated +5 V DC supply capable of supplying I ampere or use an unregulated 8-10 V DC supply with the voltage regulator option on the cards.