Speed
------
The PowerBook 1400 series computers require 70 nanosecond (ns) RAM. The RAM on the card must be low-profile memory chips.
Which RAM Slot Is Expandable?
-----------------------------
The Apple factory slot is to the left (when looking at the PowerBook computer from the front). This slot should not be modified. RAM cards cannot be stacked on top of one another in the Apple factory slot. This slot already has an Apple RAM card in it when it is shipped from Apple.
The customer slot is to the right (when looking at the PowerBook computer from the front). The customer slot supports and has enough room for two cards to be stacked on top of one another.
Which Type of RAM Card Do I Need?
---------------------------------
To determine which type of RAM card you need to purchase, follow these guidelines:
* If your Macintosh PowerBook 1400 series computer has a total of 12 MB or 16 MB of RAM, that probably** means you have the original factory configuration. Only the original RAM is installed. This kind of configuration means that your customer expansion slot is empty. Two RAM cards can be installed in the customer RAM slot, one on top of the other.
** Note: Apple shipped the PowerBook 1400 series computers in both 12 MB
and 16 MB configurations. However, it is possible that if your PowerBook
has 16 MB, it originally had 12 MB and 4 MB has been added in the customer
slot. The only way to be sure the customer slot is empty is to open the
computer as described in the Users Manual.
If you are not sure how much RAM you have, you can tell by pulling down the Apple menu when you are in the Finder and selecting About This Macintosh.
There is an Apple RAM expansion card available from authorized Apple Resellers for installation in the customer RAM slot. It is called the Macintosh PowerBook 8 MB Memory Expansion Card (Order No. M4506). This card has a passthrough connector which allows another card to be stacked on top of it.
If you choose to purchase a third-party RAM card (not from Apple), you need to ask the manufacturer if the RAM card they sell goes specifically on the top or bottom or if it will go in either position. You may also want to ask whether or not any other companies' RAM cards can be plugged into their card, or if only their brand of RAM cards can be stacked on top of each other.
* If your Macintosh PowerBook 1400 series computer has a total of more than 16 MB of RAM, that means you definitely have more than the original factory configuration. There is already a RAM card installed in the customer expansion slot.
If the card in the customer expansion slot is an Apple RAM card, you can plug another Apple RAM card in on top of it. If it is a third-party RAM card, you need to ask the manufacturer whether or not this particular card can have another card (Apple or third-party) stacked on top of it.
This article was published in the Information Alley on 12 November 1996.