Ref: 09330018
Title: IE3 RAM Upgrade Article for the Link Plus Optimizer software
Date:  7-21-88

Copyright 3Com Corporation, 1991.  All rights reserved.

Date: 10-19-87

EtherLink Plus comes in 4 versions; here are the differences:

ASSY: 1194
1 The earliest board has 128K of memory and sockets to expand to a
  maximum of 256K.

ASSY: 2012
2 The most common version has 128K memory, sockets to expand to 256K
  and board space (no sockets) to expand to 512K.

3 The current version has 128K of memory and sockets for 512K.

4 The new version will have 256K of memory and sockets for 512K.

                      Do it Yourself

Dealers and customers can either purchase 3COM's 3C505-B-128K or RAM
direct from chip suppliers, and populate their own adapters (see RAM
specifications below). 3C505-B-128K can be purchased through an
authorized 3COM Reseller or direct from 3COM's Customer Relations group
(415-969-2099).

Inserting chips bought from 3COM or identified below will not void the
3COM board warranty unless chips are inserted backwards.
   ***   Soldering chips into a board will void the warranty  ***

* Note: Be very careful to not insert chips backward. Look at the notch
* on existing memory chips and be sure to insert all chips facing the
* same direction. A backwards chip will harm the card.

Jumpers do not need to be moved.


____
IIII| <------ Contacts
    |_______________________________________________________________
                                                                    |
EtherLink Plus - Contacts up                  ______________        |
                                             |              |       |
                                  notch -->   >  RAM  Chip  |       |
                                             |______________|       |
                                                                    |
                                                                    |
                                              o-o-o-o-o-o-o-o       |
                               insert         |   Empty     |       |
                                same ----->   |   Socket    |       |
                              direction       o-o-o-o-o-o-o-o       |
                                                                    |
                                                                    |
                                                                    |
                                                                    |
                                                                    |
                    (not  to scale)                                 |
                                                                    |
____________________________________________________________________|


                            RAM Specifications


.br;NEC                 41464-C15
.br;Fujitsu             MB 81464-15P
.br;Toshiba             TMM 41464P-15
.br;TI                  TMS4464-15
.br;Micron              MT 4067-15


Memory Specifications:
   64K x 4 DRAM
   Maximum RAS access time: 150  nanoseconds
   Maximum CAS access time: 75   nanoseconds
   Must support CAS before RAS   refresh

                  Detailed Installation Instructions

          128K RAM UPGRADE INSTRUCTIONS FOR ETHERLINK PLUS

These instructions explain how to upgrade RAM on your EtherLink Plus
adapter.

You must follow different upgrade instructions depending on the version
of your adapter.  The two versions are:

    Model 3C505 (Assembly Number 1194)
    Model 3C505-B (Assembly Number 2012)

The easiest way to identify the adapter is by its assembly number which
is printed along the edge of the adapter opposite the connectors (see
Figures 1 and 2).

Upgrade your adapter by following the instructions given in the
appropriate section below.


Upgrading 3C505 (Assembly Number 1194)

You can upgrade the 3C505 adapter (see Figure 1) from the standard
128K configuration to 256K by following these steps.

Figure 1.  3C505 Adapter (Assembly Number 1194)


1. Before handling the adapter, touch any available metal object, to
discharge static electricity that may have built up on your body.

2. Place the adapter on a flat surface.

3. Insert the RAM chips into the empty sockets shown on the adapter
(see Figure 1).

    a. Position each chip so that the notch on its edge is placed
directly over the notch printed on the adapter.

   b. Line up the chip's pins with the socket holes and press down
firmly until the RAM is in place.


Upgrading 3C505-B (Assembly Number 2012)

The are three versions of the 3C505-B adapter (see Figure 2) each
with a varying number of sockets and installed RAM chips.

NOTE:  Version A is field upgradable to 256K only.  Do not solder RAM
or sockets onto the board or you will void the warranty.  3Com offers
a RAM upgrade service to solder in chips (see Factory Upgrade below).


Figure 2.  3C505-B Adapter (Assembly Number 2012)


Consult Figure 2 to identify the version of the adapter you are using
and follow these steps to upgrade the adapter.


1. Before handling the adapter, touch any available metal object, to
discharge static electricity that may have built up on your body.

2. Place the adapter on a flat surface.

3. Insert the RAM chips into the empty sockets shown on the adapter
(see Figure 2).

a. Install the chips in the sockets designated for the amount of RAM
you want installed as shown in Figure 2.  For example, if you are
upgrading to 256K, install four RAM chips in the sockets marked for
256K.  If you are upgrading Version B to 384K, install eight RAM
chips: four chips in the sockets marked for 256K, and four chips in
the sockets marked for 384K.  If you are upgrading Version C, install
only four chips in the sockets marked for 384K.

b. Position each chip so that the notch on its edge is placed
directly over the notch printed on the adapter.

c. Line up the chip's pins with the socket holes and press down
firmly until the RAM is in place.


                          Factory Upgrade

If 512K of memory is desired for a board that has space for it, but
no sockets, or you would like 3COM to plug memory into your board our
service organization will upgrade any EtherLink Plus to it's maximum
configuration for (ASSY: 1194 to 256K, or ASSY: 2012 to 512K).
