From: laubfrosch@tron.gun.de (Dieter Rosenhagen)
Newsgroups: comp.dcom.modems
Subject: Re:Larger EPROMs for ZyXEL 1496S (Rev. 6
Organization: TRON Public Mailbox, Neurath, Germany
Date: Sat, 22 Aug 92 16:04:00 +0200

Am 17.08.92 um 11:22 schrieb g16l%alf.zfn.uni-bremen.de@USENET.ZER unter dem Betreff Larger EPROMs for ZyXEL 1496S (Rev. 6):

-> From: g16l@alf.zfn.uni-bremen.de (Olav Brinkmann)
-> Subject: Larger EPROMs for ZyXEL 1496S (Rev. 6)
-> Message-ID: <g16l.714050390@alf.zfn.uni-bremen.de>
-> Organization: Univ. Bremen, Informatik
-> 
-> Hello,
-> 
->  I'm going to put the larger EPROM sockets in my ZyXEL 1496S. The board is
-> REV 6. Will there be any problems and do I have to consider anything
-> special when installing the sockets?
-> 
-> MfG Olav
-> --
-> [ Olav Brinkmann                    E-Mail  : ob@hb.maus.de              ]
-> [ Uebern Berg 27                    Maus-Net: Olav Brinkmann @ HB        ]
-> [ W-2875 Ganderkesee 2, Germany     Voice   : +49-4223-8701              ]
-> [______________________________________ ...!uunet!unido!uniol!maushb!ob _]
-> 
## Ursprung : /ZyXEL-Infos

U-1496 Series Modem Firmware Upgrade with 1Mbit EPROM
-----------------------------------------------------

The 1Mbit EPROM has 32pins while the 512K EPROM has only 28 pins.  Among the
four additional pins the 1M bit EPROM has, only pin 2 and pin 32 need signal
correction, pin 1 and pin 31 have no connection inside the chip.  If you put 1M
bit EPROM chip in front of you with pin 1 on the lower left corner, the 28
pins on the right have the same signal connection as the 512K EPROM chip.

There are three cases for 1Mbit firmware upgrade:

(1) There are already a pair of 32pin sockets installed on the modem main
    board.

    Just install the 1Mbit EPROMS in the 32-pin sockets.  Note that there
    are no pin sockets for pin 1 and pin 31, no connection is needed for those
    two pins.

(2) 28-pin sockets on the modem board but pin holes on the board exist for
    pin 2 and pin 32.

    Solder in two single-pin sockets for pin 2 and pin 32 and you can install
    the 1M bit EPROM.  You need some skill to solder the single-pin socket.  It
    is better to use a SIP 8-pin single-row pin socket as an alignment tool.
    Plug the single-row pin socket into the existing socket and the single-pin
    socket you want to solder and it will hold the single-pin socket in place
    while you solder.

(3) 28 pin sockets on the modem board and no pin hole exists on the board for
    pin 2 and pin 32.

    We do NOT recommend to install 1Mbit EPROM on this case.  You can do the
    following hardware modifications but it will void the warranty and it is
    difficult to remove and reprogram the EPROMS.

    (a) Solder a jump-wire to short pin 32 and pin 30 of the EPROM.
    (b) Install the 1Mbit EPROMS on the 28-pin sockets with the left 4pins
        outside the sockets.
    (c) Solder a wire to connect pin 2 of the EPROM to pin 45 of the MC68000
        and solder a wire to connect pin 30 and pin 32 of EPROM.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Bye,
Laubfrosch.

>>>ZERBERUS-POINT FROM A.U.G.E. 4000 - LAUBFROSCH@TRON.ZER<<<
>>> laubfrosch@tron.gun.de | Dieter Rosenhagen (2:242/21.15)
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