Kürzlich habe ich ein 32K Speichermodul für den HP-71B erstanden, bei dem eine kurze Bedienungsanleitung dabei war. Alles mehr oder weniger selbstverständlich, aber vielleicht doch hilfreich, um ungewollten Datenverlust zu vermeiden.
CMT-71-32R RAM Module for the HP-71
-----------------------------------
Instructions
------------
NOTICE
------
Corvallis Microtechnology, Inc. assumes
no liability resulting from any errors or
ommissions in these instructions, from the
use of the information obtained herein,
or from the use of the CMT-71 Plug-In Mo-
dules or the CMT-71-P01 EPROM Programmer.
All Rights Reserved
Copyright 1986 by
Corvallis Microtechnology, Inc.
INTRODUCTION
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The CMT-71 RAM plug into the front Ports
of the HP-71B. The maximum extra memory
permitted by the use of the CMT-71 Memory
Modules is the following:
4 CMT-71-32R = 128K bytes of RAM
Section 1
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Installing and Removing the Memory Module
Caution:
* Turn off the HP-71 before you install or
remove any module.
* After removing a module, turn the HP-71
on and off so it is ready to accept
another module.
* The contents of the CMT-71-32R are not
backed up by battery when removed from
the HP-71.
* Because there is a chance of memory
loss, it is good practice to back up
important files before installing or
removing any module.
To insert a CMT-71 Memory Module:
1. Turn off the HP-71 by pressing (f)(on).
2. Hold the CMT-71 Memory Module with the
broadest side facing up, and the connector
slot aimed towards an open HP-71 front port.
3. Push the module all the way into the port.
To remove a CMT-71 Memory Module:
1. Turn off the HP-71 by pressing (f)(on).
To prevent memory loss, FREE PORT the
CMT-71-32R before removing it from the
port.
2. Use the fingernails of your middle and
ring fingers to get hold of the lip on
the underside of the module, and pull
the module out of the port.
3. Turn the HP-71 on and then off.
4. Insert a blank module into the port to
protect its electrical contacts.
Section 2
---------
The CMT-71-32R RAM Module
When plugged into a front port of the HP-71,
each CMT-71-32R Module adds 32K bytes of RAM
to the 17.5K bytes of the HP-71 internal RAM.
Up to 128K bytes of extra RAM can be thus
installed in your HP-71. (See Section 1 for
instructions on installing and removing the
CMT-71 modules.)
Like the HP-71 RAM, the CMT-71 RAM can be
used as Main RAM or Independent RAM.
Main RAM
--------
As soon as the CMT-71 is plugged into a
front port of the HP-71, its RAM becomes
part of the Main RAM. This can be verified
by executing MEM.
Main RAM is used for the operations of the
HP-71. Therefore, be sure to declare the
CMT-71 RAM as Independent RAM (see below)
before removing the module from the HP-71.
Otherwise, the entire Main RAM will be
cleared when the module is removed.
Independent RAM
---------------
The CMT-71 RAM can be set aside as Indepen-
dent RAM by executing:
FREE PORT (port number)
The contents of the Independent RAM are not
disturbed by the operations of the HP-71.
Note that the CMT-71 RAM can be FREE PORTed
only as a 32K byte block.
The CMT-71-32R retains its memory contents
while plugged into an HP-71 with proper
battery level. It does not contain a battery
to back up its memory when unplugged from
the HP-71. Because of the CMOS static RAM
used, its standby current is typically less
than 2 uA.
Section 3
---------
Care of the Unit
* Always turn off the HP-71B before you
install or remove any module.
* Keep the electrical contacts of the module
clean. Do not insert any foreign object
into the slot for the electrical contacts.
* Store the module in a clean, dry place.
* Observe the temperature specifications:
Operating : 0 - 45 degree C
Storage : -20 - 55 degree C

4x RAM Chips in serial of 32KB could be in 1 port: do you have such 128KB RAMs?
No, I don’t
What are the chip description (or list of parts + electronic shemata in order to see the connections) inside the front port RAM-modules?
32KB = 4*8KB chips ? with other control chips on the PCBs?
I don’t know. Never opened one. The most complete description of HP-71B peripherals can be found here:
https://www.hhcworld.com/files/HP71COMPENDIUM/DOC/HP-71B_COMPENDIUM.pdf
However, even there you don’t find any specs of the chips. I guess that would be a question to ask on MoHPC forum:
https://www.hpmuseum.org/forum/