Replacement RAM – 6116 to suit Stern MPU-200 board
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May 22, 2018
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Replacement RAM – 6116 to suit
Stern MPU-200 board
V1.2 - 17 Dec 2011
All parts of this manual including pictures, schematics & text are ©
Homepin.com and are not to be reproduced for distribution. You
may print this manual & the schematic diagram for your own use
only. The words ‘Bally’ and ‘Stern’ are used to describe various
things in the manual and are the property of the respective owners.
In addition to the parts supplied in this kit you will need a
temperature controlled soldering iron with some fine resin cored
solder and a pair of small side cutters. Nothing else should be
NOTE 1: This assembly should be installed in the board with ALL
backup battery sources removed or damage to the 6116 RAM (and
possibly other parts on the board) may result. This daughterboard
MUST be inserted the correct way around in the socket.
NOTE 2: This memory board can be installed to ANY Bally/Stern
-35 type MPU BUT, it will only work correctly with Stern games
running code in EPROMS that originally required an MPU-200 with
2 x 5101 RAMs. Using this memory board with Bally games or early
Stern games that DID NOT use 2 x RAMs may cause unpredictable
First remove the 5101 RAM/RAMs (if fitted) in positions U8 & U13
on an original Stern MPU-200 or position U8 on a Bally -35 MPU
If an IC socket is not fitted in EPROM position U6 (all boards) then
fit one. We recommend using turned pin sockets for reliability.
Plug in the RAM daughterboard to IC position U6 – observe the
correct orientation (refer pic above).
Run the three connecting wires neatly down the MPU board and
through the unused mounting hole just below U8 (shown above).
Solder the Green wire to pin 20 of the U8 IC position. Solder the
Brown wire to pin 19 of U8. Locate the memory battery positive (+)
voltage and solder the Blue wire to that point. Shown above is the
correct place on a Homepin MPU-35. This point will differ on
original Bally and Stern PCBs.
Check closely for shorts between tracks and, ideally, ask a mate to
double check that you have all the wires in the right place BEFORE
powering the board up. Insert the memory backup battery and
power up the board. If the green diagnostic LED on the MPU flashes
7 times (when installed in a machine or 6 times if not) you know that
this RAM board is working as it is checked at boot by the
You’re now finished – Congratulations!
This document is available for download (in colour) at
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