Subject: Tech Tip: substituting 6116 for 5101
From: Anastasio <[email-masked]>
To: Barry Beadman <[email-masked]>
Date: Wed, 12 Jan 2000 08:53:28 -0500
Newsgroups: rec.games.pinball

I found this somewhere on the net or in r.g.p. Instructions for replacing
the 5101 chip with a 6116. You need to read it with a fixed width font
(Courier):

How to replace a 5101 with a 6116

Quick introduction:

The 5101L is a low power CMOS memory which is used in some MPU units as non
volatile (battery powered) memory for storing high scores, etc. While there
doesn't seem to be any problem sourcing them in the States, I had trouble
trying to get hold of one in the UK. What follows is a description of how to
make a simple adapter which will
allow you to replace a dead 5101 with a readily available alternative,
without modifying your MPU board, and save you money at the same time (in
the UK, at least).

Just to clear up any confusion: If your machine is working OK, then:
*there's no reason to do this*
(It won't make it better, stronger, or faster)

Alternatives to 5101

The 5101 is a low power CMOS stores 1024 bits as 256, 4bit 'nibbles' About
the smallest capacity, widely available chip which could replace it is the
6116 which stores 16384 bits stored as 2048, 8 bit bytes. It's low power
CMOS, with 100ns access time, standby current 10na, and data retention
guaranteed down to 2v. Because the 6116 has more data and address lines than
the 5101, we can play a few games to
make life simple when making an adapter.

One thing about the 5101 - It has separate data in and data out pins. The
6116 hasn't. This conversion only works where these inputs and outputs are
connected together - Check your board, pin 9 should be linked to pin 10, 11
to 12, 13 to 14 and 15 to 16.

You will need:

A 6116 memory chip. Suffix letters don't matter, as long as it's described
as *low power* CMOS.

A 24 pin, 0.6" pitch IC socket to suit the 6116

A piece of 0.1" matrix strip board approx 12 holes square

22 thin PCB solder pins / lengths of tinned wire / wire wrap pins

Possibly a 22 pin, 0.4" pitch socket

(Remember, you can always chop down bigger sockets)

What you have to do

The idea is to make up a 'piggy-back' board to adapt a 24 pin, 0.6" pitch
6116 chip to a 22 pin, 0.4" pitch 5101 socket:

     VIEW WITH STRIPS ON UNDERSIDE
 ______________________________________
|                                      |      strips run this way
|  .  .  .  .  .  .  .  .  .  .  .  .  |     <===================>
|       1     1                        |
|  .  .  O  . [o] x  O  .  .  . [o] +  |      . hole in strip-board
|             I I               I I |  |
|  .  .  O  . [o] x  O  .  .  . [o] |  |      x break in strip on
|             I I               I I |  |        underside
|  .  .  O  . [o] x  O  .  +  x [o] +  |
|             I I            \  I I    |    [o] IC socket pin
|  .  .  O  . [o] x  O  +  x  + [o] .  |        soldered to board
|             I I        \      I I    |
|  .  .  O  . [o] x  O  . \.  . [o] .  |    [ ] IC socket pin cut off
|             I I          \    I I    |
|  .  .  O  . [o] x  O  .  .\ . [o] .  |      O PCB pin protruding on
|             I I            \  I I    |        *underside* of board
|  .  .  O  . [o] x  O  +  x  + [o] .  |
|             I I       |       I I    |  + - + Wire link (between
|  +  .  O  . [o] x  O  +  .  . [o] .  |        holes marked '+')
|  |          I I               I I    |
|  |  +  O  . [o] x  O  +  .  . [ ] .  |
|  |  |       I I       |       I I    |
|  |  +  O  . [ ] x  O  +  .  . [o] .  |    Note: no break between pins
|  |          I I               I I    |          11 & 12 of the 5101
|  |  .  O  . [ ] .  O  .  .  . [o] .  |
|  |          I I               I I    |
|  +  .  .  . [o] x  .  .  .  . [o] .  |
|                                      |
|  .  .  .  .  .  .  .  .  .  .  .  .  |
|                                      |
|______________________________________|

         END VIEW (to make things clearer)

                    __________
                 /-(XXXXXXXXXX)-\   <------- 6116, happy at home
                |                |
               [X]==============[X]  <------ modified 24 pin socket
======================================== <-- strip board
         I           I
         I           I <--- Pins to fit into 5101 socket
         I           I

The most awkward part is arranging some PCB pins, lengths of thickish tinned
wire, or whatever to stick out of the bottom of the board, to plug into the
5101 socket. If you can get hold of 0.7 mm dia PCB pins, then push these in
from the component side of the board, and solder in place. Alternatively,
get the optional 22 pin socket, push 1/2" lengths of tinned copper wire into
all its holes, and feed these
through the stripboard. Trim off flush with the top of the board after
soldering. The socket with the wires in it can then be plugged into the
existing 5101 socket, without having to align 22 bent bits of wire. (I used
wire wrap pins, and had to force them into a cheapy 22 pin socket)

 The official order of construction would be:

1 Break tracks where indicated (14 places)
2 Install 'pins' (22)
3 Install wire links (7) - note that two run diagonally
4 Modify the 24 pin socket by cutting off pins 10,11 and 16. These
  must not contact anything:

  1  [o]===___===[o] 24
     [o]         [o]
     [o]         [o]
     [o]         [o]
     [o]         [o]   view is from *above* (pins down), as is normal
     [o]         [o]
     [o]=========[o]
     [o]         [o]
     [o]       ->[ ]<-
   ->[ ]<-       [o]
   ->[ ]<-       [o]
     [o]=========[o]

5 Install modified socket
6 After checking everything, plug board into 5101 socket, plug 6116
into board and go.....

Unofficial order of construction:

Modify socket, solder it in, saw out 'spreaders' so you can get at the board
to install pins and links, use screwdriver to make track breaks because
you've got a blob of solder next to where you want a break so the rotating
cutter won't work, plug in, unplug, check board and find short, pray you
didn't break anything, plug in again, and go.

(A friend told me this ;->)

Notes:

The CS1 (active low) OE and WE signals are fully implemented. The CS2
(active high) line is patched to one of the address lines of the 6116, so it
is theoretically possible that the chip will be active when it shouldn't be,
this doesn't matter, as any data written during this time will be diverted
to an un-used area of memory. Data cannot read unless the OE line is low.
(In the case of my machine, CS2 was
tied to the reset line, so was always high, anyway).

It might be an idea to fit a 100nf capacitor between pins 12 and 24 of the
6116 socket (good practice), also I get a vague feeling that the un-used
data lines should be connected (via 1meg resistor, say) to either ground or
+5v, although this would make the wiring more complicated.

It worked for me, if anyone manufactures them for profit, I want my fee.

Andy                             ([email-masked])

End Andy's post--------------------------------------------------------

Britt Brooks
[email-masked]

Barry Beadman wrote:

> Does anyone out there know how to substitue a more modern, reliable sram
> for the old 5101?
> The main problem is that the old 5101 has separate data in and out pins.
> are the chip select pins different for those two conditions? I assume we
> cannot simply connect the two data pins together.
> I cannot find the datasheet for the 5101 ram anywhere. does anyone have
> a scan?