Back to my Akai 32 Meg memory board page.
I wrote this in reply to an enquiry on the Akai Sampler Discussion List:
Someone wrote:
> I finally found an extra 8 Mb memory board for my old
S1000-KB.
> Now there´s only one problem: I´m a complete
technical
idiot.
> Where should I put the darn thing?
Since you are a "technical idiot", please be a wise one and give
your
sampler, the memory board and these instructions to a technician,
rather
than risk your life and the integrity of the sampler by opening
it up
yourself! In the meantime, keep the memory board wrapped
in aluminium
foil.
I used to make 8 Meg cards for the S1000/S1100. Check my page:
http://www.firstpr.com.au/rwi/smem/
for details of my cost-effective 32 Meg cards for these samplers
and for
the S2800/S3000/S3200/CD3000 machines as well.
For both the S1000 and S1100 (the S1000-KB would be identical to
the
S1000) there are two issues regarding memory board installation:
1 - Placement of the boards in the correct slots.
2 - Setting jumpers (S1000) or switches (S1100) on the
motherboard
to make the machine accept 8 Meg cards in
addition
to or
instead of 2 Meg cards.
This information is adapted from the documentation I provided
with
my 8
Meg cards - which was based on Akai instructions, the instructions
which
came with other memory boards and my experience. I believe
it to be
correct.
Before giving those details, two notes:
1 - The Akai and other brands of 2 or 8 meg cards are rather
dodgy in the S1000 and S1100 since the
motherboard's
signals,
when applied to those cards, violate the timing
requirements of
the RAM chips on the cards. So if the
chips did not work properly
it would not be surprising. A description
of the problems
would only make sense to someone who understands
DRAM timing
diagrams.
Consequently, Akai and other memory boards do
not always work
correctly - particularly when the sampler gets
hot. (Some people's
samplers get *extremely* hot because they are
in racks with no
ventilation or other way of dissipating heat.)
I redesigned my 8 Meg boards to overcome this
timing problem. Still
there are many other challenges to a designer
of such boards,
such as the Address/Data bus on the S1100 having
a bunch of
capacitors on the motherboard (an Akai fudge
to reduce the
timing problem just mentioned) which can cause
severe ground bounce
in the memory board when it reads data from
RAM onto the bus.
My 32 Meg boards completely overcome the
timing,
ground bounce and
all other problems I am aware of.
2 - My 32 Meg boards behave like four 8 Meg boards, and it does
not
matter what the motherboard jumper/switch
settings
are. These
boards typically dissipate less heat than four
2 or 8 meg boards.
Now to the jumpers, switches and board arrangements. This
information
is believed to be good - but it is your responsibility what you
do with
your sampler. This information is sufficient to assist an
experienced
technician - it is *not* intended to encourage people who don't
know
what they are doing work on a dangerous (mains voltage) and delicate
(for many reasons, including static electricity) machine like an
Akai
sampler. *Do Not* request further information to help
you! Everything
you need is here - and if you don't understand it, get a technician
who
does understand it to do the work!
S1000 Jumpers
-------------
The machine, by default, is configured for 2 Meg boards
only.
To make
it work with one or more 8 Meg boards, you have to cut two tracks
on the
*underneath* of the motherboard, and install two wires there or
on the
front side. This means you have to lift the entire
motherboard
out of
the machine. This is hard work, since even with all the cables
disconnected, it is a squeeze. Note very carefully exactly
where the
cables go. I seem to remember one of them is labelled on
the PCB
differently from the way it is actually connected.
(I am describing this from memory and by looking at a rear-view
PCB
layout in the service manual. The diagrams below will look
like garbage
if you view this with a proportional spaced font, so be sure to
select
Courier or some other fixed width font instead.)
Near pin 1 and 20 of IC31 are 8 pads in two rows of 4.
Normally,
there
are two tracks connecting two pairs of pads - on the underside
of the
PCB. You need to cut those two tracks and install two small
jumper
wires to wire up the other two pairs of pads.
Initially, looking from underneath the PCB, with the rear to
your
left
and the left of the PCB to the top, you have:
O--O O--O
|
|
O O O O
Cut those track and wire it up so that it becomes:
O--O O--O
| |
O O O O
Normally, W12 and W13 drive D0 (pin 1) and D1 (pin 2) of
IC32.
The
changes make W14 and W15 drive these pins instead.
S1100 DIP Switch settings
-------------------------
If you are using one or more 8 Megabyte boards, then you must
set
some
switches on the motherboard - switches 1 & 2 ON and switches
3 & 4 OFF.
If you ever return to using purely 2 Megabyte boards, then set
the
switches back to the factory standard - switches 1 & 2 OFF
and switches
3 & 4 ON.
Board arrangements for S1000/S1100
----------------------------------
Here are what I understand are the the allowable combinations -
which
include some combinations not documented by Akai. The four
memory
"slots" are connectors at the rear right of the motherboard.
They are
numbered right to left, 0 to 3. (Note the S1100 has another
connector,
labelled for the DSP board - which is a big board with a Motorola
DSP56000 chip on it. This is not a memory board "slot".)
The allowable combinations of purely 8 Meg boards are:
Slot 3 Slot 2 Slot 1 Slot 0
8
8 8
8 8 8
8
8
8
8
I assume the same pattern should be followed if you are using
only
2 Meg
boards - but make sure the jumper/switch settings are for 2 Megs.
If you are using one or more 8 Meg boards, set the
jumper/switches
as
noted above. The allowable combinations of mixed 8 and 2
Meg boards
are:
Slot 3 Slot 2 Slot 1 Slot 0
2
8 2
8 8 2
2
8
8
2
The only combination not mentioned here is three 8 Meg and one 2
Meg.
You can experiment with that, since there are only four possible
arrangements, but I would guess that 8, 8, 8, 2 would be the best.
- Robin
Back to my Akai 32 Meg memory board page.