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NeXT Hardware Internal FAQ

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Subject: NeXT-Hardware-Internal-FAQ
Date: 6 Mar 1995 08:39:15 GMT
Organization: Yale University, Department of Computer Science, New Haven, CT
Lines: 495
Approved: [email protected]
Expires: Fri, 7 Apr 1995 00:00:00 GMT
Message-ID: <[email protected]>
Reply-To: [email protected]
Summary: Frequently Asked Questions about NEXTSTEP and NeXT machines.
Originator: [email protected]

Archive-name: NeXT-Hardware-Internal-FAQ
Last-modified: Mon Mar  6 03:03:59 EST 1995
Version: 3.1

These FAQs are under significant construction,
and may well change form and content over the
next weeks.

These FAQs focus on various aspects of OpenStep,
NEXTSTEP, and NeXT machines.  

The FAQs are kept on-line at several ftp sites,

Many FAQs, including these, are available (www, ftp,
email) on the archive site in the
directory pub/usenet/news.answers.  The name under
which this FAQ is archived appears in the
Archive-nameline above.

Within each section each question will be preceded by
a "Subject:" field, allowing news readers to break up
the file into separate questions.  Each question has
its own unique number. Items that appear within
sections are not in any particular order, and get added
and removed over time.  Questions marked with a "+"
are new to this issue, and questions with changes since
the last issue are marked by a "!".

Submissions, corrections, comments, input, etc.,
should be directed to Nathan Janette
<[email protected]>. 

Some important NEXTSTEP & OpenStep Information WWW sites:

NeXT, Inc.


Stepwise NEXTSTEP/OpenStep Information Server


L1.		What can be done about older 030 NeXT cubes that have a fan that turns in the "wrong" direction?
L2.		Can I connect a SONY 2.88 MB floppy to my 68030 NeXT Computer?
L3.		Why does the OD continually spin up and spin down?
L4.		How many colors can NeXT machines display?
L5.		Why is my machine so slow when I run the monochrome and NeXTdimension displays?
L6.		Where to obtain replacement mouse parts?
L7.		Where to obtain extra batteries?
L8.		How to convert a Turbo system to use ADB?
L9.		How to put a 68030 board in the same NeXTcube as a 68040 board?
L10.	How to expand DSP memory?
L11.	How to boot a NeXT without a monitor?
L12.	Two internal hard drives on NeXT Motorolla 68040 slabs?


Subject: L1. What can be done about older 030 NeXT cubes that have a fan that turns in the "wrong" direction?

The fan on older 030 NeXTs cubes sucks air out of the back of the cube
which means that it draws unfiltered air in through the optical disk on
the front of the cube.  This causes optical disks to succumb to dust must
sooner than cubes with the later version fan which turns in the opposite

It is okay to reverse the direction of fans in these machines.  If you
have many third-party cards installed in your cube or an older processor
board, you may wish to consider not reversing fan direction (overheating
could become a problem).  In any case, do not reverse the fan's polarity,
only reverse the fan assembly itself.  

Try to obtain the cleaning kit and OD filter retrofit parts also.


Subject: L2. Can I connect a SONY 2.88 MB floppy to my 68030 NeXT Computer?

The SONY MPX-111N internal 2.88 MB floppy drive which was shipped with
all the 68040 NeXT machines is *not* a SCSI device, therefore there is no
way of connecting that particular drive internally on a 68030 system.    


Subject: L3. Why does the OD continually spin up and spin down?

A big problem with the Canon optical drives is that air flows through the
drive to cool it.  Dust accumulates inside the drive causing it to fail
with the continuous spin-up spin-down syndrome.  NeXT as part of it's
040 upgrades provided a dust filter to prevent this.  If your drive has
this problem it usually can be fixed simply by cleaning out dust from the
drive.  NeXT sold a cleaning kit for both the drives and the optical


Subject: L4. How many colors can NeXT machines display?

The monochrome machines can display 4 gray levels.  You can use color
apps on a monochrome machine,  they will converted into monochrome
images and dithered accordingly.

Color NeXTstations can combine 4 bits of red, green and blue primaries
for a total of 4096 "pure" colors.  The imaging functions dither the
image to produce intermediate colors.

NeXTdimension can combine 8 bits of red, green and blue for 16,777,216. 
There are not 16 million points on the display so all can not be displayed
at once.  Further display technology limits the usable color space.

None of the NeXT products support color look up tables where the user can
define their own color palette on a per window basis. This feature is
useful for displaying images which have adaptive lookup tables, and
display pure grayscale images on the color NeXTstation.  On the
NeXTdimension images can be converted to full 24 bit representation.      


Subject: L5. Why is my machine so slow when I run the monochrome and NeXTdimension displays?

There is a bug with the window system in which if you select the
monochrome display as your primary display the server will be much much
slower.  The solution for those wishing to use both displays is to select
the color (NeXTdimension) display as the primary display.  The most
optimal configuration at present with the NeXTdimension is to run only
the color display.   


Subject: L6. Where to obtain replacement mouse parts?

[[email protected]]

For those who have need of a new button in their mouse, and don't want to
pay for the whole mouse when it is only the button that has gone bad, we
have recently discovered a satisfactory replacement for the Omron
switch. It is in the Digikey catalog, # 931, Jan-Feb 1993, page 141,
under Cherry switches D4, DG, and DH series. Digikey part # CH164-ND,
Cherry part # DG1C-B1AA. We ordered one of these, and just received it
today. Tried it out, and it sems to be working flawlessly so far.     


Subject: L7. Where to obtain extra batteries?

Battery part number: BR 2/3A 3V Lithium Battery (Panasonic)

Source: Engineered Assemblies & Components Corporation

	5204 Green's Dairy Road
	Raleigh, NC 27604
	Phone: 919-790-9700  (ask for Debra)

	Price: $16.71 for 2 batteries incl. shipping & C.O.D.


Subject: L8. How to convert a Turbo system to use ADB?

[From: [email protected] (Brad Sime)]

If ADB equipment are used with older NeXT systems they won't work properly.  

Here are the ADB requiments:

	a) A Turbo computer.

	b) CPU eprom version 74.

	c) New revision computer to soundbox/monitor cable.  The part
	number is molded at both ends of the connector:

	Cable			NEW		OLD (Non ADB)

	NeXTcube		4534		150
	NeXTstation		4535		1532
	NeXTstation color 	4536		2286

  	d) New revision monitor which uses a vertical scan rate of 72hz
	instead of 68hz, except on NeXTdimension systems color monitor
	stays 68hz.  

	Monitor		NEW (72hz)	OLD (68hz)

	17" mono	ACX (N4000b)	AAA (N4000a & N4000)
	17" color	ADF (N4006)	ABG (N4001)
	21" color	ADB (N4005a)	ABH (N4005)

	e) ADB soundbox for color sytems.  S/N prefix ADD instead of ABN.


Subject: L9. How to put a 68030 board in the same NeXTcube as a 68040 board?

[[email protected]]

**********************   DISCLAIMER  DISCLAIMER   **************************
The following procedure is not supported by NeXT, Inc. and will  
definitely void the warranty on your NeXT computer.  Follow it at your
own risk.  I disclaim all responsibilities for damages caused by
negligence in following the procedure.  There is no guarantee that the
procedure will work on all versions(?) of the NeXT cube hardware.  All I
know is that it worked on the NeXT cube I was working on!!!!  SO BEWARE! 
**********************   DISCLAIMER  DISCLAIMER   **************************

Here we go!  I'll first provide a description of the hardware I was using
and comment on what I accomplished and how I got the information on how to
do it!

The hardware included a NeXT cube with 660 MB drive, OD, etc., a 68040  
upgrade board, and a 68030 motherboard.  I successfully installed both
the 68040 and 68030 boards on a SINGLE NeXT cube and linked them together
through their ethernet ports.  The 68040 was configured as a boot server
and the 68030 was used as its client (booting off the network for lack of
an additional hard drive).

The procedure reconfigures slot #2 on the cube's back-plane as slot #0. 
This provides two slots configured as #0, required for booting the two  
motherboards.  Once I determined what the slot pin-outs were (thanks to
my good friend John Chmielewski), it was a matter of time before the two
boards happily co-existed.  

The procedure:

1. First, follow the procedure on the NeXT User's Reference manual for  
removing the system board (Appendix C: Opening the Cube, page 291 of the
2.0 manual).

2. Using the NeXT supplied screwdriver, remove the two screws that  
attach the power-supply housing to the cube (the screws are located on
the lower part of the housing) and gently pull the housing out.  Set it
aside in a safe place (away from kids and nosey friends!)

3. Remove the two plastic grooved plates (used to slide the system  
boards in) at each side of the inside bottom of the cube.  (For each plate,  
lift the side closest to the rear opening and gently pull them out).  Set
them aside. 

4. Using the NeXT tool, remove three screws holding the back-plane to  
the cube and then take the back-plane out of the cube.  Let the cube rest
for a while. 

Inspect the back-plane.  You will see five bus slots (four vertical and  
one horizontal).  The horizontal slot connects the back-plane to the
power supply housing.  We're only interested in the four vertical
slots.  From the factory these slots are configured as 6, 2, 0, and 4
(starting from the left and going right with the horizontal slot at the
bottom).  The system board connects to slot #0 (which you've probably
noticed).  Each slot contains three columns of 32 pins.  Following is an
ASCII representation of one of the slots:  

			x y z	 C B A
			o-o o 32 . . .
			o-o o 31 . . .
			o-o o 30 . . .
			o-o o 29 . . .
			      28 . . .
			       3 . . .
			       2 . . .
			       1 . . .

...where x, y, and z are labeled GND, SID, and VCC, respectively.  The GND,
SID, and VCC "holes" are used to configure the slot number using simple  
binary encoding, where GND is logical zero, VCC is logical one, and SID
(for Slot-ID I guess) determines the current bit state (one or zero). 
Notice the four rows of GND, SID, VCC triads; each row is equivalent to
one bit position in the slot number, the bottom row bit position 0, the
top row bit position 3.  This gives a total of four bit positions, or 16
possible slot numbers.  To encode a slot number, you need to connect an
SID row to its corresponding GND or VCC row.  For example, the diagram
below shows the configuration of the slots in my cube's back-plane
(you'll have to look very closely to see the actual connections):  

		SLOT #6		SLOT #2		SLOT #0		SLOT #4
	BIT 3:	o-o o		o-o o		o-o o		o-o o
	BIT 2:	o o-o		o-o o		o-o o		o o-o
	BIT 1:	o o-o	      * o o-o *		o-o o		o-o o
	BIT 0:	o-o o		o-o o		o-o o		o-o o

... Now on with the procedure:

5. To reconfigure slot #2 as slot #0, cut the trace between SID and VCC for
bit position 1 (see * o o-o * above) and connect SID to GND on the same row.
I used the SIMM removal tool supplied by NeXT in the 040 upgrade (talk
about multi-purpose) to cut the trace!  Very gently, scrape the solder
off between the two holes.  Take a paperclip, shape it to fit between the
holes in SID and GND, and trim it down to an even 1/4 inch (perfect fit)!

That's all there is to it.  If for some reason you ever want to revert to
slot #2, just remove the paperclip from GND-SID and reconnect it to

6. Now put the cube back together.  First, re-install the back-plane  
using its three connecting screws, then snap on the plastic plates, and
finally insert the power-supply housing and secure with its two

At this point the cube is ready to take on the two system boards (it is up to
you to determine where/how you want to use the two boards; I'll explain
how I used mine) ... 

7. I installed the 68040 in the original slot #0 and the 68030 in the  
reconfigured slot #0 (previously slot #2).  The 68040 was used as the
main processor board.  I connected the 660 MB drive, the OD, and the
monitor to it.

NOTE: Before beginning the procedure, I went into the NeXT Monitor on
the 68030 and disabled the Sound out, SCSI tests and verbose test mode
and enabled serial port A as a console terminal.  I also made "en" the
default boot device. I setup the 68040 as a boot server and taught it
about the 68030 (which took some time in getting it setup properly). 

8. I connected the 68040 to the 68030 using a thin-ethernet cable and I  
booted.  First thing I noticed was that the 030 timed-out a couple of
times waiting for the 040 to tell it to boot.  But after the 040 was up,
the 030 booted nicely.  

That's all folks.  Hope all this made some sense and people find it  


-  To power off the cube, I have to first shutdown the 030 (I run "halt -p" as
root from a telnet connection and wait for the 030 to go down), and I then
power-down the 040.  If you shut down the 040 before the 030, you'll have
to pull the power plug to turn the machine off.  The cube will not power off
if either of the two boards is providing a load to the power-supply.

-  Remember, I've only performed this procedure on one system.  I do not
know what will happen on your system.  So make sure you plan ahead what  
your going to do and that you understand the procedure.

-  I don't know what problems may arise when you add a board that uses the
NeXTbus, such as the NeXTdimension, or how it will behave. If someone is  
courageous enough to perform the procedure and intalls another board,
please post your results to the net.

-  If you think this procedure has done any good for you, please feel free
to send in donations.  8^)  (think of it as "hardshare") 

________________________ UPDATE TO PREVIOUS ARTICLE __________________________

To clear up some misunderstandings with the settings in the "p"
command of the NeXT monitor (these settings are only required for the
system board that doesn't have the NeXT display monitor connected):

1. Sound out test must be "no"; the boot process will not proceed if the
monitor isn't connected to the board and this is set to "yes" (the sound  
out tests will fail, aborting the boot procedure).

2. SCSI tests should be "no" if you don't have SCSI devices attached to  
the board (SCSI tests will fail otherwise, aborting the boot

3. Verbose test mode must be "no" for booting from the network.  If set to
"yes", the boot process will timeout waiting for a BOOTP and you'll be
left in the monitor with no means of restarting the board (except
pulling the power plug)!  This is probably true also for booting from an
OD that hasn't been inserted (assuming the OD was attached to the

4. Allow serial port A as alternate console if you want to view the boot
process (for problems and peace-of-mind).

5. Other settings were not modified from their factory defaults or had  
no effect on the procedure. 


Subject: L10. How to expand DSP memory?

The Speech Recognition Lab at San Francisco State University has
developed a DSP memory expansion board for the NeXT computer that
provides the maximum memory supported by the DSP56001 processor. We are
now offering this board to those whose are interested in
high-performance custom DSP development.

-- The board is a 576KB DSP expansion memory board organized as three
non-overlapping 192KB banks: X-data, Y-data and Program.  The board
uses relatively fast (<35ns) SRAM.  This board compares with NeXT's DSP
memory expansion board, which offers only 96KB in an imaged memory

-- The board is a high-quality, 4-layer board, open-circuit tested
prior to assembly. It fits into the DSP memory daughterboard slot on
all NeXT machines.

-- The price will be $600. Please let us know if you are interested.
Delivery will be in about 3-4 weeks.

-- Contact Tom Holton ([email protected]). E-mail is prefered. The
address is:

	Tom Holton
	Division of Engineering
	San Francisco State University
	1600 Holloway Avenue
	San Francisco, CA 94132
	415 338 1529 (phone)
	415 338 0525 (fax)

Note: Because we've organized our memory as three separate
(non-overlapping) banks (X, Y and P) of 192KB apiece, none of the DSP
memory image functionality provided by NeXT with its existing 8K base
configuration, or its 96KB DSP expansion module is supported. While we
cannot guarantee that every existing DSP application ever written will
be plug-and-play compatable with our DSP expansion memory, we are not
aware of any existing applications that use the image functionality.
The MusicKit, and demo programs that use the DSP, such as Mandlebrot
and ScorePlayer, work fine with our memory module.


Subject: L11. How to boot a NeXT without a monitor?

[From: The Onyx Kitten <[email protected]>]

The procedure is to just touch pins 6 and GND on the DB-19 NeXT monitor out
with a 470 Ohm resistor (450 is the actual resistance, but 470 ohms is
more commonly found in resistors).  Pin 6 is the power sense, and pins
13-19 (and the DB shell) are the GND.  Just say "pin 19", it may be easier.  
There's a pinout diagram of the DB-19 in the NeXT Users Reference Manual.

If you have an old Cube, the power supply needs to have more power drawn
from it than an 030 (and 040?) board uses to stay on.  So:  On the DB-19,
attach a Power Resistor (20 Ohm, at least 20 Watt) between pins 12 and
GND. (Pin 12 is -12V, pin 13 works well for GND).  Then just "touch" the
470 ohm resistor as described above, and you're set.  The 20 Ohm resistor
draws an old 030 running monitorless in an old CUBE), but it isn't
necessary - just don't touch it  (*HOT!*  ;-)

To power off, type "halt -p" as root on the machine (either through a 
terminal connected to port A, or over the eithernet connection).

Also, you have to have the Rom Monitor settings done correctly.  The
important ones are:

Wait until keypress? N
Sound out tests? N
Port A as alternate Console? Y (if you have one, it's nice)
Verbose mode? N (I think this may need to be N to work, don't remember). 


Subject: L12. Two internal hard drives on NeXT Motorolla 68040 slabs?

[From: [email protected] (Todd Takken)]

It is possible to fit a second internal hard drive in
a NeXT slab, in addition to the floppy drive and the
first hard drive.  The second drive must be third
height, or 1 inch high.  There is no room for a half
height device.  Buy a bracket or make one out of sheet
metal for the 1 inch high drive.  On 25 MHz mono
stations the SIMMs are smaller and the drive doesn't
have to go all the way against the back wall.    In
this case, glue the bracket to the underside of the
NextStation cover, centered from side to side and as
far to the back as possible.  This is sufficient.  On
25 MHz colorstations, however, one must file away a
bit of the interior metal on the cover in order to
glue the bracket fully to the rear of the cover.  Once
this modification is done, the drive will clear the
RAM when the cover is closed.  Screw the drive into
the bracket, with the power and SCSI plugs toward the
right hand side of the NextStation so that the cables
will reach.  Go to your favorite computer store and
get both a "dual internal SCSI bus cable" and a "dual
internal SCSI power cable."  Plug in the cables to
both internal hard drives and close the cover.

This was verified on both a 25 MHz mono and a 25 MHz
color NextStation.  No power or heating problems


Editor: [email protected]
Nathan Janette
Systems Manager, Axel T. Br�nger Lab

Internet:	[email protected]