David Evans wrote: > > In article <329EEB2F.4955@austria.ds.philips.com>, > Stefan Holzinger wrote: > > > >Is it as simple as installing a switch turning off +12V and > >-12V for the CRT PCB or would this turn off the communication > >board, too - confusing the system? > >Is the power supply capable damping the switch on/off spikes > >or will it damage my system? > > > > A while ago it was decided that there's no reliable way to turn off the > monitor. The following was posted by me in June 1996. Yes, it *is* possible to run your Black hardware without a monitor. The trick is just to get the NeXT to power on, and boot correctly. This is a rewrite of an older FAQ item attributed to "The Onyx Kitten" who no longer is at this mail address. The only reason for redoing this is to make clearer what exactly needs doing and report my personal experiences in this process. My thanks to Justin Sowers for his insight and assistance. HARDWARE SETUP The task is to build a DB-19 male plug to replace the DB-19 cable coming from your Black monitor. You can also use the more common DB-25 male plug as a replacement, but you will need to crimp (or remove) the pins on the right-hand side of the DB-25 so they are not in the way. An easily obtainable parts list is as follows: Radio Shack SKU# Qty. Description Price (as of 03/96) ------------------------------------------------------------------ 275-1556 1 2 pack Push-button switches $1.99 271-1317 1 5 pack 470 Ohm, .25 Watt resistors 0.49 276-1549 1 Grey housing for DB-25 connector 1.19 276-1429 1 25 pin male D-sub connector 1.99 Total: $5.66 + tax If you are a stickler for exact parts then you can order DB-19 connectors from: Gateway Electronics of St. Louis, San Diego, and Denver 1-800-669-5810 314-427-6116 VOX 314-427-3147 FAX http://www.gatewayelex.com for $1.50/ea. (as of 3/96). Minimum order for mailing: $10. Many thanks to Carl Lowenstein for the pointer to this one. NeXT MegaPixel DB-19 female inside DB-25 male (Connector screwmounts shown for positioning) ________________________________________________ \ _ ................................. / _ \(_) : 10 9 8 7 6 5 4 3 2 1 :/ (_) \ : 19 18 17 16 15 14 13 12 11 :/ \ ............................./ ---------------------------------------- DB-19 Pinout: 1= +12 V 7= NC 2= -12 V 8= VSYNC 3= MON CLK 9= HSYNC 4= MON DATA OUT 10= VIDEO 5= MON DATA IN 11= +12V 6= MON PWR SWITCH 12= -12V 13-19= GND THE DONGLE Build the following simple circuit with a momentary push button soldered to the 470 ohm resistor. This assembly should then be wired across pins 6 and 19 of the DB-25 shell. If you have an older cube (030 motherboard) then you will need to be sure that the box draws more power than just for the motherboard in order for the machine to stay on. This can happen in ONE of two ways- 1) You have a disk drive, or other power-drawing internal peripheral connected and in use (not that uncommon), -or- 2) You connect a POWER resistor (20 Ohm, at least 20 Watt) across pins 12 and 13 (as labeled for the DB-19 diagram). I do not recommend the power resitor approach, as the resistor gets _very_ hot and remains an active circuit for the time the machine is on. NeXTStation and 040 cube owners do not have to worry about the idiosyncrasies of the older NeXT power supplies. Here's the circuit: \ Momentary push __ \__ | | | | 470 Ohm $ | | | | | v v To DB-25 pins: 6 19 The soldering involved (resistor to switch terminal & connector pin, and wire to switch terminal & connector pin) takes maybe 10 minutes and is not very technical as the pins are individual so you can attach them to your assembly before you put them into the plastic framework the holds them together as a DB-25 (if you are using the RadioShack parts list above). The power resistor mentioned in the FAQ turns out to be unnecessary if you have anything else in the cube that draws power (a disk, etc.). All of this fits nicely into a plastic DB-25 housing with the pushbutton sticking out where the cable would normally exit. NeXT Cube owners will need to shave down the left (as drawn in illustration) side of the housing inorder to get the "dongle" to fit (the monitor port is at the very bottom of the motherboard and doesn't afford much clearance past the securing screwmount). SOFTWARE SETUP You'll need to be sure your NeXT ROM Monitor settings are correct and that your O/S is ready to run without a monitor. To start, go into the NeXT ROM Monitor (press Command-Command-~) and set the current configuration settings (from "p" in the boot monitor) like this: boot command: whatever DRAM tests: yes perform power-on system test: yes sound out tests: no SCSI tests: no loop until keypress: no verbose test mode: no boot extended diagnostics: no serial port A is alternate console: yes <- recommentation allow any ROM command even if password protected: whatever allow boot from any device even if password protected: whatever allow optical drive #0 eject even if password protected: whatever A few people report they needed to do nothing more on a Cube (level of OS unknown). In my experience on a NeXTstation (NS 3.2), it was necessary to make these changes in /etc/ttys: console "/usr/etc/getty std.9600" NeXT on secure #console /usr/lib/NextStep/loginwindow NeXT on secure window=/usr/lib/NextStep/WindowServer onoption="/usr/etc/getty std.9600" ttya "/usr/etc/getty std.9600" unknown on secure ttyb "/usr/etc/getty std.9600" unknown on secure A WORD TO THE WISE I would recommend that before you do anything, you make sure you get serial port A working as an alternate console. You can do this with a simple null-modem serial cable connection to a DOS machine running kermit (or other simple-minded terminal emulator). If your black box gets a kernel panic (like mine) and you have disabled the console in /etc/ttys, you might be left in a state where you must re-install to get your machine back up. It seems prudent to always have a serial console solution in case something serious happens and you need to be able to see what is going on. Don't forget that you should remove any printer that is configured for serial port A if you are also using serial port A as an alternate console or serial tty. BOOTING WITHOUT A MONITOR Once the DB plug is built, the ROM Monitor settings are correct, your serial A port console works, and /etc/ttys is correct, then simply power down the NeXT, remove the DB-19 monitor cable, attach your new DB plug and press the momentary switch/button. The box should power on and go through its normal boot sequence. You'll see ROM Monitor messages on the console on serial port A (you are using one, aren't you?). CAVEAT EMPTOR I've tried to be very careful about these instructions, but maybe I missed something, or maybe your situation is somehow different from mine. I might be able to say something that will be helpful, but maybe not. All in all, you are on your own, so be careful. In any case I am not responsible for what you do to your own hardware. -- =================================================================== Terry Gliedt tpg@fv.com MIME OK First Virtual Holdings http://www.fv.com/ http://www.hps.com/~tpg/