SOLVED : How to boot a non-ADB NeXTstation with no keyboard?

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Title: SOLVED : How to boot a non-ADB NeXTstation with no keyboard?
Post by: fstark on September 09, 2020, 06:07:50 PM
Hi,

I have an original non-ADB NeXTstation with no keyboard/mouse attached. Is there a way to force it to boot even if there is no keyboard attached? (I'd like to check if the machine/monitor is working, I have a keyboard on the way, but it'll take a long time to reach me)

SOLUTION (thanks to all):

As suggested, briefly connecting a 550 ohm resistor between pin 6 and 19 of the DB-19 connector booted the machine.

After the slab had booted, I attached the monitor, which came to life too and displayed the ROM monitor.

(Station didn't really booted because I think the drive is dead, but that's another problem)
Title: Re: How to boot a non-ADB NeXTstation with no keyboard?
Post by: codepoet80 on September 10, 2020, 06:56:59 AM
Yes, I read somewhere that you can jump the right amount of voltage to stimulate a boot, but even after re-capping more than a dozen classic computers, I didn't feel comfortable trying it.

Recommend you load up a VM or Emulator to keep yourself busy until the keyboard arrives. Perhaps you can experiment with networking, or something, to get you warmed up.
Title: Re: How to boot a non-ADB NeXTstation with no keyboard?
Post by: rbz on September 10, 2020, 11:55:41 AM
I am not sure how you can test the monitor and computer combo together without a keyboard, but you can definitely at least see if the NeXTstation powers up by using a resistor to simulate the power button on the DB19 connector on the NeXTstation itself. The link below describes the procedure of using a resistor to simulate the power button signal. Remember it only takes a momentary touch to the right pins to start it, don't leave the resistor in place.

https://www.netbsd.org/ports/next68k/faq.html#no-monitor

I used this method to test my NeXTstations prior to having a monitor/keyboard/mouse to ensure they at least powered up since they were both purchased as "parts only, cant start" machines.
Title: Re: How to boot a non-ADB NeXTstation with no keyboard?
Post by: fstark on September 11, 2020, 05:50:02 PM
Thanks for the tip, rbz. I'll try it. I wonder if this would work on the keyboard pins (ie: a resistor between pin 4 and 5 of of https://www.drak.org/proj/next-keyboard-protocol/ ). Mmm. Maybe I'll wait until I get my keyboard to see if pushing the power button does close this circuit.


codepoet80, I don't think I need to get too warmed up, I used NeXT for development for many many years, between NeXTstep 2.0 in 1990 to the YellowBox on WindowsNT in the early 2000s. I painfully remember the various netinfo struggles, and I'm not looking forward to it that much :-)


That said, as I have no idea what is in the machine, I may have to try to partition and build a bootable disk by myself if the scsi is dead. Or can one get a real NeXT bootp from an emulated one? That could be fun :-)

Anyway, thx!

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