Trying to get running an LSI 11/23

From: Tom Peters <>
Date: Mon Dec 27 23:25:52 2004

Q-Bus? Doesn't necessarily have a -12v. Mine didn't. The
bootstrap/terminator card had bipolar PROMs on it with a little charge pump
chip to supply the -12 for the PROMs. But the chip wouldn't supply -12v
soon enough after power up, so the system would drop to an _at_ debugger
prompt instead of booting. It's been about 20 years since I booted that
machine and I can still tell you how to boot it from the _at_ prompt: 173000G

I actually had to dig a 12v transformer out of my junkbox and wirewrap it
to the backplane to solve that problem, along with a bridge and capacitor
of course, to supply more timely -12v.

Al, are you listening? I think it was Senzig that wired that charge pump
chip to the board-- it was upside down, done dead bug style. Or maybe Dick

At 08:40 PM 12/27/2004 -0800, you wrote:

>I've been tinkering with this mutt LSI 11/23 system I've got and am trying
>to get it running. It's a custom-built system that has a mix of DEC and
>third-party boards. It's configured as follows--my apologies if I'm not
>conforming to standard DEC notation here [notes in brackets]:
>Cage 1
>Slot 1: DEC M8186 | CAMINTONN 504 [1]
>Slot 2: Dataram Diceon [2]
>Slot 3: Data Systems Design A4432-4 | Grant Continuity [3]
>Slot 4: Emulex TU0110401 [4]
>Cage 2
>Slot 1: Emulex Tu1110406 [5]
>Slot 2: Grant Continuity | Digital Pathways TCU-50DYR [6]
>Slot 3: MDB DLV-11J | DEC M9400 [7]
>Slot 4: Empty [8]
>1. I believe the Camintonn card is memory
>2. This has "RK:" written on the RK05 disk controller?
>3. The Data Systems Design card has "DY:" written on the handle.
>4. Tape controller; is connected by 25-conductor ribbon cable to adjoining
>Emulex card.
>5. See note 4.
>6. A real-time clock
>7. The M9400 has "HB BOOT" written on the board. Is this the boot ROM
>8. Does there need to be a bus terminator here?
>The DLV-11J is a 4-port serial card. Thanks to those who provided the
>documentation to get it wired. I think I have it correct. I've jumpered
>pin 3 to the RxD line and Pin 8 to the TxD line on my RS232 port. I've
>also jumpered pin 4 to ground as directed.
>The system powers up. There are +5V and +12V LEDs on the front of the
>panel that come on, and I've checked these lines at the power supply and
>they are good. One oddity: the terminal marked -12V is a perfect -0.00 on
>my volt meter. WTF?
>Anyway, how can I tell if anything is happening inside this thing? I can
>hit the BOOT switch and the RUN light goes on. There's a RUN switch with
>a momentary HALT position and an ENABLE position. I can hit the HALT
>switch and the RUN light goes off. I put the switch back in the ENABLE
>position and then hit the BOOT switch and the RUN light goes back on.
>I see nothing on my terminal (a PC running Procomm Plus in DOS so I have
>real serial ports instead of the bullshit that Win98 tries to pawn off as
>serial ports).
>I eventually want to boot RT-11 off floppies on this system. I guess I'll
>need a disk controller at some point.
>I'm completely lame. This is the first DEC system I've seriously tried to
>get running so I'm starting from -1 here.
>Any ideas?
>Sellam Ismail Vintage Computer Festival
>International Man of Intrigue and Danger
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Received on Mon Dec 27 2004 - 23:25:52 GMT

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