Problems with my PDP 11/24 (was:Question about memory boards used on VAX 11/7xx)

From: Pierre Gebhardt <>
Date: Wed Dec 29 01:56:30 2004

> > That's the info I found on the net from a 11/750 FAQ:
> >
> > "National Semiconductor Memory Systems: 1Mb memory boards. These
> > boards have PWB 551109464-002 B
> > PWA 980109464-001 D
> > etched on them. They have a push-button switch for disabling the
> > board, and a spare memory chip in a socket on the board. Board has
> > green and yellow LEDS, which should normally both be on. Disabling
> > the board causes the yellow LED to go out, and the red LED on the
> > L0016 to come on, indicating bad memory configuration."
> Those almost certainly aren't UNIBUS memory boards, but are
> 11/750-specific boards.

Thanks for this information, Patrick.
I guess, I'll have to wait for such a VAX, I haven't one yet ;-)

Currently, I'm setting up my 11/24.
It comes with an RL02.
Yesterday, I worked on it a bit, checking grant and bus continuity, everything's fine now.
I found out the bootstrap adress for the RL02 (BOOT Proms are located on the Unibus Map Module (KT24)) and gave it a try,
with the RL02 disconnected.
No problems with typing in digits with the VT420 terminal.

This morning, the 11/24 apparently don't accepts commands from the terminal, why ?

On the CPU-Board, the CLK-LED is always illuminated, even when I press the Boot-button. Then, the RUN - und the PROC-LED
turns on for a moment, that's all.

Yesterday, when I typed in the bootstrap adress of the diagnostics-PROM, the 1 - LED turned on.
The 0 - LED always remained off.

Today, no typing in is possible.

When I press the boot-button, I obtain something like _at_000002

I need to know the meanings of the LEDs on the CPU-Board.
Can anyone give me some help ?
In the Maintenance-Card, the functions of the LEDs are described but it doesn't appear to be on the net somewhere...

Thanks alot in advance !



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Received on Wed Dec 29 2004 - 01:56:30 GMT

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