KM11 maintenance module

From: Tony Duell <>
Date: Tue Nov 23 23:14:11 2004

> I found a copy of the schematic in the RK11-C printset. Mr. Duell's
> description does an excellent job of updating it. What is the equivalent
> of the DEC3009 transistor?

I think just about any NPN transistor that would handle the lamp current
would worl.

A word of warning (discovered the hard way!). Some DEC machines put 1k
(or so) resistors in series with the input signals to the KM11. If you
use TTL buffers to drive the lamps (I tried 7406s), it won't work
properly -- they take too much input current. Also, some machines fed the
lamp off an unsmoothed supply, hence the capacitor between the '8V' line
and ground.

> True, but if you have the manual that describes how to use the KM11, you
> usually have an image of the overlay.

>From what I remember the PDP11/45 prints didn't include the overlay
patterns ;-(. I did trace out all the signals, I can provide a pattern if
you need it.

> It looks like the lamp board is a dual width, single height. It should

Both the boards were single height, extended length.

Received on Tue Nov 23 2004 - 23:14:11 GMT

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