KM11 maintenance module

[Tony Duell]

> 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. 

-tony