PDP-10 KI10 panel - assembling BlinkenBone electronics

Parent Category: Stories Category: The PDP-10 KI10 console panel Written by Administrator

KI10 and BlinkenBone

A lot of electronic is needed to make the KI10 a full BlinkenBone device (see here for the different components).

When counting the various inputs and outputs of the KI10 panel, I found that I was extremly lucky: I could control everything on the panel with 3 BlinkenBoards, and over 95% of their inputs and outputs were in use. The early decision to drive 40 inputs and 88 outputs with one BlinkenBoard proved to be almost prophetic.

The whole electronic consists of

  • one PC power supply
  • one BeagleBone
  • one BlinkenCape
  • three BlinkenBoards
  • one special microcontroller assembly for all the queer analog controls on the upper panel (see next page)
  • lots, lots, lots of wires

To find a mechanical concept, all these components were reordered again and again. Suddently this pattern appeared and was fixed:

PDP-10 KI10 panel, BlinkenBone electronics layout

A single U-shaped metal plate was screwed against the backside of the KI10. Its lower segment provides a solid stand and holds the BlinkenCape with BlinkenBone, the middle segment is mounting platform for power supply and BlinkenBoards, the upper segment is used for fixing all the cables.

All lamps and LEDs are connected to a common supply voltage rails. The individual wires are switched to Ground with ULN2803 low-side drivers on the BlinkenBoards. So +12V and +5V are routed from the PC power supply to the "Lamp&Button" boards, and all BlinkenBoards have the same input/output drivers, whether they drive +5V LEDs or +12V light bulbs. The LED resistors were made pluggable, each one on it's own little PCB.

PDP-10 KI10 panel, BlinkenBone LED resistor pack

Making net lists

First I had to made detailed wire lists: which lamp is accessible over which connector? The DEC documentation was no help. I put labels and pin-counting rulers onto the DEC connectors and stressed my circuit tester:

PDP-10 KI10 panel, connector research

Beeeeep!

The netlist is now part of the Blinkenlight configuration file, see attachement below.

Plugging and Crimping

Since the pure amount of wires could have killed me, I had to find a wiring technology with minimal work load. Crucial where these ideas:

  1. A friend made "FlipChip-to-pin-header" adapters for me. So I could connect plain flat cables directly to the ancient DEC connectors on the "Lamp&Button" boards.
  2. I crimped connectors to the other end of the flat cables. So the cables can be plugged onto the pin headers on the BlinkenBoards, which in turn are directly connected to the output /input drivers.
  3. To order all the resulting flat cable stripes, a horizontal plate serves as platform for cables and cable tiers ... like a cable channel. The need to order all the cables scales up exponentially with wire count!
DEC FlipChip adapters to flat cable BlinkenBone connection tools: flat cable stripper and connector crimper
DEC FlipChip adapters to flat cable

 Crimp whenever possible!

The whole connection matrix is contained only in a big cable tree, no connection logic is put onto the BlinkenBoards.  And very less soldering is needed. It was the first time I used crimp connectors, and it was all fun. I like to work totally "cold" (no soldering), and testing individual connections is much easier compared to have a big bulk of wire-wrap on the BlinkenBoard patch field. And as I blew one register IC (there's so much +12V around), I easily could swap-in a new BlinkenBoard as replacement.

PDP-10 KI10 BlinkenBone wiring

Here working in the museum of my computer club: Crimping is fun!

Cable patterns

It was also fun ordering the cable into nice patterns:

PDP-10 KI10 BlinkenBone wiringPDP-10 KI10 BlinkenBone wiring
PDP-10 KI10 BlinkenBone wiring

This looks much better than my first BlinkenBoard project

 

The whole project needed 10 weeks, every free hour went into it. I was ready with wiring just in time: the last crimp contact was set on January 1st 2013, exactly 0:05 ... just when outside the firework started!

PDP-10 KI10 BlinkenBone complete

 

 

 

 

Attachments:
Download this file (pdp10-ki10.conf)pdp10-ki10.conf[PDP-10 KI10 panel - BlinkenBone configuration file for decoding wires to controls]57 kB