computerhistory

Elektronika BK-0011

Spurtikus
Elektronika BK0011 is successor of BK0010, same in english. Both use PDP clone-like CPU K1801WM1. The CPU is said to be fully compatible with PDP11 CPUs, but does not implement EIS instructions. See articles in OldComputerMuseum, PDP11 Instruction set CPU runs at 4Mhz. BK0011 has 128KB RAM. Monochrome/Color output via DIN connector. Built-In speaker and (russian) keyboard. Parallel and serial ports. QBUS available at back side of case. Slots for inserting additional option ROMs

Checking a defective memory module with QBone

Spurtikus
This post describe my effort to fix a broken M8044 PDP11 RAM module. For tracing down the bug, I’ve used QBone. I own a defective M8044 RAM board. This board came as part of my OBA-11 PDP11. It was obviously checked by DEC, found to be broken and has a red defective badge. Setting up test bed I’ve created a testbed, consisting of: QBone An unused backplane H9278-A with 8 slots The device under test, the M8044 As power supply, I took a 5V/4Ampere power supply from my parts bin +12V (used by M8044) supply comes from a lab power supply First test with QBone: Check if board responses to bus requests QBone has its tests and many features in a single executable.

QBone

Spurtikus
What is QBone? QBone is a fascinating project by Jörg Hoppe. It is based on a PDP QBus module that can be inserted into any QBus backplane. It implements all features required by the QBus, so this module looks like any other QBus module from the PDP11 perspective. The module integrates a BeagleBone Board (BBB). This is an ARM-based modern computer, like Raspberry PI. The biggest advantage of BBB over Raspi is: that the board contains two separate I/O processors called PRU (Programmable Realtime Unit).

DEC VAX 4000 Boards

Spurtikus
My DEC VAX 4000 boards All boards seem to come from a VAX 4000-300 machine. See http://gunkies.org/wiki/VAX_4000_series ebay seller text DEC VAX 4000-300 Boards CPU KA670 L4000 in Module Plastic Case (99-08536) 2x MS670-CA L4001-CA und 1x64MB Clearpoint Memory KA670 CPU board 22 Bit QBus board. CPU clocked with 143 Mhz. CPU chip is called REX-520 There is a FPU on board called CD523. Built-in Ethernet and 2xDSSI (disk) controllers

DEC PDP11 Rebuild

Spurtikus
This document contains information I have gathered when trying to bring some DEC PDP11 boards together to have a “working” system. Summary of boards I have collected some boards in the last years. CPU boards: M8186 LSI-11/23 CPU (C Revision, so capable of 22 bit addressing) RAM boards: M8044 MSV11-DD 32K RAM, 18Bit M8067 512KB RAM, 22 Bit Serial boards: M8028 DLV-11F serial board M3104 serial board Multi Purpose Boards:

DEC Digital OBA11-MF

Spurtikus
DEC Digital OBA11-MF bought in poor condition from ebay. It has no case, has some physical damage. Sold of course as defective. All together this seems to be a kind of “embedded” PDP 11/03 with only a bare minimum of boards and no intention for extending it later on. Maybe used as a control unit in some chemical plant or whatever. here someone has a picture of another device like this.

PDP 11 parts

Spurtikus
I own some old PDP11 parts. I try to complete these to have a minimal set of cards to boot the PDP11. This is seen as a long term task and may last several years… Activity was started in February 2017. In January 2021, I have spent 91+161+3*90 = 522€ on that madness, without any results so far :-) . In 2022, I could buy a basic PDP unit, without case and in bad condition.

Converting a DEC Keyboard LK401 to an USB Keyboard

Spurtikus
DEC Keyboard LK401 has serial interface, 4800 Baud, 8N1. See more information on the keyboard hardware here. The keyboard is solid and heavy, has superb tactile keys and is of the old 80ies quality. That you simply cannot order on Amazon or so. For a long time, the keyboard was supported by the Linux kernel, but this time is gone. My idea: connect the keyboard to a microcontroller that can connect to a PC via USB.

DEC LK401 Keyboard

Spurtikus
This keyboard came in as part of a Digital DEV VT402 terminal. I have some information on that terminal here . After some time, I found that the keyboard of that terminal is also an interesting kind of thing. DEC LK401 Hardware DEC Keyboard has a serial interface. The connector to plug into a DEC VT420 terminal looks like an old telephone connector, with 4 pins, called RJ10. An Intel 80C51 microcontroller handles most of the keyboard functions We can see also the Beeper and a 7.

Digital DEC VT420 Terminal

Spurtikus
Some pictures from inside a DEC VT420 from 1994. Wikipedia has some info on it here It is a 14'' device with 800x400 pixel, can handle up to 38.400 Baud. (click to view larger version) Monochrome tube with HV transformer. (click to view larger version) Closer look on main pcb. Below the shielded area I suspect the digital part of the device. (click to view larger version) Again HV section