Search Posts:

M7856 Setup

View Entire Thread

Return to Threads
SHARE
  by Bill Degnan - 03/18/2015 10:48
M7856 BERG Connector
Using guidance found in documentation and web resources I found the correct pin assignments for a serial console cable to connect from the M7856 to a serial terminal. Fortunately I had a BERG connector available. I set the jumpers to 9600 baud. Click image for larger view.


Null Modem adapter
Next I attached the EIN cable end to a null modem adapter and a longer straight-through cable. The end of the straight-through cable was attached to the COMM port of a VT 102 terminal set to 9600 baud.


PDP 11/40 with VT-102 terminal
This photo shows the PDP 11/40 with VT-102.


PDP 11 echo character program output
I toggled in a program that takes characters typed at the terminal, passes them through the PDP 11/40 and echoes them back to the terminal screen.


The progress thus far was short-lived. The system returned to an AC LO failure condition ((see thread))and the 5 amp fuse blew out. I have parts on order so I can make more permanent repairs. But at least I got a little taste of the machine. I should have waited until I finished the power supply repairs but I was impatient, can you blame me?

The RAM board was kind of flakey, I need to replace the caps on this card as well as the power supply control board's caps and resistors that have failed.

Reply

Resources:

  • Home
  • Manufacturer photos, software, docs
  • Disk Images
  • Computer History Articles Scans and Files
  • YouTube.com Videos
  • Sale/Trade/Wanted/Miscellaneous
  • Photo Gallery
  • The Ultimate Vinage Computing Links List
  • Switch to DOS Prompt view

    • Buy a Commodore Computer Poster

    Popular Topics and FAQs


  • Commodore B Series Tips and Tricks
  • Aerocomp TRS 80 M 1 Expansion Unit DDC
  • Items Wanted
  • Lobo Max 80
  • Zenith Z-19-CN
  • Prototype PET 2001 photo
  • Using Toggle Switches to Analyze Memory
  • Commodore Disk Archive Project
  • PET 2001 Prototype at Gametronics 1977
  • Jim Butterfield Photo
  • IMSAI 8080 With Processor Tech. Cutter
  • Secrecy is the keystone of all tyranny
  • Cromemco System Three
  • Northstar Horizon - Boot Problem
  • Computer History and Restoration Links
  • Commodore BX-256-80 - 8088 Co-processor
  • S-100 board testing with Z-80 ICE
  • Donner 3500 - an early portable computer
  • Digital (DEC) PDP 11/05 NC Assembly
  • Univac 1219 rescue
  • IMSAI 1.4 BASIC vs. MITS 8K BASIC
  • Fido BBS listing node list 6-13-1986
  • PDP 8e
  • MITS 88-2 SIO (2SIO) for BASIC
  • Visual Technology Inc Model 1050
  • Amiga 2500 Restoration
  • The Evolution Of IBM Computers
  • Replacement teletype print hammer head
  • Archiving and Copying Software 101
  • Computers Built 1940 - 1950
  • CBM B-520 (a.k.a B256-80 or B500 256)
  • RCA COSMAC Microkit
  • Commodore 64K C-116 Mods
  • MITS 8800b Turnmon 9600 baud
  • Catweasel, 8in and 5 1/4
  • Raspberry Pi as Gateway to Internet
  • Digital PDP11 late 1969 early 1970
  • PDP 11/40 72 inch cabinet model
  • PDP 11/40 Industrial 11 model
  • Digitial MicroVAX 3100 30 System
  • Digital VAX 4000-200
  • Commodore 64 / 1541 DRIVEKNOCK
  • Booting the System Using RL02 drive
  • PACS: Reflections by Kathleen Mauchly
  • Tele-Graphic Computer Systems Inc.
  • Commodore B Series SID Jukebox?
  • Installing Core into PDP 11/40
  • Setting Up OpenVMS 7.1 DNS CLERK
  • Felt-Tarrant Comptometer Model J
  • NextStation Color
  • Digital Rainbow (PC100-B2)
  • 1970 Compusad Compulogical Tutor
  • Archiving Papertapes Using DSI NC 2400
  • 1976 P.C.C. Features the MAI JOLT 6502
  • 1961 Beckman DEXTIR Computer
  • UNIVAC 1 and UNIVAC File Computer 1

    • Past Issues:

  • Vintage Computer Festival East 3.0 June 2006
  • Commodore B Series Prototypes July 2006
  • VOLSCAN - The first desktop computer with a GUI? Oct 2006
  • ROBOTS! - Will Robots Take Over? Nov 2006
  • Magnavox Mystery - a Computer, or? Jan 2007
  • The 1973 Williams Paddle Ball Arcade Computer Game Feb 2007
  • The Sperry UNIVAC 1219 Military Computer May 2007
  • VCF East 2007 - PET 30th Anniversary June/July 2007
  • The Electronic Brain August 2007
  • Community Memory and The People's Computer Company October 2007
  • Charles Babbage's Calculating Machine December 2007
  • Vintage Computing - A 1983 Perspective February 2008
  • Laptops and Portables May 2008
  • From Giant Brains to Hobby Computers - 1957 to 1977 August 2008
  • Historic Computer Magazines November 2008
  • World's Smallest Electronic Brain - Simon (1950) December 2008 - Feb 2009
  • Free Program Listings Spring 2009
  • Computer Music Summer 2009
  • Popular Electronics Jan/Feb 1975 - Altair 8800 Fall 2009
  • Early Microcomputer Mass Storage Summer 2010

    • tricord m4050c powerframe

    This image was selected at random from the archive. Click image for more photos and files from this set.