Search Posts:

Examine using Front Panel - problem

SHARE

Return to Threads

  Examine using Front Panel - problem by Bill Degnan - 09/06/2009 20:01
This is a note to self. I have an Altair mentioned elsewhere on this web site, SN 220744K, and the front panel has been mod-ed to with both IMSAI and Altair front panel connectors so either CPU interface card can be used.

When the Altair card in installed, examine does not work. Here is a substitute for examine in the mean time

assume you're starting from 000 000 but you want to examine what's in c000.

deposit load the following:
000 303 jmp [a7, a6, a1, a0 up]
000 000 lower [all down]
000 300 upper [ a7, a6 up] = c000
reset
put all toggles down
single step = watch for a15, a14 up = c000
now that you have jumped to c000, you can use the examine next.

NEXT:
try system with imsai CPU card, see if examine works. If yes, then it's the cable, if no, then it's the front panel (someplace).

See also post about the power supply capacitor for this system, needs replacing.

Reply
  Examine using Front Panel - correction by Daniel Roganti - 09/25/2009 08:03
Correction,

I actually made an adapter cable to allow use of either an Altair cpu card or Imsai cpu card. This isn't mounted inside the Altair, just a loose cable which you can move from machine to machine. I have it here at home to fix your other Altair :)

I can make another one to let you try it too.

The next time I visit we can look at that particular Altair again to see wht the Examine function quit working. I'm hoping it's a loose connection, if not maybe another chip went bad. I'll bring some more just in case.

=Dan Roganti

Reply

Resources:


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:


    hard disk III

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