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  1. BitWiz

    H758-a Schematic

    I have just acquired a DEC H758-a power supply. The plus and minus 15VDC supplies seem to be fine but the +5VDC supply is not working (0.2VDC). Does anyone have a schematic of this supply? I couldn't find it with a google search. Also, what is the best way to clean it. The inside is filthy...
  2. BitWiz

    Midwest Teletypes for sale - Redux with google drive pics and contact info.

    Hey folks. I need to re-home a bunch of cool old Teletype Corporation machines. Working condition unknown, and also have some spare parts. I am not out to make a mint, so make offer! They seem mostly complete, in varying condition. Some are nicer than others. They all worked when stored (years...
  3. BitWiz

    Midwest Teletypes for sale

    Hey folks. I need to re-home a bunch of cool old Teletype Corporation machines. Working condition unknown, and also have some spare parts. I am not out to make a mint, so make offer! They seem mostly complete, in varying condition. Some are nicer than others. They all worked when stored (years...
  4. BitWiz

    Hardware Plea

    I know that that it is highly unlikely but i will try anyway. Does anyone have a spare working RK8E or Plessey PMDC/8 RK05 Controller board set that might be looking for a good home at a reasonable price? Pretty Please 😊! I have two Plessey PMDC/8's and neither of them work very well. One...
  5. BitWiz

    OS/8 Driver Questions and an OS/8 Peculiarity

    I am writing down these questions as I read Doug Ingram's OS/8 device driver reference tome (deep respect intended). Doug - Thank you for this very informative and useful document. I plan on preserving it for future reference. If the data field is set to the current data field before the call...
  6. BitWiz

    SerialDisk Fun and a question.

    I've been having some fun with my Serial Disk Raspberry Pi. I modified the software to use 3 GPIOs for an RGB LED. Here is a video of my Serial Disk Tardis with LEDs. Blue = Waiting for Commands (2Hz, 50% duty cycle) Green = Sending data to the PDP-8 Red = Receiving data from the PDP-8...
  7. BitWiz

    DEC RX02 Diskettes

    I have about 2 dozen DEC RX02 8" Diskettes. These are the DEC branded floppies. Almost all of them have 1 or more bad sectors (determined by using the /R option of RXCOPY after formatting with the /D option). I have tried bulk erasing them, track erasing them in a greaseweazle, force...
  8. BitWiz

    OS/8 Questions (with a couple of SerialDisk questions thrown in.

    Now that I am up and running I have the following questions: 1. Where can I get a copy of the OS/8 TTY driver that supports lower case? 2. When using my terminal emulator how can I get OS/8 to recognize backspace instead of rubout? 3. The HELP command output screen control codes but when...
  9. BitWiz

    "DECnut" pizza dinner at VCF Midwest Fair

    It occurred to me to get the "DECnuts" and friends together for pizza at my house. I live about 7 miles from the Hotel and I have a decent size basement and a fridge full of beer. Let's try to meet here between 7 and 8pm on Saturday night with pizza to be delivered sometime after that. My...
  10. BitWiz

    OS/8 Build Question

    With help from Vince (thank you) I was able to build RX02SY.PA and build a bootable OS/8 RX02 diskette. I copied all of the .SV, files including CCL.SV, over to the newly bootable floppy and when I try to run a command OS/8 says NO CCL. But CCL.SV exists on the floppy. If I boot from my...
  11. BitWiz

    Midwest I am looking for the Popular Electronics Digital Logic Micro Lab ( SWTPC Logic Demon)

    This was the kit that matched the article in April 1970 Issue of Popular Electronics. Yes I can build one from modern parts but I used one of these in 1972 and I would love to get my hands on one, at a reasonable price. Here is a link to the article...
  12. BitWiz

    Good inventory program to keep track of my DEC parts and stuff

    I'm looking for a good inventory program to help me keep track of all of my PDP-8 stuff. I would like to keep track of physical location, board etch revision, board modification revision, bus type, where used, etc. If you have any good ideas, please let me know. I'm using a simple spreadsheet...
  13. BitWiz

    KK8-E and KE8-E compatibility list

    I have acquired a fair number of CPU boards, some in sets, some separately and I'm trying to come up with a set that works. Is there a compatibility list of what revisions of boards (and modifications) are compatible. For instance will a M8300A/Rev B work with a M8330E/Rev C. The letter...
  14. BitWiz

    Building a bootable RX02 disk from SerialDisk

    Please forgive me for the length of this message. I am trying to include all of the pertinent information. I am trying to build an RX02 Bootable disk from the standard SerialDisk boot setup. The RX02 drives are connected to the computer and I has OS/8 V3T booting from SerialDisk with RXA0 and...
  15. BitWiz

    Dumb OS/8 question

    I haven't used OS/8 in depth in almost 50 years. My memory is a little foggy, so please forgive the dumb question. I have done the following: .R RXCOPY *RXA1:/D...
  16. BitWiz

    PDP-8 MAINDEC DIRXBD question

    What is the proper way to answer this question when prompted on the console: .RUN SDA1 DIRXBD.SV...
  17. BitWiz

    SIMH fails to build

    Trying to build the latest SIMH from: git clone https://github.com/simh/simh with the following build command in the SIMH directory: make BIN/simh Causes a bunch of compiler warnings which then causes the build to fail. Building on Raspberry Pi OS: Linux raspberrypi 6.1.21-v7+ #1642 SMP...
  18. BitWiz

    Serial Disk Questions

    I want to make a version of Serial Disk that supports RX01 & RX02 floppies. Is all I need to do is add the appropriate Load and Install commands in the runbuild script? I see RX02.BX, RXSY1.SY and RXSY2.SY on the default Serial Disk SYS: drive. I'm a bit confused because the OS/8 Device...
  19. BitWiz

    MAINDEC-8E questions

    My 8/E is up and running again (and booting into OS/8 via SerialDisk). I noticed that maindec-8e-d0ab (instruction test #1) has been replaced by maindec-8e-dhkaf-a. I can't find any documentation on this newer 8/E instruction test except the TIF of the first page. Does anyone know where I can...
  20. BitWiz

    Paper Tape Reader Needed for Archiving

    I have just acquired a number of PDP-8 paper tapes. My reader/punch is not working at the moment (neither is my PDP-8 but that's another story). I am looking to beg, borrow or buy a paper tape reader or reader/punch (stand alone or PC04) so that I can archive these tapes as they are getting...
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