Image Map Image Map
Results 1 to 3 of 3

Thread: DEC Professional 350 - video issues

  1. #1

    Default DEC Professional 350 - video issues

    I went out to visit a guy who posted a moving-sale giveaway on cctech this weekend and came away with a few DEC goodies, including a DEC Professional 350 which was given to me on the understanding that the video didn't work. I set it up this afternoon and sure enough, the video doesn't work. Specifically, the monitor turns on and displays no picture, but shows visible sync lines all across and down the screen, and the diagnostic LEDs indicate a selftest failure on the card slot that the bitmap card is plugged into.

    (I tried moving it to another slot just to check, and sure enough, it fails there, too. I don't think it's a general CTI bus issue because the other two cards don't generate a selftest failure code. I do need to test the monitor with the Rainbow I also picked up to make sure that it's good, but with the card itself generating an error, I suspect that's not the issue here.)

    The card itself doesn't have any socketed ICs, so it's not chip creep, and the ZIF connector looks to be in good shape. Beyond that, I don't know what to look for in diagnosing the issue - do any of our resident DEC nuts have any idea what might be wrong with it, and how it could be fixed?
    Computers: Amiga 1200, DEC VAXStation 4000/60, DEC MicroPDP-11/73
    Synthesizers: Roland JX-10/SH-09/MT-32/D-50, Yamaha DX7-II/V50/TX7/TG33/FB-01, Korg MS-20 Mini/ARP Odyssey/DW-8000/X5DR, Ensoniq SQ-80, E-mu Proteus/2, Moog Satellite, Oberheim SEM
    "'Legacy code' often differs from its suggested alternative by actually working and scaling." - Bjarne Stroustrup

  2. #2

    Default

    John - Be sure to check which video cable you are using. For the color board and VR241 color monitor there are unique versions for the PRO vs Rainbow and you need the correct one for each chassis. The Rainbow uses a BCC17 cable with the VR241 color monitor, and the PRO needs the BCC03 cable. I believe for monochrome you can use the BCC02 cable and VR201 monitor for both Rainbow and PRO. Good Luck!

  3. #3

    Default

    Quote Originally Posted by commodorejohn View Post
    I went out to visit a guy who posted a moving-sale giveaway on cctech this weekend and came away with a few DEC goodies, including a DEC Professional 350 which was given to me on the understanding that the video didn't work. I set it up this afternoon and sure enough, the video doesn't work. Specifically, the monitor turns on and displays no picture, but shows visible sync lines all across and down the screen, and the diagnostic LEDs indicate a selftest failure on the card slot that the bitmap card is plugged into.

    (I tried moving it to another slot just to check, and sure enough, it fails there, too. I don't think it's a general CTI bus issue because the other two cards don't generate a selftest failure code. I do need to test the monitor with the Rainbow I also picked up to make sure that it's good, but with the card itself generating an error, I suspect that's not the issue here.)

    The card itself doesn't have any socketed ICs, so it's not chip creep, and the ZIF connector looks to be in good shape. Beyond that, I don't know what to look for in diagnosing the issue - do any of our resident DEC nuts have any idea what might be wrong with it, and how it could be fixed?
    It's not a slot error for sure. As you can see a sync lines on the monitor this means that this part of the card is working. It could be a memory chip failure.
    Back in 80's I was working in Russia on the institute that cloned this computers. We used to use a serial port cable to connect DEC Pro to a VT100 terminal and by shortening a RX line to ground were able to get a console command prompt on VT100. Then everything was like on any other PDP. If you get get this, you can test Video memory.

    I found link to a Russian hobbyist site with documentation to Dec Pro 350 clone Electronika MC 0585. You might find my name in there

    http://www.tis.kz/forum/topic.php?forum=31&topic=3

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •