I own an Acorn RiscPC 600 which I picked up from Ebay years ago which apparently works but did not come with a monitor. I purchased a VGA to DVI connector to hook up the computer to my PC desktop monitor but sadly it appears that the RiscPC won't sync with the monitor.

I did read that the video sync settings can be changed on the Acorn but as I am not able to raise an image on the LCD monitor, I am kind of in a Catch-22 situation.

Does anyone have any suggestions on how I can restore video to this fascinating retro computer?


1 Answer 1


The RiscPC was Acorn's first to use a separate RAM bank for the video.

It was intended that the video drivers would auto-synch to the monitor. However, there was often a failure to synch, leaving a blank screen. From your description, this is what you are experiencing.

I would suggest turning off the auto-synch. This can be done with the screen blank if you type carefully.

Power the RiscPC on and let it enough time to come up to the command prompt.
Type the following three commands:

*Configure Monitortype 4
*Configure Sync 0
*Configure Mode 40

This should reset the CMOS video settings to a basic VGA mode and give you a visible image on your monitor.

If that doesn't work, come back to us. I may have another suggestion if I can dig my old manuals out the attic.

  • The thought of typing commands with the screen blank brings back some fond memories of last-ditch repair scenarios! Good luck, @lian!
    – jpaugh
    Commented Jun 21, 2016 at 15:12
  • Thanks for the suggestion, but I'm afraid the monitor is style not picking up a signal from the RISC PC. It may be some issue with the DVI to VGA converter I bought, or something with the PC or the monitor. I'm afraid I may just have to move it on.
    – Iian
    Commented Jan 30, 2019 at 2:15
  • 1
    It is probably booting to a RISC OS desktop, so before typing those commands it would be necessary to press F12 to drop out to the star prompt.
    – JDHnz
    Commented Jun 16, 2021 at 11:28

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