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I have a Raspberry Pi 2 connected to a Dell 1707FP monitor via an HDMI-to-VGA cable. Every minute or so , the screen will randomly turn black for a second and then return. This occurrence happens randomly. I have tried the cable and monitor with my laptop and they work fine. What is the most probable issue and how might it be solved? Thanks.

  • What software are you running on the Raspberry Pi? – Paul Slocum Jul 12 '17 at 4:32
  • Wait! "Every minute or so" or "This occurrence happens randomly"? So which is it - or it is that every linute there is a chance that it happens. As Paul suggests - what is the RPi doing - what does the top few lines of the top command show? There are numbers there for "average" CPU load as well as current "resources" usage which might give some insight into whether the RPi is a little too busy to maintain a stable system/display. I am not sure but is the HDMI to VGA conversion taking too much power - is there an option to provide the power externally in that case? – SlySven Jul 12 '17 at 5:20
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+50

id say that it may likely be due to power draw, your adapter(the hdmi to vga cable) you are using. If it isn't powered by itself it may be the cause of your problems, as the pi wasn't designed to power active adapters over its hdmi port, and your problem is likely intermittent as it may only occur when the adapters or the pi's power draw spikes such as when the display has a rapidly changing image or when the pi's processor is being utilized to its full capacity. This also explains why the adapter works just fine with your laptop.

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It must be the issue with your cable.
I think you can swap it with the new one (with higher quality maybe), or you can use the HDMI-to-VGA adapter then using the VGA-VGA cable.

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Did you try to config /boot/config.txt, something like below

raspberrypi.org/documentation/configuration/config-txt/video.md says:

Setting hdmi_safe to 1 will lead to "safe mode" settings being used to try to boot with maximum HDMI compatibility.

You may add the line below to /boot/config.txt:

hdmi_safe=1

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I had the same exact problem and was able to correct it. The hardware I was using was

  • Raspberry Pi 3
  • HTMI to VGA adapter and VGA cable
  • An old 800x600 Westinghouse monitor

This was something I haven't seen in years but remembered that some monitors will blank periodically when over-driven. After adjusting the default resolution to 800x600 it stopped. I believe I was over driving the monitor and it wasn't the board or cable.

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