retiredsailor
Posts: 4
Joined: Sun Dec 30, 2012 6:05 pm

HDMI to VGA problem

Thu Jan 03, 2013 11:12 am

1) Rasberry Pi supplied by RS in December 2012
2) A black moulded plastic case (from RS) to house the Type B Raspberry Pi
3) CABLE MATTERS GOLD PLATED PREMIUM HDMI to VGA ACTIVE M/F ADAPTER
4)16GB branded (Kingston) SDHC SD Card preloaded with latest Raspian "wheezy" Linux O/S & partitioned to use full memory.
5) EXTRA LONG UK Micro USB Mains Power Wall Supply Charger For Raspberry Pi - (1000mAh / 1A) Sold by: IBOX.CO.UK LIMITED

Hello,
Connecting HDMI to HDMI everything works fine. However connecting HDMI to VGA (via the adapter) the video signal to the monitor intermittently fails. I have read that adjustments in config.sys may be needed. Can you please advise and also explain how I get to 'config.sys' and what the parameters should be.

Many thanks.

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malakai
Posts: 1382
Joined: Sat Sep 15, 2012 10:35 am
Contact: Website

Re: HDMI to VGA problem

Thu Jan 03, 2013 11:40 am

Don't have a hdmi to vga so not sure but config.sys is a Windows system

Your after the config.txt here are a few links that might help

http://elinux.org/R-Pi_ConfigurationFile

http://elinux.org/RPiconfig

http://elinux.org/RPi_Verified_Peripher ... rter_boxes
http://www.raspians.com - always looking for content feel free to ask to have it posted. Or sign up and message me to become a contributor to the site. Raspians is not affiliated with the Raspberry Pi Foundation. (RPi's + You = Raspians)

pitt
Posts: 13
Joined: Fri Dec 28, 2012 4:06 pm

Re: HDMI to VGA problem

Thu Jan 03, 2013 1:27 pm

Hi,
as far as I know, these cables only work with computers on which you can switch the HDMI port to output an analog VGA signal. As far as I know, Raspis can't do so. In order to attach a VGA Monitor to the Raspi you'd need a HDMI-DAC, for example this one
http://www.amazon.de/HDMI-VGA-Konverter ... B004RUBIOG
I have no clue at all if this will work with the Raspberry Pi, though. There's more information out in the web on this. Google is your friend...
Cheers
Pitt

retiredsailor
Posts: 4
Joined: Sun Dec 30, 2012 6:05 pm

Re: HDMI to VGA problem

Thu Jan 03, 2013 2:00 pm

Hi Malakai,
Thank you for the info, it explains a lot and should help me to resolve the problem.

Hi Pitt, thanks for that. I bought the adapter from Amazon and all the reviews claimed it should work with the Rasberry Pi. It almost does but it's very annoying when the screen goes blank every few seconds.

Cheers and Happy New Year.

toxibunny
Posts: 1382
Joined: Thu Aug 18, 2011 9:21 pm

Re: HDMI to VGA problem

Thu Jan 03, 2013 3:36 pm

It's an active adaptor, but of the type that's not really recommended to use with the pi (ie. it takes the power from the pi's hdmi port rather than an external source). If it's already almost working, there's probably not really much you can do with the config.txt, other than maybe changing/using the HDMI BOOST option. Other than that, there's the usual thing of trying different power supplies, trying it with nothing else connected, and eventually maybe opening up your adapter and patching in an external power supply...

Some people are lucky and it works no problem. Others aren't so lucky... http://www.raspberrypi.org/phpBB3/viewt ... =28&t=9819
note: I may or may not know what I'm talking about...

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johnbeetem
Posts: 945
Joined: Mon Oct 17, 2011 11:18 pm
Location: The Mountains
Contact: Website

Re: HDMI to VGA problem

Thu Jan 03, 2013 8:32 pm

IMO you most likely have a power supply problem. The amount of current RasPi uses depends on what it's doing, and if you have an iffy Micro USB cable or polyfuse F3 the additional current can cause RasPi's 5V (measured between TP1 and TP2) to droop enough to make your HDMI device sad. For example, at one time I had an iffy power connection which worked fine unless I ran the gcc compiler, in which case the extra current needed by RasPi's CPU caused little green dots on my monitor.

One possible culprit is your "extra long" power supply cable. In general, its better to have a short Micro USB cable so that there's less of a voltage drop between the power supply and RasPi.

There's a good section on diagnosing power supply problems at the RasPi Troubleshooting Wiki: http://elinux.org/R-Pi_Troubleshooting# ... r_problems

retiredsailor
Posts: 4
Joined: Sun Dec 30, 2012 6:05 pm

Re: HDMI to VGA problem

Fri Jan 11, 2013 9:11 am

Many thanks for the replies.

I agree it looks as though I have a psu problem so it's back to the drawing board.

Regards

Trey
Posts: 4
Joined: Sun Sep 16, 2012 2:40 pm
Location: Austin, TX
Contact: Website

Re: HDMI to VGA problem

Sat Jan 12, 2013 8:21 pm

I have this same Cable Matters HDMI to VGA adapter with a 512mb RPi board. I couldn't get any video at first, then I noticed that the HDMI to VGA adapter itself has a micro USB port right next to the 3.5" audio out. I supplied it with power via this port, and haven't had any problems since. No special config_hdmi_boost or other video settings necessary on my side.

Here's the really cool part (I think): I use this PSU (http://www.amazon.com/gp/product/B0073FCPSK/), and I can use one port to power the RPi, and the other to power the HDMI to VGA adapter. I use this configuration with my RPi overclocked to "Fast" (950mhz) and haven't had any problems. It seems the black adapter I bought is not currently available, but they have a very similar looking one in white: (http://www.amazon.com/PowerGen-Dual-Por ... 0073FE1F0/).

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