[mdlug] VGA will not work on Raspberry Pi 3

[Dr. Robert Meier]

Gib,

The Raspberry Pi organization chose to drop support for VGA.
See  https://www.raspberrypi.org/help/faqs/#videoVGA  for details.

HDMI-A is an inexpensive (<2USD) in bulk (attractive for Raspberry) 
digital physical layer specification.
IIRC, the link layer chosen for Raspberry Pi was  timing-flexible 
EIA/CEA-861 (attractive for internationalization).

Consequently, I believe you will need, and I assume you already have,
active HDMI<->VGA adapters (i.e. digital-to-analog converters).
Additionally the monitors and Raspberry Pi must both support and
use the same timing.

IIRC, prior to VESA (~1995?), VGA had no timing standards.
Manufacturers and models differed widely.
xvidtune(8) was used to prevent resistive loading from setting CRT 
terminals on fire.

I suspect that your older VGA terminals
   1 do not by default use the same timing as the default Pi settings.
   2 do not identify their available timing choices (e.g. E-EDID)
   3 do not support software timing selection (e.g. DDC)

If you can find requisite documentation, you may be able to explicitly 
select VGA timing of the monitors, by dip switch or configuration button 
settings.

Though uncertain, i suspect you can explicitly set Raspberry pi timing 
in /usr/share/X11/xorg.conf.d/ using xvidtune(8).
I have not examined any of the online sources in detail, but google 
'raspberry pi xvidtune' returns hits that may be helpful.



If you would like to demonstrate the Raspberry Pi analog TV output,
I have a Zenith B&W portable TV (that I assembled in undergraduate) that 
I can lend you.  (It worked in 2014.)



On 10/02/2016 10:39 PM, Gregory Czerniak wrote:
> Sorry...the file is called config.txt in /boot (at least in Raspbian).
> Here's a link to all relevant settings:
> http://elinux.org/RPi_config.txt#Video
>
> hdmi_safe = 1 may also be useful (it also sets hdmi_force_hotplug to 1).
>
> On Sun, Oct 2, 2016 at 10:35 PM, Gregory Czerniak <gregczrk at gmail.com> wrote:
>> Try setting in boot.conf:
>>
>> hdmi_force_hotplug=1
>>
>> On Sun, Oct 2, 2016 at 8:26 PM, gib at juno.com <gib at juno.com> wrote:
>>> I've purchased 5 Raspberry PI 3 boards for the Conclave event next weekend.  But I can not get the old VGA monitors to work.  I picked up some HDML to VGA converters but they will not work with the old monitors.  When I use the same converter with a newer monitor that uses both VGA and DVI it works fine even though I'm using the same cables and converter.
>>>
>>> So, I only have 2 working monitors for my 5 Raspberry PIs.
>>>
>>> The other working monitor is a DVI that I use with a VGA to DVI cable.
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