hdmi to vga converter question

[cadence]

Hi. I am using http://thepihut.com/products/raspberry- ... -convertor to convert a good hdmi signal to vga as I want to use r pi in a kids coding club where vga monitors are only available. The pi is model a. I have verified hdmi with a tv but am at a loss why no vga signal is seen. I have turned on hdmisafe on config.txt but no joy. Any thoughts appreciatef.

[DougieLawson]

With the VGA adapter plugged in what do you get from a
tvservice -m DMT
command? You can use the values returned from that to update /boot/config.txt (use the NOOBS recovery system if your SDCard has that to edit the right config).

The starting point for most VGA adapters (almost 100% guaranteed to get a picture) is
hdmi_group=2
hdmi_mode=4
which gets it running at the truly clunky 640x480 @ 25MHz

Next test is
hdmi_group=2
hdmi_mode=16
for 1024x768 @ 65MHz

[W. H. Heydt]

which gets it running at the truly clunky 640x480 @ 25MHz

25Hz

for 1024x768 @ 65MHz

65Hz.

Those are refresh--aka "frame"--rates. If the OP is in the US, he should look for a 60Hz refresh rate to start with.

Also...check the back of the monitor(s) to be used. Get manufacturer and model. Look it up on line to get the native resolution and refresh rates.

[DougieLawson]

What's two orders of magnitude between friends?

[davidcoton]

What's two orders of magnitude between friends?

Not a lot, but six orders is pushing it a bit.

(Order of magnitude is a factor of 10. You are two orders out in your interptretation of it )

[cadence]

With the VGA adapter plugged in what do you get from a
tvservice -m DMT
command? You can use the values returned from that to update /boot/config.txt (use the NOOBS recovery system if your SDCard has that to edit the right config).

The starting point for most VGA adapters (almost 100% guaranteed to get a picture) is
hdmi_group=2
hdmi_mode=4
which gets it running at the truly clunky 640x480 @ 25MHz

Next test is
hdmi_group=2
hdmi_mode=16
for 1024x768 @ 65MHz

Tks. This worked, i.e.
1024x768 - tks.