HDMI to VGA makes disturbed picture on screen

kaltefusion

Hi @ll,

I have an old arcade cabinet with an old original monitor. All wiring is perfectly done by a pro. Raspberry 3b+ is set-up with retropie 4.4 and working on my HDMI flat TV.

But when connected via this adapter and even connected to the pie with the 5v power cable it makes a disturbed picture.

I checked the config.txt and I know the video options are over here but it seems as far as I know that I put everything right.

Here is my config.txt

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on
gpu_mem_256=128
gpu_mem_512=256
gpu_mem_1024=256
overscan_scale=1

Any clue anybody? Appreciate it :)

chipsnblip

hmm, maybe try removing the hash symbol in this section of the config:

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=1
hdmi_mode=1

i'm not sure about that adapter, have you considered using a GPIO-based adapter for video out? something like the Gert VGA 666, or even a retrotink.

kaltefusion

thanks...I will try and respond

edmaul69

@kaltefusion what is your resolution you need to setup? Having hdmi mode set to 1 and hdmi group set to 1 might not be the correct setting.

kaltefusion

@edmaul69 Well actually I have no idea. This is an old arcade uprigt cabinet with an old monitor. I dont know the resolution of those. But I thought putting a "1" forces VGA so I thought it might work. But it does not obviously.

Would be really thankful if you have any further idea :)

cheers!

kaltefusion

@chipsnblip unfortunately that did not work out :/

Would be very thankful if you have any other clue..

edmaul69

@kaltefusion does the monitor have vga? If so then the resolution is either 240p or 480p. You need to set the settings according to that. However it still might not work without the correct adapter that changes it to 15khz or 31khz. Without knowing what monitor or game it was i cant tell you if there is a switch to change what frequency the monitor outputs i cant really advise you what to do.

kaltefusion

@edmaul69 Thanks so far. It's not really a monitor. It is a tube monitor. It does not have VGA . But a pro made the wiring changes that it is now connected via JAMMA.

And from the raspberry there is a HDMI out to VGA with this adapter which goes into a J-PAC. And that is connected to the JAMMA interface of the Arcade.

I heard it too that the frequence should be set to 15hz.
But what kind of settings do I have to adjust for that? Or the resoution?

Thanks mate!

edmaul69

@kaltefusion so rewiring isnt going to work ever. Rgb isnt quite the same as vga rgb. You need an adapter like this:

https://www.ebay.com/itm/VGA-TO-CGA-CVBS-S-VIDEO-CONVERTER-PC-to-VGA-Video-Game-Converter-Board-GBS8100/253068345466?hash=item3aec0c807a

Then you need to adjust your config.txt. This setting might work for you

hdmi_drive=2
# defines the HDMI type CEA/DMT, 0 will use the preferred group reported by the edid.
config_hdmi_boost=6
hdmi_ignore_edid=0xa5000080
hdmi_group=2
hdmi_mode=9
disable_overscan=1

edmaul69

@kaltefusion

In this link are the hdmi modes for group 2. Make sure you look at group 2’s
https://www.raspberrypi.org/documentation/configuration/config-txt/video.md