Connecting Pi3b to RGBHV CRT Monitor

lillythebear

Raspberry Pi 3b
Canakit DCAR-052A5 (2.5A Power Supply)
RetroPie 4.7.1 (RPI 2/3)
Installed via Raspberry Pi Imager
Only USB Keyboard attached so far

Hi y'all, I'm a bit in over my head.
(This post is also on reddit)

Recently bought a Sony Trinitron GDM 1950, it supports 1280x1024 & 1024x768 @ 60hz (Not traditional 240p or 480p, but thought it would look nice still). Currently connected to my raspberry pi 3b via RGBHV -> VGA -> HDMI, to not much surprise I'm not getting a picture on the monitor, just lots of odd static and lines.

I'm currently using the following in the config.txt:

(I am barely grasping these settings I should add, it's most likely a mess)


hdmi_ignore_edid=0xa5000080
hdmi_group=2
hdmi_mode=35

config_hdmi_boost=7

dtparam=audio=on
hdmi_ignore_edid_audio 1

Is my code scuffed to try and display 1280x1024, or is it a hardware issue? Do I need to buy RetroTINK Ultimate or VGA666 to get this to work?

In the meantime, I've bought a new VGA to RGBVH cable just in case the one that came with the monitor was bad... Needless to say I have gotten way in over my head here, any sort of advice or guidance would be greatly appreciated.

mitu

Have you tried with a lower resolution video mode (1024x768@60hz) ?

lillythebear

@mitu Would my config file than look like this for a forced 1024x768 (while routing audio to 3.5mm jack):


hdmi_ignore_edid=0xa5000080
hdmi_group=2
hdmi_mode=23

config_hdmi_boost=7

 dtparam=audio=on
 hdmi_ignore_edid_audio 1

Mainly trying to discover if it's an issue with config or a hardware issue (I'm worried I'm using too many adaptors for video).

mitu

@lillythebear You should only add the HDMI resolution options, you can remove the hdmi_ignore_edid_audio line since it's incorrect and it doesn't do what you want (i.e. it would force audio over HDMI which is not what you need).
You should post the entire config.txt instead of just stray lines.

I'm worried I'm using too many adaptors for video.

How many converters/adaptors are you using and which ones ?

lillythebear

@mitu Apologies let me post the config.txt file, most of it is commented out. I did however remove hdmi_ignore_edid_audio:

https://pastebin.com/yMT65SK2

As for converters & adaptors, I am using the following:

(From the Pi)
HDMI to female VGA

male VGA to RGBHV BNC (That's the only input option my CRT Monitor takes)

I am replacing the vga to bnc cable tomorrow, which is when I'll try to get the retropie up and running again.

If the new cable doesn't work with a working config.txt (correctly forcing 1280x1024 60hz or 1024x768 60hz), I will either have to get a RetroTINK Ultimate or VGA666 into the GPIO pins, if that fails than I suppose this CRT is just busted.

lillythebear

Updates!

I have gotten somewhat of a picture to have display (IGNORE THE MESS 🤣)

https://i.imgur.com/uCDczXZ.jpeg

This was achieved using the following modelines in the config.txt

hdmi_ignore_edid=0xa5000080
config_hdmi_boost=4
hdmi_group=2
hdmi_mode=87
hdmi_force_mode=1
hdmi_timings=1024 0 48 104 152 768 0 3 4 23 0 0 0 60 0 88509090 1

It's still obviously very distorted but what is odd that the pixel clock I'm using, 88.5MHz was the only way to get some semblance of an image. However according to the manual for my display it should be a pixel clock of 64MHz for 1024x768 60hz (resolution I'm using rn) and a pixel clock of 108.18MHz for 1280x1024 60hz

Any reason why the pixel clock is so off? Is my code still wrong? Ultimately I think this will boil down into me opening up the CRT and messing with the sync pots but I'd like to avoid that if possible.

Any further guidance or help is greatly appreciated 😄.