Resolved I have decided to hack eMac's CRT (To work with any standard motherboard)

[Sinornithosaurus]

I've connected the milligrid connectors up, and I fed all the necessary wires out through a hole drilled in a spare RAM cover I found on gumtree. It looks quite flashy. Unfortunately I can't get the screen to initialize using the Arduino Uno. The 5v signal coming out of the Arduino turns the monitor on, but the SDA and SCK don't seem to be working as intended. It's a bit of a shame, but I hope I can provide some interesting tidbits for someone else to improve on. I could be missing some basic bootup tricks, or it might even just be shoddy wiring. Either way, I hope the connector thing helps someone out there

EDIT: IT WORKSSSS

I made the mistake of outputting the wrong framerate, and now it's at 1024*768 @ 89hz it finally works! However, the colours are wack and the geometry is off. Now it's time to work out how those hex codes work...

Thank you so much for all this documentation, it's so cool to breath new life into this old eMac!

 

[sharpdad]

Does anyone have a copy of this document:

https://en.wikibooks.org/wiki/How_to_modify_an_eMac_to_use_as_an_external_monitor

It is no longer on Wikibooks and the internet archive is down. I found the GitHub source for the CRT monitor initialization codes so that is very helpful but curious what else is in the above document.

I'm hoping to get a RetroPIE setup running inside an eMac and would love to combine the Arduino + PI if that was at all possible to initialize the monitor. And I'm wondering if I could just get the 5v from the eMac's own power supply vs. using an external power source. Some other links I've run across in my research about this:

https://retropie.org.uk/forum/topic/7116/pi-inside-an-emac-g3

https://drive.google.com/drive/folders/1jM-bTzeZxWBJSQU0w99pKZI4wdh8r2Lb?usp=drive_link

Thanks all!

 

[haramia]

I'm also interested in this mod, the CRT would be a great match for retro games. Without physical geometry controls, how would it be possible to change the image settings though?

 

[sharpdad]

Do you mean screen resolution? I think you are probably stuck with the supported resolutions of the CRT. According to Apple...

Fivescreenresolutions:640by480pixels,800by 600 pixels, 1024 by 768 pixels, 1152 by 864 pixels and 1280 by 960 pixels

 

[haramia]

No, I'm talking about the image geometry. Width, height, angle etc.

 

[sharpdad]

No, I'm talking about the image geometry. Width, height, angle etc.

Not exactly sure what you are talking about but how the monitor displays the 640x480 resolution image or whatever? There is another thread about hacking an iMac with a TON of information as well as custom circuit boards to handle it all, etc.

iMac G3 mod - Video Connector

Hello everybody, Attention : This post is a dupe post from the iMac section coz I have been advised there to repost in the "PowerPC Macs" section. Thanks for your understanding. I have been trying for the last few weeks to include a mini ITX-PC board in an iMac G3 slot-loading while keeping...

forums.macrumors.com

Which links to here:

GitHub - qbancoffee/imac_g3_ivad_board_init: iMac G3 IVAD board initialization with an arduino

iMac G3 IVAD board initialization with an arduino. Contribute to qbancoffee/imac_g3_ivad_board_init development by creating an account on GitHub.

github.com

as well as the eMac specific IVAD code:

GitHub - qbancoffee/emac_ivad_board_init: Arduino code to initialize emac ivad board via i2c

Arduino code to initialize emac ivad board via i2c - qbancoffee/emac_ivad_board_init

github.com

I asked over there whether the iMac custom circuit boards will work for an eMac but haven't heard back.

 

[Sinornithosaurus]

No, I'm talking about the image geometry. Width, height, angle etc.

It's a bit more complicated than just sliders, but you edit the hex codes (of values corresponding 1 to 255) in the initialization file that gets uploaded to the Arduino. The really hard thing is correcting the color ratios, mines still pretty bad but it's fine for games.