Use iMac G3 CRT with a raspberry pi or any other computer

[Rockyill]

I'v been scouring the internet for documentation on pinouts for the iMac G3 DV so that I could make breakout boards
that plug into the chassis connectors. This way one could 'hook" into the CRT in a nice way.

I have collected and organized some pinouts and made my own diagrams based on my own testing and placed them on github.
There are links to youtube videos at the bottom.

https://github.com/qbancoffee/imac_g3_ivad_board_init

With help from many people I have been able to turn the CRT on and send video to it .

My iMac is missing the audio board where the headphone jacks are in the front. I was wondering if there is anyone out there
that has rung out jacks to the connector on the board.

Any other information will be helpful, just let me know and I'll add it to my github page.

 

[Rockyill]

Here is a link to one of the videos

 

[Rockyill]

If anyone is interested or has more info in the way of sniffed comms between the iMac G3 DV logic board and the IVAD board
please share.

With lots of help, Ive gathered enough info to make three printed circuit boards to convert the iMac G3 DV into a CRT monitor which can
be used by a regular computer with a VGA out.

here is one of the videos.

Here is the link to the repo.
https://github.com/qbancoffee/imac_g3_ivad_board_init

 

[faronk]

I would love to get more involved in this. If you decide to buy a few printed boards let me know. I will help fund!

 

[Rockyill]

I did and built them and they work. I have instructions on how to order them in the repo.

I ordered 5 of each board so I have 4 of each left over. I did make a change to the j22 board but
I haven't ordered an updated one yet in case I make more additions.

Here is the link.
https://github.com/qbancoffee/imac_g3_ivad_board_init#Ordering-Boards

I know they are not the best but I can walk you through it if you have any questions.

 

[faronk]

Dude you are awesome. I have been wanting to put a raspberry pi in a G3 for awhile now. With the release of the Pi 4 recently this makes it a legitimate option for a PC. Are you currently working on any other revisions or optimizations?

 

[Rockyill]

Nah, just like to tinker but thanks.

I just bought a Pi 4 for this project and I hope to have it running with my G3 this week!
So far I have no plans to change the J20 board or the down-converter break-out board but I might make
a change to the J22 board to make it a little easier to connect the headphone jacks.
I'm no sure what to do there yet and I probably won't for a couple of months.

That said you can still use the headphone jacks because they are mapped to a header on the
j22 board.

 

[faronk]

So I spent some time look and this project. This is wayyyy over my head! I have no idea how you could assemble this let along design this project. I am impressed! This is a cool project just a little too advanced for me.

 

[Rockyill]

If you can solder then you can assemble this, it's actually not too bad. I purposely used through hole components
so the only piece of equipment you would need is a soldering iron.

That said, if you don't have any experience with electronics then I can see why this would look daunting.
I'm planning on making some assembly videos and/or sell assembled boards on ebay or something.

 

[faronk]

I'm a super novice when it comes to soldering. If those do pop up on ebay I will be your first purchase!!