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Pedro147

macrumors member
Sep 23, 2016
36
21
Australia
For those who aspire to connect an HDMI source to the G4 screen I am having some TMDS to HDMI breakout boards made in the coming weeks so you can just plug the very unique video cable right into the board and wire it up as you like (may be different pins to connect depending on whether you have a 15"/17" or 20" G4 stand by for more updates in the coming weeks.
Nice work and although my G4 still sits waiting, I am definitely interested in this board while they are available.
 

PML7554

macrumors member
Oct 8, 2021
35
97
For those who aspire to connect an HDMI source to the G4 screen I am having some TMDS to HDMI breakout boards made in the coming weeks so you can just plug the very unique video cable right into the board and wire it up as you like (may be different pins to connect depending on whether you have a 15"/17" or 20" G4 stand by for more updates in the coming weeks.
Can’t wait to see this board! I was dreaming about something like that, but I don’t have the skills or tools…
 

joeventura

macrumors newbie
Mar 22, 2024
20
17
Can’t wait to see this board! I was dreaming about something like that, but I don’t have the skills or tools…
Its coming soon, probably mid april
 

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joeventura

macrumors newbie
Mar 22, 2024
20
17
If you'd like to help in creating a final board that is an adapter vs a breakout (i.e. prerouted to work without jumpers) let me know if you have a pinout to try
 

mang0s

macrumors newbie
May 14, 2024
3
0
Im realy waiting for this. I collecting parts to do the conversion on a 20" version. The next adapter that would be needed is for original speakers. My plan was cuting the amplifier from the G4 motherboard but it seams a bit harsh.
Was also looking at Juicy Crumb Systems adapter board that has everything, but its realy expensive and is aimed at converting the G4 to an external display.
 

joeventura

macrumors newbie
Mar 22, 2024
20
17
Im realy waiting for this. I collecting parts to do the conversion on a 20" version. The next adapter that would be needed is for original speakers. My plan was cuting the amplifier from the G4 motherboard but it seams a bit harsh.
Was also looking at Juicy Crumb Systems adapter board that has everything, but its realy expensive and is aimed at converting the G4 to an external display.
Well its ready for prime time

 
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PML7554

macrumors member
Oct 8, 2021
35
97
Im realy waiting for this. I collecting parts to do the conversion on a 20" version. The next adapter that would be needed is for original speakers. My plan was cuting the amplifier from the G4 motherboard but it seams a bit harsh.
Was also looking at Juicy Crumb Systems adapter board that has everything, but its realy expensive and is aimed at converting the G4 to an external display.
To use the original speakers, you can use an amplifier board based on a TA2024, that is the original chip embedded on the iMac main board.
I soldered cables on the iMac cut main board to use the original connector, and powered it with a dedicated power brick.

IMG_0402.jpeg
 
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mang0s

macrumors newbie
May 14, 2024
3
0
To use the original speakers, you can use an amplifier board based on a TA2024, that is the original chip embedded on the iMac main board.
I soldered cables on the iMac cut main board to use the original connector, and powered it with a dedicated power brick.

View attachment 2377905
This is the board we should remake with right alignment on connectors and TMDS-HDMI converter and TA2024 amplifier. What is the model on the board connector of TMDS?
 

elinks

macrumors newbie
Jul 19, 2011
17
0
First working prototype
Joe, This is an interesting project. I have successfully completed the re-wire of the display TMDS wiring on my iMac G4 and would not like to do that again. I want to retrofit another 17in and am curious about the inverter wiring. Is the inverter wiring out of scope in your project? Do you know the P/N of the mate-with connector for the black G4 inverter cable? Do you have plans for an actual adapter, en lieu of your breakout card? TIA
 

joeventura

macrumors newbie
Mar 22, 2024
20
17
Joe, This is an interesting project. I have successfully completed the re-wire of the display TMDS wiring on my iMac G4 and would not like to do that again. I want to retrofit another 17in and am curious about the inverter wiring. Is the inverter wiring out of scope in your project? Do you know the P/N of the mate-with connector for the black G4 inverter cable? Do you have plans for an actual adapter, en lieu of your breakout card? TIA
Nothing is out of the realm of possibilities.

Do you have a design in mind you could share?
 

elinks

macrumors newbie
Jul 19, 2011
17
0
Nothing is out of the realm of possibilities.

Do you have a design in mind you could share?
I did document my work when I performed the mod the first time and I could share it with you. I was thinking a breakout card like yours that also included a m/w connector that matched the inverter connector from the neck where the pins were broken out and easily accessible. The user would obviously be required to wire in inverter power, hot pin detect, VEDID and brightness control. These functions are obviously not detailed in this illustration.
 

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joeventura

macrumors newbie
Mar 22, 2024
20
17
when I was prototyping I just made the attached board to attach the plug, just two rows of header pins.
 

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elinks

macrumors newbie
Jul 19, 2011
17
0
when I was prototyping I just made the attached board to attach the plug, just two rows of header pins.
I left the purple and orange floating, like this, and ran hot pin detect thru 1Kohm resister to the red inverter wire. If the inverter connector is broken out, all that would be left is for the user to jumper in 12v power/gnd and a 3.3v dimmer/brightness control. What do you think? An all-in-one adapter card. The TMDS/HDMI signals don't necessarily need to be broken out, with the exception of HDMI pin 18 (VEDID) and the Hot Plug Detect/Gnd, but you already have them broken out.
 

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joeventura

macrumors newbie
Mar 22, 2024
20
17
If someone wants to do a design (schematic with BOM) I am happy to get the board designed and produced.
I just don't have the time to do the design and prototyping. I have a lot of projects in the air right now.
 

elinks

macrumors newbie
Jul 19, 2011
17
0
If someone wants to do a design (schematic with BOM) I am happy to get the board designed and produced.
I just don't have the time to do the design and prototyping. I have a lot of projects in the air right now.
I can appreciate that. I would do it but I am presently upgrading an iPod Classic 5th gen with micro SD card and larger battery and looking to design an VESA mount to iMac G4 neck mechanical interface to 3D print to attach a larger/higher resolution monitor to one of my G4s. Maybe later this fall we can come back to this. I might still purchase your breakout card to do some prototyping. Thank you for the discussion.
 

elinks

macrumors newbie
Jul 19, 2011
17
0
sure thing. BTW that little breakout card is selling like hotcakes!! LOL
congrats! Just had another thought ... a breakout card like we discussed with a 12 vdc plug and a DC-Dc step down coverter and then all one would need for an external monitor would be HDMI and 12 VDC power (also need 1k ohm resistors on-board)
 
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