Mod G4 iMac with Intel Mac mini innards?

[master4nick8r]

Hi all,
just for sharing some infos:

I've followed instructions in http://hidekyan.cocolog-nifty.com/blog/2009/08/imac-g4-dvi-4-9.html?cid=68274206#comment-68274206, i've soldered a dvi-d connector to tmds cable and used the original screen inverter.
the screen work really good, without needing of luminance modifications, i've so fitted a ionitx d e board inside the dome and a regular atx psu (only the board).

the only problem left is that screen doest works until windows boot, maybe a problem with edid informations sent by the display.. i'm still investigating.

here is a photo

Luca

I tried to wire mine too mine is 17" screen is detected as dvi screen and resolution is also detected 1440*900 but i get no image onit. screen inverter works an screen lightens only no image sometimes i get some bars top to bottom but that's all what am I doing wrong????????????

 

[pgee70]

i have been working on a g4 mac as well.
here are the results
http://www.youtube.com/results?search_query=pgee70utube&aq=f

I removed all the internals of the iMac except the power supply and added in an intel D945GCFL2 motherboard, 80GB SATA hard drive, and extended a monitor cable from a samsung 560V lcd monitor and made it fit into the iMac LCD bezel.
The computer uses a vanilla/retail snow leopard install with the chameleon v2 RC4 boot loader and a custom DSDT.aml file. Hyperthreading is enabled.

be happy to answer further questions.
pete

Hi all,
just for sharing some infos:

I've followed instructions in http://hidekyan.cocolog-nifty.com/blog/2009/08/imac-g4-dvi-4-9.html?cid=68274206#comment-68274206, i've soldered a dvi-d connector to tmds cable and used the original screen inverter.
the screen work really good, without needing of luminance modifications, i've so fitted a ionitx d e board inside the dome and a regular atx psu (only the board).

the only problem left is that screen doest works until windows boot, maybe a problem with edid informations sent by the display.. i'm still investigating.

here is a photo

Luca

this is pretty cool. good work. i am not clear though, did you use the original screen ? if you did then there isn't a need to pull apart the screen/neck which is a huge bonus.

i can't understand the pinout linked to, can you please provide an english alternative? i would really appreciate it.

regards pete

 

[newspimp]

Also, i've used a 15'' imac, i think the 20'' one would be different

The 20" models have the same pinouts from the connector on the display out as do the smaller models, IIRC. The 20" panels also are TMDS compliant, and as I predicted earlier (and someone has finally tested! ) DVI compliant. I still have two working 20" models (one at my home office and one I gave to my father as his first Mac) and one that the display/inverter are good, but the G4 board was fried. That was the one I had originally did work on, but never had time to finish.

Might be time to dig that one back out and finish it up.

Great work!

 

[gregounours]

iMac G4 20" PSU

If some of you decide to mod their iMac G4 20" and decide to do without the internal PSU, I am in search of one. Mine just died last week after I moved the unit from one room to the other. I don't know what happened but the DC-DC board is emitting a small ticking sound. There seem to be one bulging capacitor on the board and I may try to change i but its a tough one.

Anyway, I am back on a 17" now and miss the screen real estate. I found some online for $130 but I am not that desperate If you have one make me an offer.

Also is somebody wants some pictures of the innards of a 20" now is the time to ask it is entirely oen.

 

[drewdle]

I'd love to see the innards. Sorry to hear about your misfortune. 20" must be some nice screen real-estate; I've got the 15", so count me jealous.

 

[666sheep]

If some of you decide to mod their iMac G4 20" and decide to do without the internal PSU, I am in search of one. Mine just died last week after I moved the unit from one room to the other. I don't know what happened but the DC-DC board is emitting a small ticking sound. There seem to be one bulging capacitor on the board and I may try to change i but its a tough one.

Anyway, I am back on a 17" now and miss the screen real estate. I found some online for $130 but I am not that desperate If you have one make me an offer.

Also is somebody wants some pictures of the innards of a 20" now is the time to ask it is entirely oen.

If your 17" is USB 2.0 one (1.0 or 1.25 GHz) you can swap PSU or logic board (in theory GF4MX in 1.0 could work with 20" display) between 17" and 20" .

 

[gregounours]

If your 17" is USB 2.0 one (1.0 or 1.25 GHz) you can swap PSU or logic board (in theory GF4MX in 1.0 could work with 20" display) between 17" and 20" .

Thanks !!!

After having switched the hard drives and closed everything up I realized that I should have checked if the PSU where similar. Oh boy I am gonna have to get the Arctic Silver out of its holster again

EDIT: I just looked into it more and the PSU do NOT seeem compatible between 17 and 20. One difference I can see between mine that fails and picture of board for 17 is the presence of heastsinks on the 20.

EDIT2: I also found a great manual with a detailed dissection if an iMac G4 20: http://ifix.me/Apple Service Manuals/imac/imac_G4_usb2.pdf

 

[pgee70]

success!!!!

hi all
an update on my success with the g4 mods.
using information from this blog, i have got a 15" g4 screen working using a dvi-d cable.

in the image you see the imac screen - i am using an atx power supply to supply power to run the screen. i am using the dvi-d box from my macbook pro and a standard dvi-d cable is connected to it. as you can see the image is fine.
the japanese blog was not quite enough detail on what to do with the b/l of the inverter. i found that if you tied it do +5v via a 1kohm resistor it turned on the screen. however, this meant the screen was on when the computer slept - garbage was displayed on the screen, and it looked like it was harming the inverter. so the fix is to use the 5v off the dvi-d connector, (pin 14) which only gives 5v when the computer is awake.
issues
as the computer goes into sleep mode, the screen shows random gibberish for a few seconds. i have enc. a pin out. the colours on the left are from my monitor cable - yours may be different.
the fantastic thing about this, is that you can use your existing imac screen, and you don't need to pull that bloody swing arm apart! i actually did not pull the screen apart to do this mod at all!
also, i can't seem to get dimming to work. i created a voltage divider using instructions from here to get the 0.9 to 3.3 v required. but it made no difference to the screen.
so i am pretty happy with this, i can use an itx motherboard with dvi-d output to make an new mod!
don't forget to check out my youtube vids!

 

[rab154]

pgee70 that is great work!

so from my understanding you are just splicing a dvi-d into the tmds cable?

any chance you could post a picture of the sleep garbage issue that you have?

 

[adcurtin]

I just finished my 17" conversion as well. I enjoy how it shows up as an iMac when connected to another mac. Sadly, I think either my minidp to dvi adapter is crap, or the panel is not 100% alright, because when using minidp to dvi to drive the panel (from mac mini and new MBP), the blacks have blue and green pixels in them, but when using hdmi from an xbox360, mini dvi on my mini, or full dvi on my old mbp, it works fine.

I got it free from a guy who thought the hard drive died, so he left it in his garage for a while. The mainboard rusted and now refuses to turn on, but the screen thankfully still works.

I do have a question about the inverter though, what is the vcc for the electronics? I have mine hooked up to 5v and it works alright, but i'd rather switch to 3v3 if that's the correct voltage.

Also, what is the voltage range for the brightness pin? I currently have that floating, and i'd love to add a pot to control the brightness. Whenever I connected the brightness pin to 5v or 12v, the inverter or psu disliked it and shut off.

I had to completely figure out the pinout on my own, because my wire colors for the panel were different, and I idiotically removed all the pins from the mobo connector end before color matching. Whoops. Amazingly, the lcd control board had test pads for Edata, Eclk, and VEDID, so that was the first thing I got working correctly.

Here's a pic of the dcc info:
http://i.imgur.com/46UyZ.png

and here's one of the lcd control board that I used to figure out the dvi channels (i'm surprised at the quality of my cell phone camera, I can't believe I can see the traces enough to follow them):
http://imgur.com/mXxdJ.jpg

 

[pgee70]

screen corruption

pgee70 that is great work!

so from my understanding you are just splicing a dvi-d into the tmds cable?

any chance you could post a picture of the sleep garbage issue that you have?

thanks.

yes, i basically did just splice the cable, with a few 1k resistors.
it did take quite a while to do, working out which pin connected to which wire, then soldering the cables, keeping all the shielding.
but it is still far quicker than my first mod, where i extended the video cable through the neck assembly.

a photo is enc. i also made a video http://www.youtube.com/watch?v=rFuFYJfvwf8

 

[adcurtin]

mine didn't take that long, maybe 3 hours. I got my pinout wrong for most of that, trying to go off the picture posted here earlier that didn't have the same color wires as mine (mine had 3 5v lines and 3 grounds too).

I desoldered a dvi connector from an old docking station, and the pins on that were slightly larger than the pins in the connector on the mainboard of the g4. Since I left the crimped on pin connectors on the end of the wires, and just removed them from the connector, it was simply plugging and unplugging them until I got it right, then soldering them (the connections are quite strong once soldered).

The big disadvantage with this is that I don't get a nice board to mount the dvi port on. I haven't actually gotten around to mounting it yet, but I'll get there. I think I'm gonna have to mount it in the top half of the dome though, so I can still completely remove the bottom half easily

 

[rab154]

Hmm i suppose sleep could always be turned off, not efficient but would stop the crazy pattern.

I got a a g4 a while back and was looking into putting a m-itx mobo in and installing snow leopard. However i have no real experience in this field. Any chance you could take a few close ups of the cables? just so i understand the pin out diagram exactly

 

[pgee70]

Hmm i suppose sleep could always be turned off, not efficient but would stop the crazy pattern.

I got a a g4 a while back and was looking into putting a m-itx mobo in and installing snow leopard. However i have no real experience in this field. Any chance you could take a few close ups of the cables? just so i understand the pin out diagram exactly

sorry i can't take that photo. to make the cable i had to keep the original shielding on each pair, then tape it all up, and finally enclose in heatshrink/hotglue.
get: cable heatshrink, solder, a dvi cable, soldering iron, hot glue, insulation tape and give it a try!
the pinout is fairly clear i think.
+ good luck!

 

[rab154]

I think Im definitely going to try this mod over the summer (uni exams atm )

pgee, couple of questions about using m-itx in g4 from your previous mod...

Are you using an external PSU, what motherboard did you use?

I was thinking of using this board mainly so i could add in a Broadcom Crystal HD card to the pci-e slot, thus giving 1080p playback in the latest flash plugin as well as in XBMC. I think i would just get around wireless by using an usb dongle.

Would adding a slimline bluray drive be too ambitious, i was thinking space could be saved by using a ssd. The last two parts aren't the final ones i was thinking of going for, but for just for explanation.

 

[pgee70]

I think Im definitely going to try this mod over the summer (uni exams atm )

pgee, couple of questions about using m-itx in g4 from your previous mod...

Are you using an external PSU, what motherboard did you use?

I was thinking of using this board mainly so i could add in a Broadcom Crystal HD card to the pci-e slot, thus giving 1080p playback in the latest flash plugin as well as in XBMC. I think i would just get around wireless by using an usb dongle.

Would adding a slimline bluray drive be too ambitious, i was thinking space could be saved by using a ssd. The last two parts aren't the final ones i was thinking of going for, but for just for explanation.

hi
details you requested are in my previous post.
re the motherboard - it has hdmi output. you will have better luck with one that has dvi-d output. + you don't need 1080p playback on a 15" screen.
initially, i used a similar board to that, but i was using vga output - and the picture is no where near as good as the mac dvi-d screen output.
+ don't plan on getting a pci-e card inside the G4 imac base. it won't fit.
i am probably going to do another mod soon, and i will use a zotac h55 board + an i3 processor.
good luck with exams!

 

[pgee70]

I just finished my 17" conversion as well. I enjoy how it shows up as an iMac when connected to another mac. Sadly, I think either my minidp to dvi adapter is crap, or the panel is not 100% alright, because when using minidp to dvi to drive the panel (from mac mini and new MBP), the blacks have blue and green pixels in them, but when using hdmi from an xbox360, mini dvi on my mini, or full dvi on my old mbp, it works fine.

I got it free from a guy who thought the hard drive died, so he left it in his garage for a while. The mainboard rusted and now refuses to turn on, but the screen thankfully still works.

I do have a question about the inverter though, what is the vcc for the electronics? I have mine hooked up to 5v and it works alright, but i'd rather switch to 3v3 if that's the correct voltage.

Also, what is the voltage range for the brightness pin? I currently have that floating, and i'd love to add a pot to control the brightness. Whenever I connected the brightness pin to 5v or 12v, the inverter or psu disliked it and shut off.

I had to completely figure out the pinout on my own, because my wire colors for the panel were different, and I idiotically removed all the pins from the mobo connector end before color matching. Whoops. Amazingly, the lcd control board had test pads for Edata, Eclk, and VEDID, so that was the first thing I got working correctly.

Here's a pic of the dcc info:
http://i.imgur.com/46UyZ.png

and here's one of the lcd control board that I used to figure out the dvi channels (i'm surprised at the quality of my cell phone camera, I can't believe I can see the traces enough to follow them):
http://imgur.com/mXxdJ.jpg

hi
i got inspired again. i actually have a working g4 which i have taken apart on the floor.
the green wire (BL ON/OFF) has a voltage of 3.18v, and, its frequency is 30,303 Hz and a duty of 37%. so that means the signal goes on for 12.5 microseconds, then off for 20 microseconds.
so i should be able to make a simple astable multivibrator circuit with a 555 timer chip.
the purple wire - dimmer didn't appear to have a frequency, and is 0.802 to 0.812v with the range of brightness.
this voltage is different to what i have seen in earlier posts.
i am guessing that the screen corruption i have seen is because i just put 5v to the inverter, not pulsing it as it should be.
let me know how you go. if i get further info, i can post it here.

 

[rab154]

hi
details you requested are in my previous post.
re the motherboard - it has hdmi output. you will have better luck with one that has dvi-d output. + you don't need 1080p playback on a 15" screen.
initially, i used a similar board to that, but i was using vga output - and the picture is no where near as good as the mac dvi-d screen output.
+ don't plan on getting a pci-e card inside the G4 imac base. it won't fit.
i am probably going to do another mod soon, and i will use a zotac h55 board + an i3 processor.
good luck with exams!

i read over on insanelymac that the zotac h55 works quite well for osx86, would probably be my choice as well

In regards to the pci-e card, to clear up some confusion i meant a mini pci-e card, so in regards to the zotac h55 i would remove the wifi card from this slot and put in a broadcomm HD Crystal, solely for better flash support and if room for bluray playback, but hey atm this is all pure speculation

however i might be selfish and wait to see your progress on the screen corruption issue

exams are going well, thanks!

 

[rab154]

Hey pgee70, have you made any more progress?

 

[kykim]

Agilent Pixel Board

Hi all,

I just found this discussion, and was wondering if anyone installed the board from Agilent Pixel (http://agilentpixel.com/product.php?id_product=76)?

Originally, I thought I might try to stuff a mini into the iMac body, but now I'm thinking that I could just turn my iMac into a USB/firewire hub, HDMI/DVI monitor and audio passthrough from my mini.

From what I've read here, it should be pretty straight forward.

Thanks for any feedback,
-kevin

 

[pgee70]

Hey pgee70, have you made any more progress?

nothing great.

since i posted that pinout, the inverter pin BL/ON-Off wire should not be tied to 5v.
i found that the backlight uses a 3v 30303Hz, 38% duty cycle signal to turn on the backlight.
i made a 555 circuit up to generate the signal. if you are familiar with a 555 astable multivibrator circuit, you should be able to make one up. to make a astable multivibrator with a duty cycle less than 50% requires a diode over R2 in the circuit.
see http://en.wikipedia.org/wiki/555_timer_IC#Astable_mode
i found a resource on the web to calculate the resistor/capacitor combos and used:
R1 = 750, R2 = 1300, C = 22nf with a diode over R2 (anode to pin 6)

using the 555 circuit helped with this problem a little - there was no cold cathode 'burn in' with the screen but the corruption was still present during sleep/wake.

but i have been promised an imac from work with a larger screen. when i get that i will give the project another go.
i have yet to work on a proper voltage divider for the screen dimmer.

 

[logicturnip]

laptop screen

Hi all
I've been following this thread as this project is a great idea! Bravo to all you clever chaps that have got this working using various different methods! I'm hoping to piggyback on your success and attempt this mod myself.

I'd just like to know if it would be possible to use a laptop screen and an LVDS controller to replace the monitor?

I was hoping to up the resolution at the same time, but the only montors available in 17 inches at a higher resolution are laptop one, such as this.

Seems possible I think, based on what I have read. I was hoping that the thinner screen would allow the controller to be placed behind the screen, and then feed power and VGA/DVI through the neck. What do you guys think?

Andy

 

[pgee70]

Hi all
I've been following this thread as this project is a great idea! Bravo to all you clever chaps that have got this working using various different methods! I'm hoping to piggyback on your success and attempt this mod myself.

I'd just like to know if it would be possible to use a laptop screen and an LVDS controller to replace the monitor?

I was hoping to up the resolution at the same time, but the only montors available in 17 inches at a higher resolution are laptop one, such as this.

Seems possible I think, based on what I have read. I was hoping that the thinner screen would allow the controller to be placed behind the screen, and then feed power and VGA/DVI through the neck. What do you guys think?

Andy

Hi andy
i don't have a lot of hope for your proposal..
laptop screens use different protocols.(LVDS vs TMDS) so unless you put a laptop motherboard or you get a generic controller board that can convert LVDS into DVI/VGA. i don't think it will work.
it is possible to put an inverter board into the back of the imac screen.
Pete

 

[gregounours]

Spare PSU for a 20 any one?

I have been following this thread for a while now and I glad to see all these success. I am now seriously considering converting my 17" but I am not ready to let go of my 20". It would be easy though, it is cracked open on my work bench awaiting a new PSU. If anybody has one laying around or is planning to convert a 20" soon let me know. I am willing to shelves out some $$ for it, but not the $130 that different sites are asking for out there.

 

[SchaSche]

Is it possible to connect the LCD panel with the CCFL inverter for a standby function (screen blank and backlight off)? This would be a great funktion, otherwise the screen is always on.

I have an empty iMac G4 with the 20" display, and it would be a beautiful display!