Ersterhernds iMac G5 20 Inch A1076 Project

[rkona]

It would be a first on this forum to see anyone fit a mini-itx board into a white iMac. Space is VERY limited inside these machines.


Cheers!

Challenge (possibly) accepted. The Thin Mini ITX Board is designed for all-in-ones and is about 8 inches square. It would be very tough on the 17 and 20, but I think that the added square footage of the 24 might make it work. The only problems I see with this configuration are that the LVDS cable comes up at the foot of the computer- near the IR sensor and power port. If I decided to do this, I might have to run the power cable through the FireWire port.

I'll look into this mod more closely. I can assemble machines, but the inverter and PSU wiring might be a whole different story.

Thanks,
rkona

 

[ersterhernd]

I'll look into this mod more closely. I can assemble machines, but the inverter and PSU wiring might be a whole different story.

Thanks,
rkona

Found this on the 24" panel. Looks like 72W just to power the backlights. Yikes, thats over double the 20" requirement, and 6x the 17" power requirement.

http://www.panelook.com/LM240WU2-SLA1_LG Display_24.0_LCM_parameter_4977.html


Definitely a challenge. It'd be incredible to see an iMac mod running those kind of specs.



Ersterhernd

 

[pixys]

Hi Ersterhernds,

I was amazed when I saw your iMac G5 moding : you truly did a terrific job , and gave so many detailled informations... Thinking to a similar project, I decided myself to find more info : I will thank you a thousand time if you can share some of your expertise to help me in this project.

Above that, let's say :

• I'm quite a newbie in Hackintosh moding, even if I'm familiar with PC assembly and not afraid of a little customisation/soldering/Dremeling...
• I'm french and my english sometimes must appears awkward... By chance, you don't have to deal with the accent

So, let's start the story and come to the point(s). In 2005, I bought an iMac G5 1.8 Ghz (M9250LL/A), which did perfectly is job until 2012 ; then, the machine began to display strange artefacts, and froze and finally did not display anything > video board HS. After a few researches on the web, I decided to keep it and find a way to re-use the very good 20'' LCD panel. A that time, I began to think about integration of a full macMini into the G5 case.

I recently saw that such moding had been done – iMac G4 by Panici or macMiniin a G4 Cube

Almost 3 years have passed, until I found on eBay a pretty good bargain on a late 2012 core i5 macMini. Now, I have to take the plunge and try to make a nice « full-Apple » built, hoping I'm not going to ruin everything...

First step > the LCD connector :

I worried about the soldering of HDMI port to genuine LCD wire harness so I searched Google for an alternate solution and I found this :

• FIX-30P-S8 30 Pin to 30 Pin LVDS Cable for LCD Panel Display
• FIX-30S-2LVDS

Both cables are compatible with the 20'' panel (LM201W01-SLA1), according to the attached pinout diagram ; it would be easier to cut the end of the wires – or use the connector – and splice to an HDMI female plug. (this one is a french reseller). The announced prices are a bit odd : ten pieces of the first model for $ 12,90 ( and ship for free...), and $ 27,99 for the single one... I must order the bunch of ten and try to resell on eBay

Here I want your expertise : assuming that I'll use the display on a macMini, I won't have to deal with the brightness control...Correct ?

2nd step > powering up the system :

I found various explanation about re-using the G5 PSU and none was detailled enough for my little lazy brain. So, i'll be glad if you can confirm that my ideas are ok :

• I have to connect the backlight inverter and pannel to PSU ; I'll make my own connector using ATX-PSU parts and pins found on that (french) site. A little picture or schema of your own will be appreciated
• I'll must also splice the macMini AC line from the PSU, as you do for your NUC ; that won't be too difficult.
• Managing to power up the whole system : the best way seems to re-use the G5 power switch, but I don't clearly see how to achieve that... Could you provide some help ?

It will be cool to realize that first and have a decent mac working with my G5 display ! After that, I must find the best way to insert the mini into the iMac case and manage with the I/O ports. The simplest way is a large cut on the G5 case side : could do the trick if properly done. The better way will be to make a dedicated connector, re-using the genuine cut-off on the G5 back... Probably a pain in the ass.

Here is where I am for now, with a beginning of headache for on hour and half of english redaction. But I'm very excited about this build and can't wait to have your (& all community members) precious advices.

Best regards

pixys

 

[ersterhernd]

Hi Pixys,

I am not familiar with the Mac Mini as I've never owned one or had one apart. Your post talks about using an LVDS cable run to the iMac LCD. Beware that the panel is not LVDS, but rather TMDS signalling. TMDS is directly HDMI compatible so thats what has been used by myself and several others on this forum. There isn't a simple plug n play approach that I've seen so far to accomplish this. The iMac G5 video cable must be cut and the delicate signalling wires must be carefully stripped for soldering to an HDMI end. I've completed four such cables, three of which are still in use in G5 mods, and one is a spare in case of a failure. It is tedious work, first accomplished by kiwisincebirth. He gets the credit for pioneering this, and documenting his methodology.

If you can find a simpler approach, good on you. Just beware that TMDS pinouts are radically different from LVDS, which you may know already.

Your screen brightness will need to be controlled via the variable voltage (max 3.3v) line on the inverter. I chose to use a simple potentiometer that proved to be a functional and aesthetically viable solution for the iMac G5. Kiwi and MacTester pioneered a more elegant solution of OS X control, but it is much more involved in both hardware and software. Regardless of how you do it, the inverter will need to be utilized to accomplish effective brightness control of the LCD. A challenge of this is that it requires 24V, so reuse of the original PSU in the iMac is pretty much a must-do, as it contains a 24V pin.

The PSU itself presents the problem of actually switching the iMac on and off. Again, Kiwi and MacTester accomplished this with a separate microcontroller, whereas I used a 2nd PSU and the Intel NUC to trip an optical relay and short the PS_ON pin to GND on the iMac PSU. Either way, the iMac PSU must be switched from standby mode to powered on somehow, and this may require some thoughtful engineering on your part.

The power switch on the back of iMac contacts the iMac logic board by way of 2 small copper plates. The Intel NUC Power Switch pins (on the FP Header) are wired directly to the iMac logic board as an extension of the on/off circuit. When the button is pressed, the circuit closes momentarily and the NUC powers up. The iMac logic board must be traced to find the proper + and - location of power switch on the board. iMac logic boards vary, and may differ from one another in finding the soldering locations.

There's only one way to accomplish the a clean mod of the rear I/O as original, that is by reuse or modification of the existing ports on the logic board, and installation of that corner of the board inside the iMac case.

Your biggest challenge may be actually fitting a MacMini inside a G5. There is VERY limited space, and the window of opportunity is very small in what will actually fit while allowing the iMac to close up properly for use. This of course is paramount to even proceeding with the build or not. Test fitting all main components must be successful, and cutting the outer shell of the iMac would only destroy the purpose of the build, in my opinion.

Hope this answers some of your questions. This response was typed on my iMac G5 A1076 model, which is up and running for nearly 8 months now. I use it almost every day, its on 10.10.3 now.

Good Luck.


Ersterhernd

 

[pixys]

Hi Ersterhernds !

And thank you for your detailled answer... and for saving my life !

I just totally miss the point about my panel and was about to make a confusion with another model Here is a pic of my panel, showing the maker's reference :



It shows very well the (A5)(K2) suffix, and I focused myself on the (SLA1) type... which has an LDVS interface !

Just beware that TMDS pinouts are radically different from LVDS, which you may know already.

LoL ! I know so few about TMDS/LVDS pinouts, I thought this was just a matter of signal encoding, but that seems to involve different ways of pairing and twisting the wires... Many reasons which lead to unnecessary complicate the job...

I just wanted to use a new cable because the genuine one is so hard to work with, with the tiniest wires I have ever touched... I'm terribly afraid to waste it, in my attemps to solder it to an HDMI plug... By now, I've downloaded Kiwi's explanation about LCD conversion, I'm gonna translate it to figure out better.

I now understand the point about brightness control. Softwares - even genuine Apple OS - can't control 100% of the brightness ; all displays have external buttons to adjust and that's why the use of a potentiometer is needed. The way you use it, by the DVD opening slot is pure genius

I think it will be enough work for the moment ; I'll be very glad to manage to power on my screen and display a correct HDMI signal. I'll will be back for further informations about the macMini and I/O ports if needed, which will surely happen

Thx a lot again for your expertise and kindness !

pixys

 

[ragev]

It would be a first on this forum to see anyone fit a mini-itx board into a white iMac. Space is VERY limited inside these machines.

It seems to me, looking at your photos, that there is space in the horizontal and vertical directions. If the problem is in the height of the board with ports and cooler, would a thin mini-itx board not be thinner than the NUC? It appears to me that the NUC, because it has the CPU and ports on opposing sides of the PCB sacrifices a slim profile for the gain of shrinking the size of the PCB from 170mm to 100mm or thereabouts. I know I can find thin mini-itx boards which are no more than 29mm thick CPU heatsink and fan included. Could you shed some light on how thick the NUC board is?

-Ragev

 

[ersterhernd]

Hi ragev,

The build photos of the iMac are a little deceiving because they don't show depth very well. I've included a full-size photo of my second A1076 project (completed three in total) to illustrate this point.

The entire space on top of and to the right side of the 7mm thick Crucial M500 SSD is unusable due to the hinge that connects to the iMac stand. The backlight inverter limits the horizontal and vertical placement of the components on the right. You'll see where the NUC is sitting is really the only space usable in my configuration. I will never say never, but I'd be really surprised to see a mini-ITX board stuffed into the finite space of the iMac. Sorry I dont know the depth of the NUC, but am sure its available on the Intel technical product specs sheet.

The NUC fit my needs (and my iMacs) just perfectly. The goal was a quiet, functional and lower power all-in-one solution which the Intel NUC made possible in my opinion. Of all the systems I've built, this A1076 gets the most consistent use of the bunch.


Cheers!

 

[Superspick93]

Hey I recently got my old iMac running again.. Failed PSU which was pretty common in these machines so I've read.. How difficult of a build would you say this would be for someone who has never attempted a build like such? I would hate to get rid of this machine but just not much a I can do with it. awesome build man I'm in awed of what you and kiwi did

 

[ersterhernd]

Hey I recently got my old iMac running again.. Failed PSU which was pretty common in these machines so I've read.. How difficult of a build would you say this would be for someone who has never attempted a build like such? I would hate to get rid of this machine but just not much a I can do with it. awesome build man I'm in awed of what you and kiwi did

Difficult is a relative term. What is difficult for one person may be simple for another. I don't know your level of experience or expertise with electronics, so I can't accurately answer your question. I started modding G4' iMacs, then moved on to G5's which are considerably more work. That said, the results are rewarding with an all-in-one retro machine running current OSX software.

I'd say a better word to describe an iMac project is 'tedious'. There is considerable time, effort and expense required, combined with the continuous risk of destroying working components if an error is made. I've done this a couple of times and its not fun to realize that a component has failed due to a careless mistake. Chalk it up to education.

If you've got the desire, time and funds to work with, perhaps give it a go. Just take care in every step, it'll likely take several months to complete if you work at it fairly consistently.

Cheers!

 

[ersterhernd]

The mod I completed utilizes an hdmi to tmds conversion. I don't have any experience with netbooks but would question if it's even possible to run an hdmi out at 1680x1050 as required by the G5 LCD.

Will the Vaio even run OSX?

This would be a first accomplished on this forum from what I can see. The NUC has so far turned our to be the only viable option to mod the G5.

It will prove to be an aggressive project to say the least to successfully implement a solution as your have proposed.

Sorry I can't help with it.

Cheers!