Mod G4 iMac with Intel Mac mini innards?

Discussion in 'PowerPC Macs' started by casesensitive, Aug 14, 2006.

  1. cbetta macrumors regular

    Joined:
    Jul 5, 2006
    #26
    im sad to say I just sold my old iMac 15" for a Mac Mini. Mainly because my iMac didnt have any USB2, and was to big to bring with me when I move to London.
     
  2. pmackin macrumors member

    pmackin

    Joined:
    Oct 25, 2004
    Location:
    Chennai , India
    #27
    inverter ??

    I've looking at the manuals .. on the flat panel imac the lcd connects to a inver ter .. which connects to the lcd .
    now my question is , could there be a way to get a cable from the dvi port of the mini and run it to the inverter ?
    forget about routing the cable for now , but will this work electrically speaking.
     

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  3. ericarthur macrumors newbie

    Joined:
    Sep 30, 2006
    #28
    does anyone have the service manual for the iMac 15"? I saw it once and there was a wiring guide for the video wire. That would make a DVI adaptor much easier.
     
  4. Stadsport macrumors regular

    Joined:
    Nov 9, 2006
    #29
    The inverter is to power the flourescent lamp (backlight). DVI is the signal.
     
  5. Sam0r macrumors regular

    Joined:
    Jun 15, 2005
    Location:
    Birmingham, UK
    #30
    Forget about power for now, thats a 10 second job, especially since the inverter is already in the display. It'll just need DC power (Probably 12v) and the correct DVI signal.

    You say there are 12 pins?

    Can I get a picture of the connector?
     
  6. GrimmMac macrumors newbie

    Joined:
    Jan 27, 2007
    #31
    Well, something died inside of my 17" iLamp G4. When you push the power button absolutely nothing happens. A few hours later and I've got the thing completely dismantled and found this thread via google :)

    I am hoping to be able to use the LCD as the primay display for my wife's G5 tower or a secondary monitor on my MacPro tower.

    I have taken several photos of the connectors in question and hopefully someone a little more savvy than me can help us all solve the problem of driving one of these things with a VGA or DVI output from a computer.

    I will see about posting those photos...

    There are four main cables that exit the metal support arm. They are clearly in pairs, two apparently dealing with power. These two cables come from the motherboard via a 16 pin connector out to the fan, speaker and then into the LCD as well. One of the wires is clearly labeled "INVERTER CABLE"

    The other pair is what I believe to be the video signal heading into the LCD. One cable is light gray, the other black. They come out of the support arm separatley but then terminate in a single connector which was attached to the motherboard.

    It has 21 pins in two rows. One row with 11 the other with 10. The two cables are taped together with a label which reads 620-2305. The connector itself has the word "Foxconn" stamped into it on both sides. The metal bracket on the connector is just over 5/8" wide; the 11 pin side is 9/16"; the 10 pin side is 1/2". I hope this is helpful to someone :)

    VideoConnector.jpg
     
  7. Sam0r macrumors regular

    Joined:
    Jun 15, 2005
    Location:
    Birmingham, UK
    #32
    Thats going to be VGA/DVI then. It'll be DVI though.

    Any pictures of the wires coming out of that connection? I need the colours of the wires, each individual wire that is. All 21.
     
  8. GrimmMac macrumors newbie

    Joined:
    Jan 27, 2007
    #33
    If you want to see what the wires for each of the 21 pins look like, I have three choices:

    1) Hack the two cables in half to expose the individual wires within each.

    2) Attempt to expose the wires coming out of that connector by removing the plastic jacket near the connector itself.

    3) Disassemble the LCD enclosure to see if the wires might be exposed on the other end.

    I'm not particularly fond of 1, but that is surely the easiest way to do it.
    Option 2 is likely to be the most reversible of the three options, but may or may not work.
    Opening up the LCD enclosure is a gamble on whether the wires are even exposed.
     
  9. Sam0r macrumors regular

    Joined:
    Jun 15, 2005
    Location:
    Birmingham, UK
    #34
    Option 2 would be fine.

    Although if you want to fit the LCD to a Mini, you'll have to hack apart the cable anyway, although I don't know if thats your intention or not.
     
  10. GrimmMac macrumors newbie

    Joined:
    Jan 27, 2007
    #35
    My particular intent is to attempt to attach it to the DVI port on my PowerMac G5 or else MacPro Tower. I will have to take pictures and post them tomorrow. I should have been in bed 3 hours ago :D
     
  11. fuyutsuki macrumors newbie

    fuyutsuki

    Joined:
    May 8, 2006
    Location:
    Edinburgh, Scotland
    #36
    I have a busted 800MHz Superdrive 15" iMac G4 I picked up for free recently and can verify what's just been said about the wiring. (Mine is DOA so I suspect the power supply and/or motherboard.)

    The crucial connector is the silver coloured one photographed above, which is actually quite small and has 21 pins, clipping into its mate on the motherboard with a satisfying 'click'. There is also the second cable talked about which seems to be for power to the LCD and other devices along the way.

    Now I also happen to have the service manual, and have just been Googling for data. Here's some of what I've come up with:

    I don't know much about internal connections to digital displays, but which is more likely: this crucial 21 pin connector is VGA based like the secondary output or is something exotic linked to this specific screen?

    As said by Stadsport on the other thread:
    Damn! Sounds like it may be a better idea to remove the LCD and replace it with an identical sized (and maybe higher res) new one whose inputs are known.

    Anyway, since I've been elbow deep inside my broken iMac several times I'd like to add the following notes:

    • The iMac uses a full size parallel ATA hard drive and optical drive, which are master and slave on its single IDE channel.
    • The hard drive and power supply share space right at the top of the dome, closest to the neck.
    • Fitting a Mac Mini inside is quite possible on first glance, but NO WAY with a full size optical drive at the same time, however a 3.5" hard drive is probably fine.
    • Inside the iMac case is a metal structure called the Faraday Cage which basically makes for a thicker shell, reducing the space from what you'd think
    • The drive slot at the front is very easily made to open, so you don't need a perfect match to make it work, however a slot drive would need to be "helped" whenever you want to open the door without a disc already in the machine!
    • Intel Mac Mini's have a large power supply brick which takes the same plug as the iMac but is too big to fit inside the case as well as a Mini, so an external cord trick would need to be used.

    Anyway, keep this project alive as I know there are many Sunflower Mac lovers out there, including latecomers like me, who want Intel power in a design classic case. May the hack be with you!
     
  12. tuc macrumors 6502

    Joined:
    Aug 25, 2003
    #37
    This is pure speculation, but I would expect the signals between the iMac G4 mainboard and its LCD display are pretty much the same as the signals between a powerbook's mainboard and its LCD display.

    Why would they bother putting DVI (or VGA) decoding circuitry on the LCD end of the arm if they didn't need to?
     
  13. fuyutsuki macrumors newbie

    fuyutsuki

    Joined:
    May 8, 2006
    Location:
    Edinburgh, Scotland
    #38
    This sounds reasonable, so what's it like in the laptops then? Is there some sort of standard that raw data to TFT's is sent in? Is it something we could emulate?

    My feeling is that if it's not easily done, it might be best to get hold of an equally sized standalone display (with DVI / VGA connector) and hack that into the Mac instead .. as the iMac's TFT is indeed removable with a little care. Whatever else goes in would need to match the iMac head quite nicely. But then again, it could also be of a higher pixel resolution than the iMac's lowly res. Interesting idea if it's do-able. Especially as a normal screen power supply should be able to fit inside the iMac base quite easily so long as it's not humongous ... especially if we're talking about turning the iMac into a display rather than a display with a Man Mini included in the package!
     
  14. GrimmMac macrumors newbie

    Joined:
    Jan 27, 2007
    #39
    Here is a shot of all the cables coming from the metal support arm.
    [​IMG]

    This is a picture of the exposed wires as they go into the connector. The colors are not completely true to life due to the lighting. The colors are as follows from top to bottom:
    (Small wires) Yellow, Green, Blue, Purple, Red, Black, White, Gray, Orange
    (Large Wires) Green, Red, Brown, Blue
    [​IMG]
     

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  15. fuyutsuki macrumors newbie

    fuyutsuki

    Joined:
    May 8, 2006
    Location:
    Edinburgh, Scotland
    #40
    Nice work. We'll have to see if anyone can tell us what they mean!

    Hmm.... this is the most detailed snip from another thread:

    The Wikipedia turfs this up under LDVS...

    http://www.national.com/nationaledge/may01/lvds.html
    [​IMG]

    I'm thinking ... ¿ay que lastima?
     
  16. xyian macrumors 6502

    xyian

    Joined:
    May 24, 2004
    Location:
    PDX
    #41
    I really hope you all keep this project going strong!
    I'm sorry I can't contribute to the cause here but I haven't
    done any soldering since high school.
    If you do get it up and running though, I will strongly consider
    buying an old 20" iMac and attempting this(after much solder
    practice, of course....)
    Cheers!
     
  17. fuyutsuki macrumors newbie

    fuyutsuki

    Joined:
    May 8, 2006
    Location:
    Edinburgh, Scotland
    #42
    Is it just me, or do the "18+3" wires going into the "TCON" on that diagram above sound a lot like the 21 pins on the video jack? ;)

    There's also an 18+3 arrangement on the other side of the picture, right into the VGA (graphics card, which we know is on the iMac motherboard), but that side needs a separate clock signal.

    In other news, no luck picking up a generic 15" TFT here to pursue the alternative.
     
  18. R0ck1t macrumors member

    R0ck1t

    Joined:
    Feb 6, 2007
    Location:
    England
    #43
    :) Excellent that someone else has had this brilliant Idea

    I also own the iMac G4 (But 17" as no one seems to on this thread), I have opened it and had a look but have limited knowledge of computer functions.
    I'll soon have Electronics & I.T GCSEs and would gladly help if anyone can think of a way I can.
    P.S
    If anyone knows of a way to upgrade the USB1.1 to USB2 or have an external hub I would be grateful if you shared this wisdom.
    Cheers.
     
  19. gramorris macrumors newbie

    Joined:
    Feb 9, 2007
    #44
    I've got a 17in which I can't bring myself to dump yet and I've been furiously researching hooking up a mini to the display. This thread seems like the best hope so far although I can't say I have any experience doing this but I will help if I can.
     
  20. dukeman macrumors member

    Joined:
    Feb 5, 2007
    #45
    You need a controller between the LCD and the Mini VGA out. There is no way to directly connect the wires from the LCD to the Mini. The imac has this "controller" built into the logic board, as do most laptops. You can buy a controller "http://store.earthlcd.com/LCD-Products/Analog-VGA-Controller-Cards"
    but they can get pricey. Second option might be to take apart a stand alone LCD monitor and borrow some parts, just watch the power outputs / inputs, would be easy to fry your good LCD Panel.
     
  21. fuyutsuki macrumors newbie

    fuyutsuki

    Joined:
    May 8, 2006
    Location:
    Edinburgh, Scotland
    #46
    Nice link. This looks promising:

    Could someone in the US give them a call? As in ask if they know the iMac G4 and whether it's 15, 17 or 20" TFT is compatible with their board. I don't fancy crossing the Atlantic with my phone company, this is what the internet's for after all! ;)
     
  22. Maxwell Smart macrumors 6502a

    Maxwell Smart

    Joined:
    Jan 29, 2006
    #47
    This discussion looks promising. An intel mini inside an iMac G4 would be so cool, not only because of the obvious increase in performance and new RAM ceiling (of 3GB) but also because you could probably get a full size 3.5" hard drive inside, and can easily upgrade the mini's processor because it's socketed. Good Luck with this, unfortunately I don't have an iMac G4 otherwise I would try to contribute.
     
  23. dukeman macrumors member

    Joined:
    Feb 5, 2007
    #48
    Send them an email with the whitepages for the imac lcd in question and they will tell you. I havent had time to hunt down the whitepages but got an email back asking for them about an hour after i emailed sales.
     
  24. tuc macrumors 6502

    Joined:
    Aug 25, 2003
    #49
    LDVS vs. TMDS

    From what I can tell (and I know nothing) it probably does use LDVS (FPD-Link/LDI), but it could possibly use TMDS (DVI/HMDI/???). Some graphics chips have built-in TMDS senders, so I suppose Apple could have used it in the g4 imac if they had wanted to for some reason.

    Even if we somehow determine it uses FPD-Link, there are 18-, 24-, and 48-bit senders and receivers. I would guess that Apple would use 24-bit, but what do I know? I guess we could look at the markings on the chips and see if there is anything to be discovered. For example, if we see a chip marked DS90CF384A on the display end of the arm, then we know it's 24-bit LVDI. (Though I guess it is possible that the sender was 18-bit instead.)

    The thing is, there are sure to be people out there who know exactly what the g4 imac (and other iMac/eMac models) uses, if we could only find them.
     
  25. The Senator macrumors regular

    The Senator

    Joined:
    Feb 18, 2006
    Location:
    Virginia
    #50
    why not just rip everything out of an intel imac and put in all in the imac g4?
     

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