iMac G4 mod, looking for input and ideas!

Discussion in 'PowerPC Macs' started by chickenninja, Apr 10, 2016.

  1. chickenninja macrumors 6502

    chickenninja

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    #1
    So I got an old imac G4 locally for a mere $15 I'm looking to maximize it's potential with a 128gb SSD, maxed ram ultra quiet fans, and mini heatsinks on every inch of black, square, lukewarm, surface. I'm open to ideas ;)

    Here are some tasty links of the things I have planned for it.

    I'm leaning towards this fan as a stock 92mm fan replacement. Silence is the top priority of this build!
    http://www.silverstonetek.com/product.php?pid=519&area=en

    or try and fit in a 120mm or 140mm nb eloop fan either under the DVD drive to blow across the mobo or on top of the DVD drive in the space created by having a smaller SSD. I love the fans design almost as much as the ImacG4 so I would like to have it worked in there somehow.
    http://www.blacknoise.com/site/en/products/noiseblocker-it-fans/nb-eloop-series/120x120x25mm.php
    http://www.blacknoise.com/site/en/products/noiseblocker-it-fans/nb-eloop-series/140x140x29mm.php
    (25mm, 29mm)

    I'm even considering a thin 12mm fan made by Scythe, I'm thinking it would be the best shot of fitting a fan between the DVD drive and the mobo to cool the graphics card. It would be especially cool if I put it on a fan controller knobb which I could have poking out of the modem port.
    http://www.scytheus.com/product/kaze-jyu-slim-100mm/

    I would love to get a smaller DVD drive that could still open the door, I would really appreciate any leads on that. I would also love to know how big of a heatsink I will need for the northbridge, and other little chips scattered around, I have some ramsinks already but I would like to get exact sizes before cracking it open.

    I'm debating whether I should put a bluetooth module in it, as I have a iomega USB bluettooth adapter and I was wondering which bluetooth solution would have the system running faster. My current keyboard/mouse use their own dongle, but they are lame so I want to get a more modern apple bluetooth keyboard for it. What do you all think would be faster, using a USB iomega bluetooth adapter, or installing a G5 bluetooth module.

    I'm even thinking of building a dust filtering platform for the iMacG4 to rest in. Feel free to throw out any cool ideas you have for the mod.

    If there is any one single thing I would like to get, it would be a smaller DVD drive that can still tongue open the door.
    --- Post Merged, Apr 10, 2016 ---
    I forgot to mention, It's a 20" ;)
     
  2. mode11, Apr 11, 2016
    Last edited: Apr 11, 2016

    mode11 macrumors member

    mode11

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    #2
    Cool computer, I've got one of those too. I wouldn't bother with additional heatsinks, unless you are just looking for something to do. I don't know why you would need them, as you can't really overclock the iMac.

    Fitting a replacement 92mm fan would be by far the easiest option. You can go quieter I'm sure, but make sure the CFM is equivalent. The stock fan has an unusual design that has cut-outs in the sides of the frame (I think Thermaltake used to make them). I'm sure a regular fan would work fine though. Using a more compact DVD drive would help general ventilation. You may want to check compatibility though - there may be caveats to using non-Apple firmware drives (especially for burning), depending on OS.

    An SSD would need converting to PATA. Perhaps use a PATA to mSATA adapter and an mSATA SSD. Then a 2.5" to 3.5" adapter.

    As for bluetooth, there was a specific D-Link USB dongle that Apple actually provided a custom firmware updater for, before Macs generally had BT as standard. The issue with regular BT adapters is that when the iMac goes to sleep, the USB port is powered down, so you can't use a connected keyboard / mouse to wake the Mac. The special firmware solves this. I have one on my G4 iMac, used with an older 3-battery aluminium keyboard and a wireless Mighty Mouse. Works perfectly.

    Retrospectively installing internal BT seems like a lot of work, involving major disassembly. See iFixit. The inside of the iMac is metal (a lead alloy), blocking radio, so the antennas need to go between this and the outer shell, in special cut-outs. You'd probably have to get another G4 iMac just get the parts anyway.

    Word of warning: when you have the iMac shell open, be VERY careful not to damage the internal video cable. It clips onto the side of the drive cage. If you unclip it, make sure you clip it back in before closing up the case, or you risk pinching it between the case halves (this will permanently render the display unusable).
     
  3. chickenninja thread starter macrumors 6502

    chickenninja

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    #3
    We'll that explains why I can't get it to wake from the keyboard lol. I'm going to have to experiment and see if a powered USB hub can forward a wake signal, but I guess if "nobody is home" in USB land, it wouldn't matter anyway. You know I haven't been able to wake it from the power button either, it starts up but hangs with a black screen. I'll have to diagnose that kind of stuff once I get a new Pram battery in there, the current boot time is like 15 minutes! I really appreciate your reply, it was really good! I'm trying to get a IDE based SSD, there are a few on Ebay by Kingspec, but for $90 I may end up getting a converter like you described, as the SATA drives+ a converter are actually cheaper than the IDE/PATA drives. Do you forsee any software side issues with using a converter? I don't want to give the mac anything else to think about.

    And YES!!!! I am all about those heatsinks lol! I've learned in the world of Audio Electronics that when components get hot, their electrical resistance increases, which causes even more electricity to be converted to heat in the struggle through that higher resistance. It's a total feedback loop, so under this assumption I freely indulge myself in many a heatsink, on as many completely irrelevant system components as possible lol My thoughts tend to go to whether the heatsinks will raise the ambient temperature in the case, or whether they keep the components so cool that they end up producing less heat due to lower resistance, leading to a cooler case. I think heat sinking everything would also help reduce the severity of temperature spikes, and lead to higher performance during extended use. If I do make a dust filtering base for this iMacG4, it will also have a giant heatsink to help keep the bottom plate cool ;) which hopefully won't make the wifi too wonky.
    --- Post Merged, Apr 11, 2016 ---
    When you say "can't really" what is the constraint that comes to mind?
     
  4. mode11 macrumors member

    mode11

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    #4
    When I say "can't really", I mean it's almost certainly impossible, though perhaps there's someone, somewhere who has managed to overclock the bus or change the CPU's multiplier. G4's aren't known for their overclocking potential, though, and doing so generates more heat in any case.

    Don't bother with the USB hub - it won't work. I think the issue isn't that there's no 5V power at the port when asleep (or else my dongle wouldn't work), more that the BT dongle goes into a low power state. The special firmware prevents this. There is only one dongle that will work like this - the D-Link DBT-120. You may find one on eBay - though they're old (2002). There may be different revisions - I can help further if you're thinking of doing this.

    The iMac should boot in less than a minute. Perhaps the HD is faulty? Have you tried a fresh install of Tiger or Leopard? If the DVD drive doesn't work, it's almost always the lens - clean with rubbing alcohol (disassembly required). Or install via FireWire target disk mode from another PPC Mac.

    You can reset the PRAM without opening the machine. A fresh battery is always good, but may not be necessary. If you open the case, you'll need to apply fresh thermal paste to the relevant spots inside.

    Forget IDE SSDs. They're overpriced, slow and inconvenient for other uses later. Converters should be transparent to the computer (i.e. the Mac isn't aware of it being there) and will just work. I would check the forum for compatibility with a specific model, if possible, as there's always the potential for odd issues (as with all computer upgrades). Or just buy one that other people have had success with (on any Mac, shouldn't need to be an iMac G4 specifically).

    Seriously, forget about the heatsinks. Whatever the theory, how are you going to tell if they are of any benefit? Apple designed the iMac to work at its full speed indefinitely - you won't see any speed increase. Also, I'm not sure if you have much experience with G4 CPUs, but set you expectations fairly low. With the right browser (WebKit) and various plugins / tweaks you can browse the web at a sedate pace. Or play older games like Quake 3. But don't expect to be blown away.
     
  5. val1984 macrumors member

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    Jan 26, 2015
    #5
    It's definitely possible but it requires soldering.
     
  6. mode11 macrumors member

    mode11

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    #6
    Thought someone might have done. It's worth noting though that even a minor overclock, from 1250MHz to 1333MHz, wasn't stable. They only managed to downclock to 1000MHz, which is a proof of concept but kind of pointless.
     
  7. val1984 macrumors member

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    Jan 26, 2015
    #7
    Some CPUs fare better at overclocking than others so it's definitely not surprising that one is overclockable (1 -> 1.25GHz) while the other is not at all.
     
  8. chickenninja, Apr 12, 2016
    Last edited: Apr 12, 2016

    chickenninja thread starter macrumors 6502

    chickenninja

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    #8
    Thanks for clarifying :D I just realized you're from London and that "really" probably has a nuanced difference from here to there (in the states, UTAH). ha ha ha
    PS. Love that Gherkin!
    --- Post Merged, Apr 12, 2016 ---
    I'm thinking I'll be doing this, I've got a keyspan remote with a sleep button on it, it uses a dongle and interfaces nicely with Frontrow, I'm primarily going to use the iMac G4 to play yoga DVDs that I backup onto the SSD. With a wakeable USB state I can use that one little remote to wake it up, navigate front row, do some yoga, and put it back to sleep. All without ever touching a keybaord or mouse. BOOYAH!
    --- Post Merged, Apr 12, 2016 ---
    I attempted to reset it with the commands during startup, heard the tone and felt successful, but it didn't make any difference, it's a fresh Leopard install, but I have some 3rd party USB stuff that may be confusing it on startup, I've got a tv tuner, my keyspan remote, a wireless-N USB adapter, and of course my keyboard/mouse dongle. I don't usually have the wireless-N adapter on there because it launches on start and slows everything down. I also have my speakers connected, so Imagine the Pram may be searching for these missing devices. The HDD is also on it's last legs so that may explain it, It seems to take longer booting now that I upped it to leopard, but I also strained the harddisk by reformatting it twice soo it could be allot of things, but from all my reading it seems like the Pram battery is past it's lifespan and is known to cause these kind of hangups, so that's where I'd put my bets.
    --- Post Merged, Apr 12, 2016 ---
    OOOh! would you happen to know if the video-ram chips could be upgraded? I'm not afraid of ambitiously micro scale soldering.
    --- Post Merged, Apr 12, 2016 ---
    DOH!

    http://giphy.com/gifs/TwtXMS5EnKDBK
     
  9. JRDN, Apr 13, 2016
    Last edited: Apr 13, 2016

    JRDN macrumors member

    JRDN

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    Oct 24, 2015
    #9
    I really love your ambition with this. I too share a similar knack and desire for modifying stock apple hardware for the max potential.

    I'm now looking into a fan replacement for my g4 imacs. Mine aren't particularly noisy but a fresh fan would be great. Picked up a new 20" one a few days ago!

    In regards to that, I would look into another fan that is not a sleeve bearing fan. Sleeve bearing fans don't have as long of a lifespan when mounted horizontally. The fan you linked from silverstone is a sleeve bearing.

    They are a simple design with essentially a rod in a sleeve casing with some lubricant. If mounted horizontally the oil eventually leaks and that causes the fan to fail/get rather loud

    I'm personally looking into the Arctic 92mm fans, Black/white, Fluid Dynamic bearing
    Also, the Noctua Redux 92mm fans. Great build quality and warranty and quiet!. (just double the price...)

    I use an IOGear bluetooth adapter that works OOB. I haven't noticed that I couldn't wake my G4 with my mouse, I'm typically a spacebar-masher when I want to wake it up. I'm now looking into the aforementioned bluetooth adapter.


    One other add that you can do is to upgrade the internal RAM module to a 1GB dimm. There's a bottom laptop-sized DIMM in there that is user-upgradeable to 1gb. The other module inside (a measly 256mb) is a desktop sized stick and can be upgraded to 1gb also. My 20" now has 2GB of useable RAM vs the 1GB Apple states is the "max."

    For more info on the Ram upgrade


    As for the heatsinks. I too wouldn't bother with it. I think shooting for some high quality thermal paste (I use MX-4) for the already existing heatsinks would be of great benefit
     
  10. mode11, Apr 13, 2016
    Last edited: Apr 13, 2016

    mode11 macrumors member

    mode11

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    #10
    Slower versions of a particular chip model usually have more chance of overclocking. The 1GHz iMac may have actually used down-clocked 1.25GHz CPUs, either to reduce power consumption / heat, or just to create a lower spec model in the range. There are also yield issues, of course. But most of these 1.25 chips seem to hit a wall at 1.3GHz.
     
  11. mode11 macrumors member

    mode11

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    #11
    Even if you did (what a job!), they will run at the same speed unless you can enter a new VRAM frequency into the graphics card firmware. This may be a separate chip, or integrated into the iMac's overall firmware (I have no idea). You would need to investigate whether it is possible to increase the VRAM speed of an iMac G4 with a utility / Open Firmware commands. If so, there may be a use for your beloved heatsinks after all, if you can overclock the VRAM a little. Though I wouldn't expect to see any appreciable real-world benefit.
     
  12. fhall1 macrumors 68040

    fhall1

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  13. davidg4781 macrumors 68000

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    Alice, TX
    #13
    Have you cracked this one, or any iMac, open yet? I purchased a 20" iMac G4 and wifi and BT were not working. Once I opened it up I found the previous owner had opened it and crushed both antenna wires virtually in half.

    I purchased a wifi replacement online. And crushed that one (I didn't realize I'd have to rout it a certain way since the previous one wasn't). I have not been able to find a BT one. I almost spent way too much on one once and my order was canceled since they were OOS.

    Your's might have the antenna already and may just need to have the BT card added in the bottom user accessible part. Those cards are relatively inexpensive.
     
  14. chickenninja thread starter macrumors 6502

    chickenninja

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    #14
    The wifi is installed already, looks OEM, I have had the bottom plate off tonight to install new ram, and I got a good look at the antenna cable running out of it, with a neat piece of circular tape holding it in place. Other than the bottom plate I dont think it has ever been opened any further. Does the wifi antenna being there already mean that I could just plug in the bluetooth module on the topside of the logic board? or would I have to monkey with that antenna? or perhaps a second antenna?
     
  15. davidg4781 macrumors 68000

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    #15
    There are two antenna. One for the Bluetooth and one for WIFI. If you just opened the first bottom plate you should see where the Bluetooth card goes and the antenna lead, and the SO-DIMM socket. I'm sure they were pre-made for BT to easily add the card. You shouldn't have to mess with any antenna wires, unless they have been previously removed.
     
  16. chickenninja thread starter macrumors 6502

    chickenninja

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    #16
    Yeah I have having second thoughts about that fan for that exact reason, I also find the triangular geometry antithetical to the G4 design. I agree fully that Fluid Dyanmic bearings are the way to go, but the statline of that fan was really sexy in terms of it's low DB, and the fact that it's all white. I'm glad you mentioned the leaking oil when in the horizontal position, I was not aware of that, and it's a game changer. Maybe Noiseblocker will come out with 92mm model of the E-loop. That would be perfect. I've also been considering the silenx 92mm fan. http://silenx.com/quiet.fans.asp?sku=efx-09-12 but so far I have only been able to find them in yellow, although it appears they have white.
    --- Post Merged, Apr 18, 2016 ---
    Checkout what I've got coming in the mail ;D is that a sexy heatspreader or what! It's pc3200 instead of pc2700 which I have read works just fine in imac G4s, as they just recognize it as if it was pc2700, but since it's next generation it must be better in nuanced ways right! Most notably since it was designed for a clockspeed of 400mz instead 333mhz, I feel it will have more headroom and advantages in slightly more modern design improvements such as thermal dissipation that allows it to stably run at the hotter, faster, 400mhz. I know the ramm will still only run at 333, in tandem with the ram controller clock speed, but if the system maxes out, (which it will totally will under normal 2016 use) It's nice to know that at least one bottleneck across the 333 interchange is designed to run higher than it's clocked. The only downside I could see would be harmonic issues between differences in tuning frequency.
     
  17. JRDN macrumors member

    JRDN

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    #17

    I have some interesting findings to share with you regarding the fan replacement.

    I have two 20" iMac G4s. One of them has the stock fan and the other I replaced with a Noctua Redux 1600.

    When I was replacing it I noticed it's a very specific design that you can't buy. The blades have been rotated 180 degrees and the air flows the opposite way from a standard case fan. I have the white apple G4 fan next to a standard 92mm fan to highlight the differences in blade design.

    After I replaced the fan I put everything back the way it was, reapplied thermal paste to the heatsink spots and reassembled.

    Note that there's also vents in the side of the fan housing. From testing these two iMacs side by side when left to idle the one that has the new fan is blazingly hot on the bottom. Hot enough to warp and slightly melt my plastic swivel chair mat. The outer shell is definitely warmer than the stock fan configuration too. These systems are identical.

    I used a thermal gun pointed at the outer shell just under the apple logo to get a temp reading. The new fan one was 29C and the stock fan was 20C

    The bottom metal portion is the real trouble here...

    New fan one: 32.5
    Stock: 23.2

    The one with the new fan is nearly 10 degrees C hotter! (90.5 degrees Fahrenheit VS 73F)

    I have a very good feeling that those side vents really do help tremendously by pulling air from the bottom holes and up the sides, through the PSU units, and out the top. You can see in the last image how those side vents would come into play here. With a fan replacement you really can't mimic this cooling. I also have a feeling that the HDD located right underneath the fan really inhibits the flow of the new fan. If it was a 2.5" drive (I'm planning on upgrading to that) I think air flow would be better.

    For my cooling differences I am going to ditch the new fan replacement and go back to the stock fan.....which interestingly enough is a sleeve bearing! I'm hoping to see those temps drop back down after the stock fan is back in. I never noticed how how it was before I replaced it though.

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
  18. mode11, Apr 19, 2016
    Last edited: Apr 19, 2016

    mode11 macrumors member

    mode11

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    #18
    The inverted fan design is probably to allow the sleeve bearing design to run horizontally. In a conventional design, the lubricating oil may run down into the end cap eventually.

    The slots in the side are probably to suck in hot air that would otherwise pool in the top of the dome, around the fan. I think Thermaltake did do one like this, but they'd be hard to find now. Perhaps an open frame design - check out the Arctic F9 Pro. Even blows the right way, and is white. Might need to look at the mountings though.
     
  19. chickenninja thread starter macrumors 6502

    chickenninja

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    #19
    That is a surprisingly steep contrast! I would have expected maybe 4 degrees max, but 10! that's profound! Like mode11 commented, I also have had suspicions that the slits in the fan were for drawing in the air pooling at the top around the power supply. But I have a few other thoughts too, one would be that the thermal paste isn't doing the job as it did before, and the other is the amount of pressure the fan can produce. Most fans only include their CFM rating, while the static pressure is just as important, usually you can tell by the shape and spacing of the blades whether the fan is optimized for speed or for torque. The other obvious reason is that the fan is black instead of white ;P . I tried to find my thermometer so I could get you some baseline measurements from my unit but alas I couldn't find it. What I really want to know is how much space is actually there between the power supply and the amplifier? 100mm 110mm? 120mm I'm thinking of getting a larger fan and dremeling out the frame, maybe even mounting it a little lower in the space previously occupied by the HDD. A typical fan's frame is about 5mm thick, so two sides of that would take a 92mm fan into enough space for a freewheeling 100mm fan, or maybe even the holy grail of being able to access high quality fans for the 120mm fan market. Particularly the oh soo sexy Noise Blocker E-loop. Do you have calipers where you could get a measurement for me?
    --- Post Merged, Apr 23, 2016 ---
    Dude I think you're on pointe on every single one of those hypothesis. That F9 pro has shown up in the parameteres of my discerning searches too, it may just end being the answer.
     
  20. JRDN, Apr 25, 2016
    Last edited: Apr 25, 2016

    JRDN macrumors member

    JRDN

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    #20

    I would still stick with the stock fan. I swapped it back into my g4 and the bottom is still warm but a normal warm not a blazingly hot surface. I'm curious how the arctic fan would do. Though it's shroud is different and may not work well with the existing brackets for mounting.

    I held up a 120mm fan to the opening and it's just 1/4" too long to fit in between the power supplys. I would stick with a 92mm fan with the ability to draw air from the dome and not mess around with it

    I did find these though:
    http://www.newegg.com/Product/Product.aspx?Item=N82E16835709017

    http://www.ebay.com/itm/Thermaltake...004671?hash=item3d1406f27f:g:9LwAAOSw~bFWHbsB

    The Thermaltake Silent Cat fan is the fan that was mentioned. 120mm is available. I didn't have luck with a 92mm

    Another option: http://shoppingshopping.com.au/Case...ter-UFO-Fan-Silver-UV-A2219-p2p-15296-77.aspx

    I should have considered the SP fs AF fans. It seems the 92mm fan I got was more suitable for airflow because of how much space there is between the fins.
     
  21. mduser63 macrumors 68040

    mduser63

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    #21
    I'm curious to know if you ever ended up modding your iMac, chickenninja. I picked up a 20" recently too, and would like to replace the fan while I'm inside it installing an SSD, more RAM, etc. I'm leaning toward the ARCTIC F9 PRO and am wondering if you (or anyone else) had good luck with it, or if you found another, better fan.
     
  22. mode11 macrumors member

    mode11

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