Sunday, September 20, 2015

Junk 2006 iMac repair - Part 2

Continued from Part 1.

I checked around for a replacement display and ended up buying a Samsung LTN170X2-L02 (datasheet) for $25 shipped. Bargain.

Another thing the UniMac adapter comes with is a "Y cable" for the inverter since the original screen has 2 CCFL lamps while most 17" laptop displays have 1. This cable simply connects the two outputs together and the combined output to a single lamp.
I'd recommend NOT trying this with any other inverters without checking datasheets and schematics unless you're trying to fry something. It's safe with the particular inverter model used in the iMacs, NOT all inverters universally.

I had several CCFL extender cables left over from a previous buy so I used two of those to make the adapter.


So then the display arrived like this:


No apparent damage though, so I hooked it all up.

It ain't pretty but it'll do

Moment of truth!

I'll be damned. First try even. Complete with perfect example of why I hate glossy screens.

Not getting any output from the firmware was a bit alarming but it does start working after a few seconds of blackness. Never ended up messing with the EDID. I'm fine with no Apple logo or boot menu on this machine since it's only ever going to run one operating system (which coincidentally isn't even Apple's) anyway.

So now came the most annoying and time-consuming part of this whole project, if you can believe that: Mounting the display.

I wanted to use the original brackets but the holes were all in the wrong place. Not only that but the right side bracket has gaps where the new display had screw holes.. Ugh..
This is starting to sound like an ad but note that the UniMac also comes with universal brackets so for $25 it's not a bad deal considering how much trouble it saves you from... Since I'm a cheapskate though, ghetto measures it is!

Yeah.. It's not pretty. The right bracket was even more of a pain as I had to add plastic L-brackets to fill the gaps in the metal.

If memory serves you need to shim the display around 6-8mms from the left side if you're using the original brackets as a base. I did 5-6 (the nut in the picture above) and it's just ever so slightly not enough. Annoying.

Especially since it's not so bad here:

But once everything was snapped back together it moved a little bit to the left. !@#!

I already added some epoxy to keep stuff from moving so I just left it as-is. It isn't something you really notice unless you know what to look for and I actually couldn't see it when I looked at it a week later.

In hindsight I probably could've just used contact glue or double-sided foam tape to glue the display directly onto the front bezel since it weighs almost nothing. Oh well..

Total cost $55 and a few hours of my time.

Not bad for a compact Core2Duo system that's still more than adequate for email and light browsing.

Still going strong in 2017. I just (4th of February) took it apart to redo the thermal paste on everything as the Radeon was idling at 71C even with the 80% underclock I had on it since day 1. I really want this to last so it had to be done since if it's 71C now It no doubt would've burst into flame under any sort of load at full clock. 
I might eventually have to buy a mobo from an integrated graphics model when (probably not if) this finally gives up the ghost. Applying some expensive "overclocker's" grease I had left from the old days helped somewhat (5-10 degC lower), I hope that buys it another few years at least.


Still going strong in 2018. I just replaced the Samsung display as the soldering of the CCFL tube failed which led to arcing which made the display's controller chip go into a reset loop or something. First time I've seen that happen. You'd think the display is completely dead and it's just the lamp arcing that's making it do that. I was feeling lazy so I very destructively removed the failed lamp and duct-taped one from the original broken LG display in it's place which worked fine as a temporary fix until I got a new one. (They're even cheaper now than when I did this project so I didn't feel like doing an LED conversion on the Samsung) Bought an AUO display instead for $20 shipped. The Samsung had better colors (IMO) but I've never had any issues with AUOs and color reproduction is not important for this machine so.. here's to hoping it lasts like the others I('ve) own(ed).
2020: CPU overheating issues. Turned out that the heatpipes in the CPU heatsink have failed. I would not have believed it if someone had told me this happened to them. I removed all the heatsink fins to confirm and neither of the heatpipes were conducting heat at all. A donor machine was purchased and the heatsink and newer looking(less browning from heat) PSU were swapped in. 
The "New" PSU promptly died 2 weeks later, old PSU swapped back in.
2021: Old PSU died. We're done with internal PSUs now, it's external PSU bodge time.

Old mac on life support
The DIN-rail thing I had lying around can do 12V/8A while the original PSU did 15.4A. I think I did some measurements with 100% CPU at some point and it should be fine but I figure the industrial thing should have good overload protection anyway. 
In the future if a working machine can't be created using remaining donor parts and stuff from my hoard then they're both going to e-waste and my father will get my old IdeaCentre which still works fine (it's original PSU also died several years ago but it was much easier to deal with since it was external from the beginning and it's 19V so it runs off any old 90W laptop charger just fine).


  1. Great job. This is actually the owner of Real Mac Mods. Believe it or not i landed on your page while researching information for another project, completely unrelated to iMacs. Anyway, i was hoping you could link off to at some point in the article in case people do want to purchase the UniMac Kit, rather than go the diy route. If not, i understand, but i would appreciate it. Thank You,
    Real Mac Mods

    1. Oh hey, thanks. No problem! I did link to your page from Part1 (the first mention of your project). Let me add one to Part2 as well.


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