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.

Simple.

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.

UPDATE:
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'd have cooked itself in the summer.
So as it turns out this machine has a CPU fan, an HDD fan, an ODD fan (for the dvd burner) and.. a wimpy half inch thick snap-on heatsink the size of a business card for the Radeon X1600 with NO fan.
..
....
......
.......


No wonder Apple was underclocking the Radeon in these things. It no doubt would've burst into flame under any sort of load at full clock. They were probably running it extremely hot even underclocked. What a crappy design. 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.

2 comments:

  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 RealMacMods.com 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,
    Adam
    Real Mac Mods

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    Replies
    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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