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G4 iMac 20" Logic Board connector problem

CooperBox

CooperBox

macrumors 68000
Original poster
Nov 28, 2010
1,917
2,199
France - between Ricard & Absinthe......!
Last night I opened up the subject iMac with the intention of cleaning & re-pasting the two heat-sink locations. This machine has always performed well, but the fan has always had the annoying habit of running faster than it should, even within a minute of booting with no apps or other tasks running. A PMU reset had no effect.
It's had very little use, but I was surprised at the accumulation of dust since I last peered inside. So a good spring-clean is the order of the day, and to do a thorough job I'll remove the HD/OD assembly, clean the fan, and also completely detach the lower logic board assy from the upper dome/screen - and this is where I've run into my first problem. How to remove the black connector boot cover? (Shown below).

iMac20-ConBoot1.jpg


iMac20-ConBoot2.jpg


I imagined I could easily prise-off the black cover and then detach the connector, but the cover appears to be attached to the logic board (double-sided adhesive strip?), and so far I've not used undue force not wishing to damage anything.
To avoid any confusion, the above photos show the configuration on my 20" iMac. The earlier non-USB2 iMac models have a similar connector but in a different location (see iFixit shot below), and their instructions simply indicate, 'Gently remove the cables marked in red.'

EarlyiMacConnectLocation.jpg


Believe me, being 'gentle' for the removal of the black cover on this particular connector - doesn't appear to work!
Or am I missing something fundamentally simple?

My intention was to complete the cleaning/re-assembly last night, but due to this anomaly I'm at an impasse, and left everything dismantled and strewn across the kitchen table. So true to form, I'm in the matrimonial doghouse once again............Help!:eek:
 
Those connectors are tight and then they're broken. I have always left mine on while working inside paying attention to any stress I may be inducing to the cable/socket. I have removed and replaced the fan, ram, hdd, and thoroughly cleaned the inside of the iMac. I have broken the video socket on the board of my 15" G4 iMac and that's how I ended up with a parts machine. Good news is it forced me to look for another and I found my current 20" in my town for $40.
 
You have to pull off the black cover. It's hard to pull off of there, but it needs to be done.
 
Thanks for the feedback. I've just tried again and that cover seems to refuse to budge.
On both my photos at the base of the black cover - the light brown strip, is that an adhesive strip? Should I try and lever up from between that and the logic board, or from the strip and the cover? In other words is that strip part of the logic board, and possible damage occur if attempting to lever from it's underside. Kge420's warning of a broken video socket has made me proceed with extra caution. If finally in doubt, I'll leave the connector intact. But as it's intended to be removable I cannot help but wonder why the connector boot cover was made so difficult to remove.
 
Thanks to those who offered clarification about the adhesive pad. I decided to leave the connector intact and not remove the motherboard as I had more urgent tasks pending. But this info will be useful for future reference, and also to newbies who may wish to perform the same task.
 
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Appreciate you asking about this as was looking at this today (that was about it, my pretty much elsewhere,). Adhesive double strip sounds interesting. Makes me wonder if did have to pull it, does that adhesive strip need to be replaced. Think I'll be doing a search to see if such a thing.
 
The adhesive pad does not need to be replaced. It may still have some stickiness to it, if it does you can reattached it to the logicboard.
 
Intell said:
The adhesive pad does not need to be replaced. It may still have some stickiness to it, if it does you can reattached it to the logicboard.
Click to expand...
Ty on that, atm looks like my power unit needs replacing, gonna keep an eye out for one atm. If decide to switch out, I saw where mentioned worked around for other working on other things and sounded like didn't need to pull. Idk, this would be a first but took quick look at tape online, after seeing it, if that the tape, gonna have to have it.
 
bare spots said:
Ty on that, atm looks like my power unit needs replacing, gonna keep an eye out for one atm. If decide to switch out, I saw where mentioned worked around for other working on other things and sounded like didn't need to pull. Idk, this would be a first but took quick look at tape online, after seeing it, if that the tape, gonna have to have it.
Click to expand...

I did in fact succeed in removing that black boot cover over the logic board connector, and have done the same several times since on other G4 iMacs. On each occasion there was enough 'stickyness' to allow the boot cover to be reused.
I agree that if you have to remove/change the power supply unit you can probably get away without removing all connectors from the logic board. But be careful, if left connected you can easily strain and damage some of the connecting wires between the logic board assy and the upper dome/screen assembly.
 
Was looking on that, really on the tape but came across a heat gun or heat (which don't have and think my neighbor getting of me borrowing) loosen up the adhesive at a very low setting (and on edit-very very carefullycarefully, not mentioned sounds not needed), just don't know if how safe for components etc. Anyways ty, yes, the wires and things very tight in there. And although haven't check my video cable connection, well up the screen area, that where I take it it goes,,, all other are pointing to my PSU. And on that, know my model etc. but been a little confusing atm trying to be a 100% sure got the right replacement number. Was going back and forth if wanna spend on this as well but gonna pull PSU today and go from there plus maybe there's info on the part itself in being certain me of right one. Also Not sure how hard to repair a PSU, haven't checked, IDK, one thing at a time I guess, thank you
 
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THIS post implies that a repair of the PSU by yourself would be difficult - unless you are very specialized in those components.
Also THIS indicates that the PSU is different depending on the model. Personally I would never pay anywhere near those prices for an iMac PSU, a replacement functional iMac G4 is often far less expensive.
 
Way over my head, atm these things. From what
little I know there is a lot that goes on with them, plus sounds unique. Touched on it other night about what happens when hit the switch, very interesting. My neighbor is good with this, better than good, I'd have to catch him on really good day though if was gonna bother him with this. Haha. But yeah, came across that last night, $ for the part, did a double take. Have an idea of what I would idea of what would spend if came across one (,if/when got old one out) say its pretty be south of that. Thank you for that link BTW (,as well as code to help match up iirc in that link), much appreciated.
 
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Coop
erBox, hopefully you will see this, I wanted to see if you can offer up any help on disconnecting another wire. Decide d to go in an get the power unit out, BTW found something interesting that didn't look normal, get a picture later when get back and figure how, must been from previous owner, unrelated to my issues though. Anyways, yeah its out no issues but the wires connected to the carrier and the drive, where they plug in. Had issues getting em off and didn't want to go forcing the issue. Gotta to head out and gonna take closer look later but thought maybe some kind of trick or they are locked in somehow. If anything, be much appreciated, thank you
 
Apologize for for this in your thread with this, will start a new one, here's what mentioned above. White stuff on PSU, little bit on other half, first thought was some contact putty of some kind now not so sure. The other pic, not if gonna post well, looked like somebody threaded into the dome mounting some thing. Pretty much above where carrier drive unit. Idk, looked, don't think I did it. Thanks
 

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