2 Installed memory maxxer, new SSD and reapplied thermal paste-startup?
Greetings! Just finished installed the memory maxxer kit (16 Gb) and while in there, swapped out the old 5400 rpm hd for ssd. Also removed a boatload of dust and reapplied thermal paste between heat sink and cpu after cleaning well.
On power up got the chime and thought all was well. No logo though! After about 15-10 sec fans went full bore. Still no video!
Was trying the shift-option-command-R boot to downgrade mac os to non catalina…any idea what to do next?
Thanks!
Update (12/16/2020)
here are a few pix…one after cleaning the old paste and my “thin”(?) of the new stuff. Maybe too much? Also, not sure if old paste residue along the edges is potentially a problem
Thanks again!
Update (01/02/2021)
This is a update of my second attempt to get this iMac working again.I disassembled everything once again and following @danj ‘s advice, removed my first round of thermal compound plus the residual from the initial install when the machine was mfg’d.
I did use the CRC QD Contact cleaner and it worked well! I tilted the logic board, built a “catch-pan” of sorts with a rolled up paper towel and within two or three one-second sprays, obtained a clean CPU and heat sink, including the old paste that I was unable to remove in my first attempt.
Used the following amount of thermal paste on reassembly and checked to not overflow this time…
Reassembled it and it now runs like a rocket, probably faster than when new (now using SSD with 16 Gb RAM rather than the original build with a mechanical hard drive and only 8 Gb.)!!!
Thanks for the help Dan! Next project (soon, I hope) is cleaning out dust from my mid 2011 27” iMac while upgrading CPU and video card using a pull from eBay…
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crwdns2944067:020crwdne2944067:0
Altering so much at one go is always risky!
crwdns2934271:0crwdnd2934271:0 Dan crwdne2934271:0
I figured since it isn’t too easy to get in, went all in.
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Yep! You over did the TIM!
You'll need to go back and clean the chips fully. All you need is a Pea sized dot in the middle.
What likely happened is the paste squeezed onto the carrier (green base) getting all over the SMT components and as the paste is slightly conductive you have created shorts!
I would get a loadable spray can True Power Rechargable Sprayer using 85% isopropyl alcohol to give you the needed power to clean under and around the small components.
crwdns2934271:0crwdnd2934271:0 Dan crwdne2934271:0
@danj I was wondering about that, especially while removing the old paste. How fragile are the small rows of smt components? was using a spudger to carefully carve around those areas but as the night grew late...decided to give it a go as is. There was some link to an ifixit guide about what pattern to use based on cpu. The i5 one said vertical line...tried my best to only lay down 1mm wide one. I also bought these IC graphite pads which allegedly are less likely to meander onto other components. Any experience with it?
If I were to use an old soft toothbrush and some 2-propanol and carefully brushed out the recesses...?
Again, as always, many thanks!
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@danj also wondering, I know the larger chip is the cpu but what is the other rectangular one? Assuming both need the thermal protection since under the heat sink...Thank you!
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