|Repair/Overhaul of PowerMac G5 Liquid Cooling System and CPU Boards|
2.7 GHz Dual-CPU G5 built May 2005 - Delphi LCS
By Bill S.
Posted: July 22, 2010
(This is Page 3 of the 6 page article)
17) My first cut at cleaning the heat transfer modules off was with a vacuum cleaner. (Be careful, Vacuums can generate static electricity. A natural bristle brush and alcohol may be another option to try or perhaps a can of compressed air. (Wear safety glasses if using compressed air.)) Figures 18 and 19 show the results.
Figure 18. CPU A Heat Transfer Module Vacuumed
Figure 19. CPU B Heat Transfer Module Vacuumed
18) As you can see, vacuuming was only partly successful. I did the same thing, using a light touch with the vacuum brush, on the CPUs. Results of that are in Figures 20 and 21. Later cleaning of the heat transfer modules was done with the modules removed from the LCS.
Figure 20. CPU A Vacuumed
Figure 21. CPU B Vacuumed
19) Better, but there is bridging on CPU B (see Figure 22) that didn't let go.
Figure 22. Bridged Components on CPU B
20) Using the X-acto knife, I carefully picked out the bridges. See Figure 23. This was very tricky because the solid "salt" residue was pretty strong. (Alcohol and a stiff bristle brush may be another option to try.)
Figure 23. Bridges Removed with X-acto Knife
21) I wiped off the thermal paste from CPU A and B thermal transfer bosses with a dry cloth. Figures 24 and 25 show the OEM thermal paste below the plastic shields over the CPU chips.
Figure 24. CPU Chip A Thermal Boss Wiped Clean
Figure 25. CPU Chip B Thermal Boss Wiped Clean
22) Note that although the bosses are clean, there is thermal grease on the chip itself due to leakage through the plastic shield's cutout. Once again, though, this was apparently not affecting system operation. (most pastes are not electically conductive)
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