Hi John, I gave up on “shadetree” BGA reflows years ago, but YMMV. My reflows worked for a while, then died for good. Another issue with the 2008-era iMacs is that occasionally the “coolant” (ether, I’m told) leaks out of the tubes running to and from the fins and the heat sink proper. Same problem with G4 iMacs, which also are pretty efficient little stationary Hoovers and can choke themselves to overheat death.
Jim Scott, Eureka, CA > On Mar 30, 2018, at 2:00 PM, 'John Carmonne' via iMac Group > <imaclist@googlegroups.com> wrote: > > > On Mar 30, 2018, at 10:53 AM, Jim Scott wrote: > >> >> In the case of your 2008 iMac, in addition to all of the above, the cooling >> fins of the heat sink can be clogged by dust, etc. over time as the air >> intake vents directly below the card and heat sink assembly are hoovering up >> stuff from the desktop. This leads to overheating and eventual failure of >> the BGA. Reflowing the BGA doesn’t work because by the time the problem >> shows itself, too many of the microscopic traces inside the chip have been >> damaged by arcing. That’s why a more permanent repair involves replacing the >> chip with a new one. But new chips are hard if not impossible to find, and >> my favorite eBay bad chip repair/replace guy refuses to work on those old >> iMac video cards because he can’t guarantee a reflow and he can’t obtain new >> chips that will work with the card. >> >> Been there, done that a number of times. It’s time to ewaste that iMac, in >> my experience. >> >> Jim Scott, Eureka, CA >> > > I have recently fixed a number of these iMacs may sound crazy but it worked > for me. It's free and at this point you have nothing to lose. > > Take the card off the heat sink and clean all the paste off. > Pre heat oven to 390 F (pre heat is important) > Place card on 4 small aluminum foil balls at the corners > Bake for 7 mins > Open door and let board cool don't touch it or move it. > When cool reinstall (don't forget to apply new paste). > > I have also found some with faulty fans so check the fan working before you > put it all back together. > > > > John Carmonne > Yorba Linda CA > 92886 USA > MacPro 2.66 Quad Nehalem > -- You received this message because you are a member of the iMac Group, a group for those using Apple iMacs and eMacs. The list FAQ is at http://lowendmac.com/imac/list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to imaclist@googlegroups.com To leave this group, send email to imaclist+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/imaclist --- You received this message because you are subscribed to the Google Groups "iMac Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to imaclist+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
