On Thursday, May 14, 2015 at 4:05:32 PM UTC-5, Violet Cloud wrote: > > Hmm, well it worked once but didn't see the hard drive during > installation. > > Now it won't boot with the floppy or cd at all and will only go to the all > gray screen again. > > I would remove the logic board, remove any RAM, etc. and thoroughly wash the board. Many methods are viable. I prefer to spray boards with flux cleaner, give them a gentle scrubbing with an old tooth brush, rinse with 91% isopropyl and then rinse with distilled water. Just washing (scrubbing) with the isopropyl and skipping the flux cleaner works pretty well too.
The idea is that the surface mount electrolytic capacitors (look like tiny silver fuel storage tanks) have leaked corrosive, mildly conductive goo onto the logic board. The caps probably need to be replaced, but a servicable interim test which usually works is to thoroughly wash the board. If it works properly after that, then you've stopped any immediate corrosion, you have a (temporarily) working board, and you know that the capacitors definitely need to be replaced. The leakage from the caps is extremely hard to see. It looks a bit like old dried cola, a slight brownish discoloration and is more visible if you view the board at an oblique angle to a light source. Sometimes you'll find dust stuck in the tacky leakage adn that can make it easier to spot, but dust does not always accumulate on the leakage. Pretty much all the 840AVs out there need their capacitors replaced at this point. It's probably true of their little brothers, the 660AV, too. BTW, if the 6100 was missing its ROM it would not make a sound at boot up. If you're getting a good chord or even chimes of error/death, that means that a ROM must be present. Not really relevant any more, given how things turned out, but might be useful to know later. Also, if you start getting mysterious crashes after running for a while, on the 6100, there's a fair chance that the heat sink grease between the CPU and heat sink has turned to powder and needs to be replaced. Given time, such leakage will corrode logic board traces, vias, solder and component pins. Jeff Walther -- -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/ --- You received this message because you are subscribed to the Google Groups "Vintage Macs" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
