On Oct 24, 2019, at 3:17 PM, ihor43us via Groups.Io wrote:
The machine is from 2008, but it does all I need it to do. However, I fear that the fans are not what they used to be and probably need replacing. If I use it for any length of time it resets. If I leave it with the log on page after it resets, in a few hours it resets again. it makes a horrible noise when booting. I think it is the fan but I am open to suggestions.
In my experience Macs tend to spontaneously re-boot for one of three reasons.
1) There is too much current draw on the electrical circuit your Mac is attached to. For example, a refrigerator cycling on, or a laser printer starting up, will cause a huge draw. It might be enough to cause your Mac to have a hard crash and then re-boot.
2) Your Mac is overheating. With old Macs this might be due to the accumulation of dust inside the case insulating the heat coming from the motherboard. Or detritus in the case might be strangling your fans. Or your fans may be failing. If it is one of the first two, opening up your Mac and cleaning it out may be all that is necessary to fix things.
3) A failing power supply (flyback) or simply cold solder joints around your power supply. Often the heat cycling in your Mac expands and contracts the solder joints and causes them to eventually crack (you can feel these cracks with your fingernail - but don't try this without discharging your power supply first!) and causes a discontinuity. Touching the solder joints for the power supply with the tip of a soldering pen to re-flow the solder easily fixes cold solder joints.
___________________________________________
Randy B. Singer
Co-author of The Macintosh Bible (4th, 5th, and 6th editions)
Macintosh OS X Routine Maintenance
___________________________________________
