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Helpful Tips and Capacitor Installation Procedures

low-esr-capacitors When installing the new capacitors, the positive lead is the longer lead, and the negative lead is the shorter lead. The capacitors have a long wide line printed on the side, that matches up to the negative lead on the capacitor. This must be properly aligned with the proper holes on the power supply printed circuit board and/or the main logic card / motherboard. Make sure the capacitors are installed properly. The circuit board is typically marked with a circle of where the capacitors mount, and the positive or negative terminal is also indicated on the PCB. *Warning: If you install the capacitors in backwards, they will become damaged or explode when the unit is turned on. Making this mistake, can also damage other components in your iMac. So, pay attention, and be careful. If you are not sure, take a picture of your own power supply and/or mother board before you start working on it, so you can reference the old ones with the new ones.

I suggest you replace one capacitor at a time, so you do not mix up which one goes where. Another warning. Don’t make this mistake of installing them in the wrong location, because the power supply and/or the mother board will not function properly.

In addition, be aware that there are surface mount components on the bottom of the PCBs on both the motherboard and the powersupply units. Be careful when soldering. I suggest reading the lead-free soldering tips section carefullly. A standard 60/40 solder (though you might want to read the information first), or lead free rosin core no-clean solder may be used. Do not use acid core or acid flux with your solder. Damage to the circuit board will result if you use the wrong solder core type.

Please be aware that not all the power supplies, and to an even lesser degree, some of the motherboards can be repaired with just the capacitors being replaced. Sometimes a power supply blows something else besides the capacitors. Diodes, rectifiers, transistors, resistors, and surface mount components can go bad because of the iMac G5 capacitor failures. I will say this though, there is a high degree of success in replacing the caps on the Power Supply Units and an even higher repair success rate on replacing the caps for the MOBs to get the Apple iMacs working again. The caps on the PSUs are actually easier to unsolder and solder on the printed circuit board in comparison to the MOB caps.

After your logic card is repaired, don't forget to apply fresh, high quality heatsink compound before it is re-installed back in the chassis. This is very important for the proper cooling of the main chip, located on the bottom side of the iMac G5 logic card.

Click Apple computer repairs for more information on Apple G5 computers and how to fix them.

Here is how to identify which Apple iMac model you have.