Over 90% of power supplies are universal in size and shape. The remaining small percentage consisting of power supplies of 1200W and more are not universal as they vary due to the main power connector. Despite not being universal, these power supplies should be compatible with the available main power connector to work efficiently.

Types Of Power Supplies
Power supply units exist in three main types: linear, switched and battery based power supply units.
Linear power supply unit is the least complicated type of power supply and it also releases the most heat.
Switched power supply unit is more intricate compared to the linear power supply unit and is also a bit cooler. However, it produces the most noise.
Battery based power supply unit is typically like the switched ones. They only differ due to the difference in components like the transformer, rectifier, filter and regulator. The difference may also come in on whether the power supply unit requires direct current or alternating current.
Are Power Supplies Compatible With All Motherboards?
Power supplies are pretty much not compatible with all motherboards. Any recent power supply unit will be compatible with any recent motherboard since they were created within the same time making their modifications similar. Power supply units that come prebuilt into a case have customized sizes usually smaller than the standard ones making them compatible with a number of motherboards.
Aftermarket power supply units are not compatible with most motherboards as they vary length. Their height and width remains the same but the length increases with increase in wattage. However, the most important connection that needs to be compatible is that of the power supply unit to the main power connector.
How Do I Choose A Power Supply?
The power supply unit you get should be able to supply power relatively higher than the collective peak of your system. A big power supply can fry the motherboard, but it cannot damage your system if the load is small. It is able to release power in required amounts only.
In the case of a PC, there is no danger in using overpowered power supply unit as it will only draw what it needs but an underpowered power supply unit may cause the system to freeze or reset. For instance if the peak power of your system is 700W a 1200W power supply unit is appropriate for use. Once you choose the right power supply unit and use it for the intended purpose it can last for up to 10years.
Also ensure the power supply unit is compatible to your main power connector as well as the motherboard or pc you are using to ensure it serves its purpose perfectly. Check the sizes and shapes before you leave the shop to know exactly what you are dealing with.
What Are The Signs Of A Bad Power Supply Unit?
1. Any power-on or system starts up failures or lockups. If you experience difficulty when starting your system once it is connected to the power supply unit then it may be faulty. These issues may come up if the unit supplies less power or is inconsistent in the power supply.
2. Spontaneous rebooting or intermittent lockups during normal operation. If your power supply gets cut short while still using your system or it reboots without your command to do so, the power supply unit may be the issue.
3. Intermittent parity check or other memory-type errors. If your system has errors like loss of data already saved in its memory the power supply unit may be faulty and hence the errors.
4. Overheating due to fan failure. Your system may abnormally get overheated due to the failure of the cooling fan. The cooling fan fails due to power inconsistencies and failure caused by a faulty unit.
5. Small brownouts that cause the system to restart. A faulty unit will release the power in inconsistent surges that cause brownouts hence restarting the system.
6. Total failure of the power supply can damage components like RAM and MOBO. Dust and overload which leads to overheating are the most common causes of power supply unit failure. The case of overheating due to overload can be sorted by upgrading the power supply unit to suit the required wattage.
How Can I Prevent A Power Supply Unit From Failing?
Use of high quality capacitors can prevent the power supply unit from failing. Buy the best quality of capacitors as recommended by a professional as it takes care of overload and overheating.
Derating is another way to prevent failure of power unit. Ensure the capacitors are as cool as possible and watch the ripple currents to make sure they are not excessively stressed.
Power supply units can be repaired in case of small issues that do not destroy all its components. It is advisable to have a certified technician do the repairs since some components may remain charged and end up causing electric shocks. Some of the repair work can be replacing capacitors as well as fuses that may have spoilt. If the technician recommends a new power supply unit, just get one as trying to keep using the faulty one may cause harm to your system and the data in it.
What Are The Signs Of Inadequate Power Supply?
Here are the signs that could indicate inadequate power supply:
System Instability
When power supplied is not enough to cater for the needs in place, the system may hang or reboot. This often causes inconsistencies in the functioning of your system.
Application Hanging
When using an application, inadequate power supply may cause it to hang or crash making it inefficient in its purpose.
Dots, Lines Or Flushes On The Screen
If you keep seeing weird unusual features like dots and lines where they are not supposed to be on your screen it could be a sign of inadequate power supply. These features come up due to inconsistent power supply or complete blackout on some components of your system.
Is It Okay To Buy A Used Power Supply Unit?
It is perfectly okay to buy a used power supply unit if it is in good condition and of high quality. The power supply unit, CPU and memory are one of the last components to wear out in a PC and can therefore be reused. It is necessary to test the unit to ascertain it is working well. The following steps can be taken to test:
1. Insert one end of the jumper into the socket of the green wire and insert the other end into the socket of any black wire.
2. Once the jumper is in place plug the cord back in. If the power supply unit is working properly, the case fans, optical drives, HDDs, and LEDs should power up and remain on. If they all fail to work, then the power supply unit cannot be reused as it is faulty. In case a faulty power supply unit is used it may cause more damage to the other components of your system.
How Do I Troubleshoot A Power Supply Unit?
Follow the steps below to troubleshoot your unit:
Step 1: Check AC Power Input
Before checking the AC power input, make sure the cord is firmly seated in the wall socket and in the power supply socket. If there is an issue, try using another cord until you are sure it is working.
Step 2: Check DC Power Connections
Ensure the motherboard and disk drive power connectors are firmly seated and making good contact. Check for loose screws and tighten them.
Step 3: Check Installed Peripherals
Remove all boards and drives and retest the system. If it works, add back the items one at a time until the system fails again. The last item added before the failure returns is likely defective.
A new as well as old power supply unit requires to be tested before use. This is done to ensure the safety of your system and its components. It is also done to ensure you have the required wattage to complete and support the task at hand. Once you realize a fault, do not ignore it. Have it fixed or replace the entire power supply unit for your own safety and that of your systems’ components.
Final Word
Most power supply units are universal apart from the few with very high wattage starting from 1200W onwards. Those that are universal are similar in size and shape. Power supply units are compatible with motherboards made within the same time hence common modifications. Overpowered and underpowered power supply units have their advantages and disadvantages.
But, overpowered is more convenient to use compared to underpowered. Being in a position to troubleshoot a power supply unit and tell how good it can work is quite advantageous. In case of repairable issues, it is best to use a qualified technician for safety and assurance of future use of the power supply unit.