When the computer struggles to turn on or takes too long to start and when it makes too much noise, it may be that the problem concerns the PC power supply (also called PSU or Power Supply Unit ), which is perhaps old and not very efficient or underpowered compared to the computer hardware.
Switching power supplies is also a way to save energy consumed by a desktop PC, because newer PSU units are optimized to consume less energy.
For example, I have had the same PC for almost 10 years, but recently I added RAM, an SSD unit, a dedicated video card and a fan, greatly modifying the initial configuration (from which in practice only the motherboard and CPU are left) .
As a result of these changes, every time I turned on the computer I had to wait a time varying from 10 seconds to 10 minutes before the screen turned on and the BIOS loaded, long before then loading Windows.
The reason for this switch-on delay could be in the damaged motherboard, in one of the RAM memory cards, or in the power supply (500 W) that does not make it.
I then opened the case of my desktop PC and detached the extra fan and, alternatively, the two older banks of RAM noting that one of the two was damaged.
Replaced the damaged RAM, I noticed that the PC started up fast only if I unplugged the fan and I understood therefore that, at 90%, the problem was in the power supply.
Replacing the PC power supply, however, may seem something very complicated if you look at how many cables and connectors it is connected to, but there is no need to be afraid, because it is all a job to unplug and reattach them, without the possibility of make a mistake.
READ ALSO: What symptoms if the PC power supply has failed or is about to break "> buy a power supply with adequate power for the PC, it is really worth going to Amazon because the prices are very good.
Among the different PSU models on sale, the most balanced in terms of price and performance is that of Corsair, available with various power classes, for ATX houses (the large case).
In my case, since I have three discs and a level video card, I chose the 650W one.
In a normal PC, the 550 W one (which is the best-selling one) may also suffice, while if you want a very quiet one to power an economic PC you can choose the 350 W one.
Keep in mind that the Corsair that I also bought is a non-modular power supply, that is, with all the fixed cables attached.
This type of power supply is fine if you have an ATX-type thick case with space inside.
If you are using a small case, Micro ATX or Mini ATX, a modular power supply is convenient, which allows you to eliminate cables that are not used.
The modular power supply therefore allows to occupy less space inside the PC, to leave more air passage and decrease the accumulation of dust.
To change the power supply, therefore, you must first unscrew the screws outside the case in the rear (in practice around the space where there is a switch and socket) and then disconnect all the connectors that bind it to the motherboard.
In a normal modern PC we should first disconnect the main socket, the larger one, which requires you to press a lever in the center and then pull hard to pull it out, without jerking, however, otherwise the motherboard can be damaged.
Then disconnect the disc holders, the CD reader, the connector near the CPU and the one on the video card.
once all the cables are curled and disconnected, the old power supply can be pulled out.
A PC power supply consists not only of the transformer and the main switch with the plug, but also of a built-in fan and a series of cables and plugs that come out.
As mentioned above, in the non-modular power supply (which is the classic one), all possibly usable cables are included, which is not said we should all use them.
Before continuing, it is worth understanding what cables and connectors we find coming out of a PC power supply to be connected :
- P1 (PC Main / ATX connector) is the main cable with the largest socket that powers the motherboard and can have 24 pins or 20 pins with a small 4-pin plug that can be added.
This connects to the socket on the motherboard which can be 20 or 24 PIN.
If the motherboard has a 20-pin socket and the power supply has a 24-pin plug, you can connect the same by leaving 4 pins on one side or you can use the ATX adapter.
- P4 (EPS connector)
This is the cable that powers the processor and must be connected on the motherboard to a socket near the CPU.
The extra 4 pins are used on motherboards that support overclocking to give more energy.
Most power supplies have two power supply cables, one 4-pin and one 8-pin, so you can choose the right one.
If there is only the 8 Pin cable and on the motherboard the plug has 4, you can still connect leaving 4 pins out.
- PCI-E connector (6 pin or 6 + 2 pin)
The motherboard can provide a maximum of 75 W through the PCI-E interface slot.
This connector connects directly to the graphics card in the PC.
The more expensive graphics cards require the PCI-E 6 + 2 pin connector
- Molex (4-pin peripheral connector)
Molex connectors have been around for a long time, they are plastic ones with 4 holes and two cables inside each of them, one red and one yellow.
In the past these cables were used to connect hard drives and CD-ROM drives, but today they are no longer used (even if the power supplies include them anyway).
As they have been replaced by SATA cables, MoleX to Sata adapters will be included.
The Mini Molex, if present, is that of the floppy disk.
- SATA connector
The flat-shaped SATA connector is the one that is connected to the CD Rom and hard disk.
A power supply should have 4 or more SATA ports, to support multiple hard drives.
Thanks to their L-shape, the SATA power connector can only be connected the right way.
Once you have identified the various cables and the sockets on the motherboard, you just have to place the new power supply in its housing, screw it and make the connections in the right way (as the various connectors are made, you can't go wrong and attach one in place of another).
The important thing is never to force too much, use delicacy, do not tug and check the right lines.
If you are using a non-modular power supply, it is important to set aside unused cables in order to hide them, collect them and also bend them using cable ties.
In the end, close everything and turn on the PC again, which should start without problems.
READ ALSO: Guides to change RAM, power supply and PC hard disk
Switching power supplies is also a way to save energy consumed by a desktop PC, because newer PSU units are optimized to consume less energy.
For example, I have had the same PC for almost 10 years, but recently I added RAM, an SSD unit, a dedicated video card and a fan, greatly modifying the initial configuration (from which in practice only the motherboard and CPU are left) .
As a result of these changes, every time I turned on the computer I had to wait a time varying from 10 seconds to 10 minutes before the screen turned on and the BIOS loaded, long before then loading Windows.
The reason for this switch-on delay could be in the damaged motherboard, in one of the RAM memory cards, or in the power supply (500 W) that does not make it.
I then opened the case of my desktop PC and detached the extra fan and, alternatively, the two older banks of RAM noting that one of the two was damaged.
Replaced the damaged RAM, I noticed that the PC started up fast only if I unplugged the fan and I understood therefore that, at 90%, the problem was in the power supply.
Replacing the PC power supply, however, may seem something very complicated if you look at how many cables and connectors it is connected to, but there is no need to be afraid, because it is all a job to unplug and reattach them, without the possibility of make a mistake.
READ ALSO: What symptoms if the PC power supply has failed or is about to break "> buy a power supply with adequate power for the PC, it is really worth going to Amazon because the prices are very good.
Among the different PSU models on sale, the most balanced in terms of price and performance is that of Corsair, available with various power classes, for ATX houses (the large case).
In my case, since I have three discs and a level video card, I chose the 650W one.
In a normal PC, the 550 W one (which is the best-selling one) may also suffice, while if you want a very quiet one to power an economic PC you can choose the 350 W one.
Keep in mind that the Corsair that I also bought is a non-modular power supply, that is, with all the fixed cables attached.
This type of power supply is fine if you have an ATX-type thick case with space inside.
If you are using a small case, Micro ATX or Mini ATX, a modular power supply is convenient, which allows you to eliminate cables that are not used.
The modular power supply therefore allows to occupy less space inside the PC, to leave more air passage and decrease the accumulation of dust.
To change the power supply, therefore, you must first unscrew the screws outside the case in the rear (in practice around the space where there is a switch and socket) and then disconnect all the connectors that bind it to the motherboard.
In a normal modern PC we should first disconnect the main socket, the larger one, which requires you to press a lever in the center and then pull hard to pull it out, without jerking, however, otherwise the motherboard can be damaged.
Then disconnect the disc holders, the CD reader, the connector near the CPU and the one on the video card.
once all the cables are curled and disconnected, the old power supply can be pulled out.
A PC power supply consists not only of the transformer and the main switch with the plug, but also of a built-in fan and a series of cables and plugs that come out.
As mentioned above, in the non-modular power supply (which is the classic one), all possibly usable cables are included, which is not said we should all use them.
Before continuing, it is worth understanding what cables and connectors we find coming out of a PC power supply to be connected :
- P1 (PC Main / ATX connector) is the main cable with the largest socket that powers the motherboard and can have 24 pins or 20 pins with a small 4-pin plug that can be added.
This connects to the socket on the motherboard which can be 20 or 24 PIN.
If the motherboard has a 20-pin socket and the power supply has a 24-pin plug, you can connect the same by leaving 4 pins on one side or you can use the ATX adapter.
- P4 (EPS connector)
This is the cable that powers the processor and must be connected on the motherboard to a socket near the CPU.
The extra 4 pins are used on motherboards that support overclocking to give more energy.
Most power supplies have two power supply cables, one 4-pin and one 8-pin, so you can choose the right one.
If there is only the 8 Pin cable and on the motherboard the plug has 4, you can still connect leaving 4 pins out.
- PCI-E connector (6 pin or 6 + 2 pin)
The motherboard can provide a maximum of 75 W through the PCI-E interface slot.
This connector connects directly to the graphics card in the PC.
The more expensive graphics cards require the PCI-E 6 + 2 pin connector
- Molex (4-pin peripheral connector)
Molex connectors have been around for a long time, they are plastic ones with 4 holes and two cables inside each of them, one red and one yellow.
In the past these cables were used to connect hard drives and CD-ROM drives, but today they are no longer used (even if the power supplies include them anyway).
As they have been replaced by SATA cables, MoleX to Sata adapters will be included.
The Mini Molex, if present, is that of the floppy disk.
- SATA connector
The flat-shaped SATA connector is the one that is connected to the CD Rom and hard disk.
A power supply should have 4 or more SATA ports, to support multiple hard drives.
Thanks to their L-shape, the SATA power connector can only be connected the right way.
Once you have identified the various cables and the sockets on the motherboard, you just have to place the new power supply in its housing, screw it and make the connections in the right way (as the various connectors are made, you can't go wrong and attach one in place of another).
The important thing is never to force too much, use delicacy, do not tug and check the right lines.
If you are using a non-modular power supply, it is important to set aside unused cables in order to hide them, collect them and also bend them using cable ties.
In the end, close everything and turn on the PC again, which should start without problems.
READ ALSO: Guides to change RAM, power supply and PC hard disk
