Can I replace my old 200W PSU without damaging my mobo/new PSU

[CrossBird]

I have pre-built system that I suspect has lost it's PSU. For the last few weeks (actually over a month) I have needed to press down the power button for nearly 10 minutes before it lumbered on. Now, even that does not work.

System config in brief:
Mobo - G41 DDR3 L775 mATX
CPU - PDC E5500 2.8Ghz
PSU - TFX 200W 24-Pin (Delta) - I think it's this one
RAM - 2 GB DDR3
OS - Windows 10 (originally Win 7, upgraded to Win 8, upgraded to Win 10)

Will I be able to replace the above PSU with a Seasonic S12II-520? I don't want to fry my existing mobo, but more importantly, I don't want the new PSU to be damaged due to incompatibility.
If the new PSU doesn't get things going, I plan to build a new system with it. So, more than the mobo, I am concerned about not damaging my PSU in some way.

 

[Paperdoc]

Before replacing the PSU, check for this other possible cause of your trouble. What you describe MIGHT be just a bad Power pushbutton switch in your front panel. There are a couple of way you can test.

1. Open your case and find the Front Panel header, usually near the bottom right (front) of the mobo. It will have several wires coming to it from the front panel, and labels on its pins. Find the two wires (usually in one connector) for Power Switch. Disconnect that. Now, find a similar pair of wires for Reset Switch. Disconnect those Reset wires and plug them into the pins for Power Switch. The two switches are the same type, so this action converts your front panel Reset pushbutton into a replacement Power button. Now, use that Reset button to turn on your machine. If it works, shut down and try again. If it keeps on working, you have a temporary solution already. You have a Power Switch on the front, but it has a Reset label on it. And you don't have a Reset button. But your machine is working again.

2. If that does not work, MAYBE the Reset pushbutton also is in poor condition, and you can try one more test, the "Screwdriver Test". Disconnect the Power Switch connector as above and leave its two pins bare. Now, take a narrow metal tool like a screwdriver blade and use that to short together those two header pins for just a second or so, then remove the screwdriver. That will mimic the action of the normal Power switch (just a momentary connection while pushed). If that action starts the machine right away, and if you can do this reliably many times, then the system is all OK. Just the front Power pushbutton is faulty.

Let us know what happens.

 

[ko888]

You cant replace a TFX form factor PSU with an ATX form factor PSU because the sizes are completely different unless you're moving the motherboard to a new ATX/mATX computer case.

 

[CrossBird]

Before replacing the PSU, check for this other possible cause of your trouble. What you describe MIGHT be just a bad Power pushbutton switch in your front panel. There are a couple of way you can test.

1. Open your case and find the Front Panel header, usually near the bottom right (front) of the mobo. It will have several wires coming to it from the front panel, and labels on its pins. Find the two wires (usually in one connector) for Power Switch. Disconnect that. Now, find a similar pair of wires for Reset Switch. Disconnect those Reset wires and plug them into the pins for Power Switch. The two switches are the same type, so this action converts your front panel Reset pushbutton into a replacement Power button. Now, use that Reset button to turn on your machine. If it works, shut down and try again. If it keeps on working, you have a temporary solution already. You have a Power Switch on the front, but it has a Reset label on it. And you don't have a Reset button. But your machine is working again.

2. If that does not work, MAYBE the Reset pushbutton also is in poor condition, and you can try one more test, the "Screwdriver Test". Disconnect the Power Switch connector as above and leave its two pins bare. Now, take a narrow metal tool like a screwdriver blade and use that to short together those two header pins for just a second or so, then remove the screwdriver. That will mimic the action of the normal Power switch (just a momentary connection while pushed). If that action starts the machine right away, and if you can do this reliably many times, then the system is all OK. Just the front Power pushbutton is faulty.

Let us know what happens.

Paperdoc, thanks for your views and solutions.
I suspected the s/w too, initially. So I opened up the case and in trying to find out where the cables led amidst the tangle of wires, managed to removed all three (powed LED, HDD LED, Power s/w - no reset s/w) out of their sockets. Now I'm having a difficult time figuring out which goes where, though I've looked up a few tutorials and I think I know. Since the system was pre-built, it doesn't have a mobo manual. There are some microscopic markings, and that plus the tutorials should help me place them correctly.

With no reset s/w (button) I don't know how I can try number 1 (perhaps put the power s/w connector in the reset header pins?), but I honestly don't know if I dare try number 2.

Why I think the 200W PSU might be dead, is that it was meant for a fairly stable Win 7 OS with no system upgrades. There were no system upgrades, but the OS went from Win 7 to 8 to 10. What's more, Win 10 was a pain last few times I used it on that PC, coz there was more update time than actual productivity time! In addition to the frequent updates and the system doing overtime, supporting Win 10 itself might have sucked the life out of that PSU. Could be wrong, but a 200W PSU to support a modern OS with all it's (frequent) updates I feel may have been too much to handle.
I will nevertheless use your suggestions and see if it works. Thanks again, and any more insights are welcome.

 

[CrossBird]

You cant replace a TFX form factor PSU with an ATX form factor PSU because the sizes are completely different unless you're moving the motherboard to a new ATX/mATX computer case.

ko888, thanks for the heads up. If the TFX PSU is truly dead, I plan to move the mobo out to a new mid tower case.

If it doesn't work even with the new Seasonic PSU, then I'll opt for a full system upgrade, in which case I want to be able to reuse the new PSU. And that's why I am more worried I don't break the new PSU in trying to spice up an old hag motherboard.

 

[CrossBird]

So, doing a bit of research led me to this, the paper-clip test for the PSU. It failed - both while installed in the cabinet (connected to CPU, hard disk and DVD writer) and outside (disconnected). I tried pairing the green wire with different ground (black wire) connections, but it won't budge. So I guess the PSU is indeed dead.

Before I get a new Seasonic 520W, thought I'd mention that I have a 4-pin CPU power receptacle on my mobo. Will this be a problem when using a PSU with a 8-pin connector?

Again, any ideas if it's okay to pair a 520W PSU with a mobo that was initially paired with a 200W PSU? I will be prepared for the darn thing to blow up, but I'd hate to see my new PSU beyond use thereafter.

On a side note, I still haven't tried the "Screwdriver Test" mentioned by Paperdoc. Will it be worth trying after the paper-clip test failed?

 

[ko888]

The Seasonic S12II-520 uses a (4+4)-pin CPU power connector that splits into two 4-pin CPU power connectors.

The system will only draw as much power from the power supply unit as it needs. If the system only needs 150 watts DC then that is all it will draw from the power supply unit. If you connect the PSU's AC power cord to a power meter you would most likely measure an AC power draw of around 183 Watts since AC-to-DC power conversion is not 100% efficient. Don't be under the mistaken assumption that the PSU is always putting out 520 Watts.

 

[Paperdoc]

The "paper clip" test and the "screwdriver" test are the same thing electrically. In each case one creates a brief short from a particular signal pin to Ground, and this is what causes the mobo to turn on IF the PSU is working. The difference between them is just access to the two circuit points. In the "paper clip" test you use a wire to connect two particular color-coded wires at the PSU output connector. In the "screwdriver" test you do the same thing, but the contacts are two adjacent pins on the mobo's Front Panel header.

 

[ko888]

The paperclip test only tests whether or not the PSU is still functioning. If the PSU doesn't function with this test then replace the PSU.

The screwdriver test may fail to turn on a perfectly functioning PSU if there is a defect in a component on the motherboard or the motherboard detects what it thinks is out of spec voltages from the PSU.

 

[CrossBird]

The Seasonic S12II-520 uses a (4+4)-pin CPU power connector that splits into two 4-pin CPU power connectors.

The system will only draw as much power from the power supply unit as it needs. If the system only needs 150 watts DC then that is all it will draw from the power supply unit. If you connect the PSU's AC power cord to a power meter you would most likely measure an AC power draw of around 183 Watts since AC-to-DC power conversion is not 100% efficient. Don't be under the mistaken assumption that the PSU is always putting out 520 Watts.

Thanks, ko888.
I think I'd be fine with that 4-pin after all. I guess I only need to plug in one of the (split) 4-pin for the CPU.

I understand that only the required amount of power will be drawn. My concern stems from what a computer repair guy told me (something I should have perhaps mentioned earlier?). He said that because this is a pre-built system, it may not accept any odd PSU. He didn't mention whether it was on account of amperage or some such. All he said was that I'd need a replacement PSU of the same type, and since the company (that pre-built the system) no longer supports it, I will have to junk it/upgrade it.

Problem is, my Win 10 is attached to the mobo of the darn thing. Besides, if the mobo is still good, no reason why I shouldn't use it - for basic stuff, no gaming. So, just wondering if all pre-built systems come locked (in a way) to their PSUs? Are they configured in some way to only work with A particular PSU type and none other?

 

[CrossBird]

The "paper clip" test and the "screwdriver" test are the same thing electrically. In each case one creates a brief short from a particular signal pin to Ground, and this is what causes the mobo to turn on IF the PSU is working. The difference between them is just access to the two circuit points. In the "paper clip" test you use a wire to connect two particular color-coded wires at the PSU output connector. In the "screwdriver" test you do the same thing, but the contacts are two adjacent pins on the mobo's Front Panel header.

Paperdoc, thanks. Understood. Yes, it could be a useful little trick, but I'd hesitate to do the screwdriver test. Perhaps because I might short other pins, or because the screwdriver might touch (connect) two points on the mobo that don't like each other.
I agree though that sometimes it may come in handy.

 

[ko888]

Problem is, my Win 10 is attached to the mobo of the darn thing. Besides, if the mobo is still good, no reason why I shouldn't use it - for basic stuff, no gaming. So, just wondering if all pre-built systems come locked (in a way) to their PSUs? Are they configured in some way to only work with A particular PSU type and none other?

If you're running the Windows 10 Anniversary edition or later you can change the digital license to be linked to your Microsoft account instead of to your motherboard. It makes it easier to reactivate the operating system when you replace hardware.

Instructions here:
http://www.windowscentral.com/how-re-activate-windows-10-after-hardware-change

Some pre-built systems use a power supply that runs on 12V only (i.e. +12V, -12V and +12Vsb). The power connectors on the motherboard are not compatible with an ATX12V standard power supply that most desktop systems use.

 

[CrossBird]

If you're running the Windows 10 Anniversary edition or later you can change the digital license to be linked to your Microsoft account instead of to your motherboard. It makes it easier to reactivate the operating system when you replace hardware.

Instructions here:
http://www.windowscentral.com/how-re-activate-windows-10-after-hardware-change

Some pre-built systems use a power supply that runs on 12V only (i.e. +12V, -12V and +12Vsb). The power connectors on the motherboard are not compatible with an ATX12V standard power supply that most desktop systems use.

ko888,
My PSU sticker reads:
+5V / 13A
+3.3V / 11A
+12V / 16A
-12V / 0.3A
+5VSB / 2A
+3.3V & +5V TOTAL OUTPUT POWER CAN'T EXCEED 80W

It has a single 12V rail, and from the looks of it outputs 3.3V, 5V and 5VSB in addition to the 12V.
So, will the CPU/mobo that used this PSU work with a Seasonic S12II-520?

Thanks for the Windows 10 activation/re-activation tip. I think I did activate windows 10 on the system before the PSU died, but I'll have to check again. Need to get this system going first. Hoping a new PSU will start it up.

 

[ko888]

ko888,
My PSU sticker reads:
+5V / 13A
+3.3V / 11A
+12V / 16A
-12V / 0.3A
+5VSB / 2A
+3.3V & +5V TOTAL OUTPUT POWER CAN'T EXCEED 80W

It has a single 12V rail, and from the looks of it outputs 3.3V, 5V and 5VSB in addition to the 12V.
So, will the CPU/mobo that used this PSU work with a Seasonic S12II-520?

Thanks for the Windows 10 activation/re-activation tip. I think I did activate windows 10 on the system before the PSU died, but I'll have to check again. Need to get this system going first. Hoping a new PSU will start it up.

Your TFX PSU's electrical specifications are based on the ATX12V power supply design guide specifications. If you're moving to an ATX form factor case then you can use the Seasonic S12II-520 without any problem.

I'm assuming your motherboard is using a standard size (20+4)-pin main motherboard power connector. There are some pre-builds that use a smaller version of (20+4)-pin main motherboard power connector and would require an adapter cable. What brand and model of pre-build do you have?

 

[CrossBird]

Your TFX PSU's electrical specifications are based on the ATX12V power supply design guide specifications. If you're moving to an ATX form factor case then you can use the Seasonic S12II-520 without any problem.

I'm assuming your motherboard is using a standard size (20+4)-pin main motherboard power connector. There are some pre-builds that use a smaller version of (20+4)-pin main motherboard power connector and would require an adapter cable. What brand and model of pre-build do you have?

ko888,
It's a Dell, but I don't know the model number etc. I do remember it was purchased in a retail store in 2010. It came pre-installed with Win 7 Home Basic.
The current PSU has a 20+4 pin connector that goes into a 24-pin receptacle on the mobo. No adapters.

Also, just checked the older PSU's pins - shapes and wire colors. They appear to be standard like here. Only the 13th line appears to have a brown wire in addition to an orange one. The 20th pin is empty - no wires.
It appears to be standard.

 

[ko888]

ko888,
It's a Dell, but I don't know the model number etc. I do remember it was purchased in a retail store in 2010. It came pre-installed with Win 7 Home Basic.
The current PSU has a 20+4 pin connector that goes into a 24-pin receptacle on the mobo. No adapters.

Also, just checked the older PSU's pins - shapes and wire colors. They appear to be standard like here. Only the 13th line appears to have a brown wire in addition to an orange one. The 20th pin is empty - no wires.
It appears to be standard.

The ATX12V v2.3 and EPS12V v2.92 specs required the addition of a remote sense wire (i.e. light gauge brown jacketed wire) to be used to regulate the +3.3V rail.

 

[CrossBird]

The ATX12V v2.3 and EPS12V v2.92 specs required the addition of a remote sense wire (i.e. light gauge brown jacketed wire) to be used to regulate the +3.3V rail.

Ko888, thanks.
So the power connector seems fine and standard ATX. Just wondering if there is a certain color coding for the CPU connector pins as well. I haven't quite come across anything on that.

 

[ko888]

The ATX12V v2.3 and EPS12V v2.92 specs required the addition of a remote sense wire (i.e. light gauge brown jacketed wire) to be used to regulate the +3.3V rail.

Ko888, thanks.
So the power connector seems fine and standard ATX. Just wondering if there is a certain color coding for the CPU connector pins as well. I haven't quite come across anything on that.

From the ATX12V Power Supply Design Guide:

 

[CrossBird]

From the ATX12V Power Supply Design Guide:

Thanks a ton, ko888.
2 Blacks, 2 yellows, and pin shapes are the same. Matches exactly. I think I can go ahead and get that Seasonic now. But, I'm going to be prepared for something nasty all the same. :lol: