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Question

20 pin power supply 24 pin mother board

by m111183 / May 29, 2013 3:58 PM PDT

I have a 24 pin motherboard and the pc would shut off after 30 mins with the original 300 watt power supply. I went to put a 20 pin power supply in place that was 250 watts and it powered up but nothing shows on the monitor except the screen lights up black. It also would not power off so I had to shut off the surge protector. I went to put the original 300 watt psu in and it still does the same thing. Could I have shorted something out or do I just need a new power supply?

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All Answers

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Answer
Did you test both supplies?
by R. Proffitt Forum moderator / May 30, 2013 12:28 AM PDT

You'll need a Volt Meter and research "power supply green wire test" to see if the power supplies are coming up.

There are too many reasons for this to fail. For example you may need some other ATX12V power lead that is common but you omitted so much detail that all I can do is note these items.
Bob

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Answer
Check the specs
by Willy / May 30, 2013 1:05 AM PDT

What did you expect to happen. Your PC needs a 24-pin PSU not a 20-pin one. While some 24 leads are 20+4 pin setups that can separate and used on 20-pin connections. The extra 4-pins are video related to provide assured power to at the time more demanding video needs. This has be supplanted by yet more power leads as in separate wire harness but added leads. In your case get another similar 300W or better PSU new or tested good and then install in your PC. While the "green wire" is a good test to assure the PSU will turn-ON it really doesn't do the other half of having all the power present under a true load. On top of all that, you could it all for granted and just installed a 20-pin in place of a 24-pin connection. Did you review the PSU specs at all, to least get a feel of what's what? Now, there's a chance when you install a new PSU it may go down if anything is wonky from the mtrbd..

tada -----Willy Happy

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reply
by m111183 / May 31, 2013 8:00 AM PDT
In reply to: Check the specs

Well the local tech support told me you could connect a 20 pin psu to a 24 pin as well as the reviews i looked up before doing so. So I went back and attempted to hook the 20 pin psu back to its pc and now it doesn't work so I'm thinking maybe the motherboard is shorting out the psu's.

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Or this needs the other 4 pin ATX12V connection.
by R. Proffitt Forum moderator / May 31, 2013 8:09 AM PDT
In reply to: reply

Can you update your post with make and model numbers of everything?

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make and model
by m111183 / May 31, 2013 8:42 AM PDT

ok the 24 pin is in a gateway gt5692 (phenom x3 64 bit) and the 20 pin was in a dell dimension 2400 (p4 32 bit)

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Then stop
by Willy / June 1, 2013 3:39 AM PDT
In reply to: reply

If your conclusion is that the mtrbd. is now breaking your other PSU, then stop. You're not going to go far if you keep this up. If the mtrbd. has gone south then that suggests some "electrical problem" has arose. It took out the PSU and possibility the mtrbd. as well, thus creating two problems. In such cases using known good parts from a test setup, breakdown the PC to its basics. Provided you want to do that, otherwise, get another used/new PC or order parts to DIY yet another PC. You decide...

tada -----Willy Happy

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Answer
Link about this model.
by R. Proffitt Forum moderator / June 1, 2013 1:34 AM PDT
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Answer
This board uses the usual CR2032 battery too.
by R. Proffitt Forum moderator / June 1, 2013 3:23 AM PDT

I see a CLEAR CMOS Jumper too. Check to see it's in its place and measure the CMOS battery. It must be over 3 Volts or some boards won't power up.

Again, name calling is not allowed here and your discussion may be cleaned up by a passing moderator.
Bob

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