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Need info:8-pin power supply

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Hi all.

Will appreciate assistance from members of the forum.

I have a 9-channel DVR by AVtech. Recently its power supply failed to function. I searched around for a replacement unit but ....

So I decided to custom make a power supply for the DVR.

The power supply I am making consist of 2 separate units, one supplying 12v and the other 5v.

Sounded simple, eh? But the output plug is a 8-pin plug and I need to figure out which pins are 12v and which are 5v.

Fortunately, the output supply comes with a diagram of the pins' output, showing the +12v and +5v pins. However, the -12v and -5v pins are indicated as GND only.

I need to know which of the GND pins are the -12v and which are -5v as the GND is not the common GND of a single supply. The pins concerned are pins 1, 2, 3 and 5 from the attached photo.

Will it make any difference if the -12v and the -5v are swapped?

A photo of the old power supply is attached.

 

The DVR is a 9-channel (JPEG format) non-network unit from AVtech.

 

Thanks for the assistance.

PwrSupply.3.JPG.ce2a00769d190aa87806a2f9aafa4b1f.JPG

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I need to know which of the GND pins are the -12v and which are -5v as the GND is not the common GND of a single supply.

 

Why not?

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I googled KY-05072 and found one for sale for $29.95. Unless you are looking for a project, it might be better just to buy the proper replacement supply.

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When a Power Supply is generating both 12vdc +, 12vdc - , 5vdc +, 5 vdc -, it is usually for powering a hard drive, as well as the Motherboard. You need to do a little searching for your particular PS. You might try to take a look at both Newegg and Tigerdirect, under Power Supplies for PC's. Both of these websites ( and many others I am sure), show the pin voltages of different Power Supply connectors to Motherboards. Yours might look like one of them. That would give you a starting point. Insure Polarity with your voltmeter. I have built CCTV power supplies ( 12 VDC) from PC power supplies, as they are UL Listed. Just add fuses (DIN mount), wiring, DIN rail, Nema enclosure. Don't confuse "ground" with "negative voltage" or "neutral". Good luck

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Most power supplies of that type have common grounds, even if they have multiple ground pins. You can confirm that by doing a continuity test between the ground pins with a VOM or continuity tester.

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