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Replacement PSU wiring compatibility

Tags:
  • Power Supplies
  • Compatibility
  • ATX
  • Components
Last response: in Components
January 25, 2009 12:42:17 PM

Hi,

I am trying to replace my Bestec-ATX-250-12Z RevC with a PCPower 470 ATX. I was assured that the new PSU was fully compatible. However, when I come to install the new PSU, the wiring on the ATX motherboard connector appears to be different. (This may be down to my lack of knowledge of course!).

The new PSU comes with a 24-pin connector, but also a 20-pin 'convertor'. All the wiring matches on each of the 20-pins, including the empty pin-18. The problem is that the old PSU has 2 additional cables:

Pin-11 additional brown wire (as well as orange)
Pin-20 additional pink wire (as well as red)

Does anyone know what's the purpose of these additional cables? Do you think I can use the new PSU without them?

Any advice gratefully received.

Thanks,
K

More about : replacement psu wiring compatibility

a c 144 ) Power supply
January 25, 2009 1:28:57 PM

Brown and pink are not "standard" colors.

The usual thing that most PSU manufacturers do to maintain backwards compatibility with the old motherboards (20 pin connector) is to make a 4 pin block of wires removeable. That removeable 4 pin (2 X 2) block has a yellow wire (12 volts), a red wire (5 volts), orange wire (3.3 volts), and a black wire (ground). Ifyour motherboard has a 20 pin main power connector, simply tie the 4 pin block back out of the way and plug the 20 pin section into the motherboard.
January 25, 2009 1:48:55 PM

Thanks for the reply jsc, but I'm afraid it doesn't answer my question.

I don't have a problem with the 24/20 pin compatibility, the new PSU wiring matches the old and you are correct that the yellow.red,orange.black wires are removed when I add the 24>20 pin convertor provided by PcPower.

The problem is that the old PSU has additional cables in Pins 11 & 20 (on the 20-pin connector). These additional cables are coloured brown (pin-13) and pink (pin-20). These are in additional to the 'standard' orange & red cables in pins 13/20 respectively.

I've no idea what these pink & brown cables are meant to be doing? and whether I can try to boot up the pc using the new PSU?

Thanks for any help,
K
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a c 144 ) Power supply
January 25, 2009 3:12:25 PM

I don't know what the pink and brown wires are doing either. I googled the Bestec PSU. I saw the no Rev, Rev C, and Rev D. One of the "no Rev" sites had colored pictures of the connectors and it did not show any pink or brown wires. My best guess is: "Don't worry about the extra wires on the old PSU."

I would tell you to plug in the new PSU and try to boot. Disclaimer: I am far, far away in Saudi Arabia, so if your PC blows up :)  , I am safe.

Seriously, except for some of the older Dells, PSU cabling is pretty standard.
January 25, 2009 4:13:36 PM

I think you should try to boot with the new PSU as this is what I would've done if I were you (I've been around computers for 10 years but there's always much to learn).

Best wishes,
youssef 2010
January 25, 2009 5:00:37 PM

Thanks for the replies guys!

I have now booted the pc using the new PSU and all appears to work ok. All components have started, fans are running (off motherbaord) rather than direct off PSU.

Still puzzled what the extra cables were supposed to be doing.

Thanks again,
K
November 29, 2011 2:18:26 PM

Hi, I know this thread is old but thought that some additional info might be useful to anyone else coming up with the same question later on. I too replaced an old PSU of the exact same make (Bestec-ATX-250-12Z) which has the same additional brown and pink wire, with a standard ATX PSU (Casecom ATX 500W.) The old Bestec had died on me after the PC had had trouble booting up for a number of months. The new PSU looked more or less identical except that the Bestec did not have an on-off switch and the screwed in area around the kettle lead input on the new PSU protruded which meant I had to remove a bit of metal from the case to fit the new one in. Anyway the PSU and processor fans came on after switching on as did the LEDs but no monitor, hard disk or CD. Tried the keyboard and 3 lights briefly flashed once. CD wouldn't eject. So I decided to do a bit of research in case the new PSU was incompatible. (A small lime green light comes on on the motherboard next to the 20 pin connector and just below the 3 largest cylindrical batteries of the motherboard. So the motherboard appeared not to be dead at least, especially since some things are receiving power. I took a good look at my old PSU and compared it to a diagram on Wikipedia and noticed the pink and brown wires in the positions that you mentioned. Otherwise the wiring looked pretty standard.)

After some more research I found some sites that say the extra wires are sensor wires that detect changes in voltage and adjust to compensate. They seem to be optional, like the white wire which my new PSU has. Given that they are optional and in the standard positions unlike some proprietary brands it suggests that it wouldn't do any harm to use a new standard PSU. Although I've got problems with some of my hardware starting it may be that some of it got damaged when the old PSU died or that the motherboard hasn't fully woken up from being unplugged for a week and plugged into the dead PSU for even longer before that. I'll post how I got on. The fact that your hardware worked when you finally decided to risk plugging it in would seem to prove that the standard ATX is OK as a replacement for the one with the pink and brown wires.

As I said the pink and brown just seem to be optional sensor wires.

Thcube said:
Hi,

I am trying to replace my Bestec-ATX-250-12Z RevC with a PCPower 470 ATX. I was assured that the new PSU was fully compatible. However, when I come to install the new PSU, the wiring on the ATX motherboard connector appears to be different. (This may be down to my lack of knowledge of course!).

The new PSU comes with a 24-pin connector, but also a 20-pin 'convertor'. All the wiring matches on each of the 20-pins, including the empty pin-18. The problem is that the old PSU has 2 additional cables:

Pin-11 additional brown wire (as well as orange)
Pin-20 additional pink wire (as well as red)

Does anyone know what's the purpose of these additional cables? Do you think I can use the new PSU without them?

Any advice gratefully received.

Thanks,
K