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