VERY odd PSU thing?

[SilentDeath]

I just noticed tonight, putting my pc back together, that IF the 5vSB wire from the ATX connector is too near the case (the purple one), then the psu will switch itself on and off VERY quickly, which isnt good!

Took me ages to figure out what it was, and when I relised it was teh ATX connector, I immediatly assumed the PS_ON wire (green) was the problem, but no it was the purple. Now I have some idea, but Im lost as to what actually is casuing it. The outer sheeth is not damaged, but if the wire gets within 3 or 4 mm of the case i get this prob.

[turkster]

Well i can hardly see how the 5vsb lead can ever be 3-4mm away from the PSU seeing as it is coming from it in the first place .
I presume you mean that a section of the wire causes the PSU to turn off if it gets too close. I should imagine that it is something shorting out in the atx bundle. Maybe when you move the purple wire it shorts with another in the bundle of wires? I cant see how the actual proximity to the PSU would have any effect unless there was a spark?

The of wires that come out of the PSU and go to the ATX are very tightly bundled and if you moved them around a lot i was they possibly could fatigue just where they go into the PSU.

[Lexeus]

I beleive he is saying it happens when it gets close to his pc case ? Or maybe not, Silent ?

[Steve]

Well purple is your standby voltage.

Now, are you sure it's to do with proximity to the case, or just movement of the wire? It may be significant that it's near the case, as the case is a grounded source. However, the 5V-SB wire goes into the PSU, straight past the PSU casing, also grounded.

Got any neons in there that could be causing magnetic interference down the ground?

[SilentDeath]

Im using a CWT ADP 550w psu. The ATX connector is acctually BTX, so Im using the bundled BTX->ATX converter that came with it. The extra long cables + converter resulted in the 5vSB wire touching the case (insulated though!).

Yesterday before I had this prob i done a few things - took the psu cover off (which was difficult, theres not much space in there!). I also put the extra 4 pin 12v connector through the ATX connectors braiding, as they plug in so close together.

There is a grommet thingy where they enter the psu, So the wire did not get damaged like that. Its also in the middlee of the bundle of wires, so movement shouldnt have affected it.

Also Im lost as to HOW exactly the 5vSB wire could even have this affect.

If I hold ALL the wires compleatly still but then move the 5vsb cable to touch the case it still happens, so its not related to another cable, I dont think. I cant see anywhere where it can short.

This happened for the first time yesterday.

Neons? nope. Have a CCFL but not plugged in and hasnt been for about a week - how would a neon affect it though?

[Steve]

Well that's curious. I was just thinking the neon/ccfl's ac current might have caused some sort of interference.

[turkster]

Very strange.
It must have been quiet hard to get the 4 pin 12v through the atx braid. You must have bent it round alot. I'm still thinking that it must be something shorting or breaking contact in the wire bundle. Did you try the 5vSB with a multimeter while putting it close to the case?
By the way why do you need the 4 pin 12v connector on an AMD system I thought they didnt need the extra connector?

[Steve]

Turkster: They call it a P4 connector but it's really just extra 12V connections for more power - and AMD mobo's that draw a lot of juice are going to need them, it's just Pentium boards "got there first."

Anyway, the problem could me metal fatigue from all this bending that's been going on - there might not be any external evidence, it may be internal to the cable.

[SilentDeath]

yea.. my psu also has a 6 pin 12v cable, the old AT style AUX cable and about 10 too many molex connectors - Ive decided I want to reqire my psu with only what i need. the first task is to get the right wire.
At a guess the normal psu wires are rated between 4A and 10A.
Id also like to use single core wire, the only ones I can find though are either 1/0.6 or as used in mains wiring, twin and earth would be almost perfect (the two ground wires can be shared by one) but I cant find anywhere online to buy it in small quanitiy (less than 100 meters), but thats with crappy white-impossible-to-cut sheeth
Also Id need some realy thick single core wire, as Im only going to have one wire for each rail from the psu, this will go into a small box where it spilts into all the other connectors, the idea is to make it modular, so I can unplug the connectors I wont need.

Any ideas?

Also anyone know where ATX and BTX connectors can be bought new?

Lastly where the wires conenct to pcb in my psu they are all sorta crimped and im unsure how to remove them without having to resort to mass-soldering.