Are BTX PSU's different?

[TheGreatSatan]

I have a PSU case with a BTX motherboard. I figured all would be the same and I could just use an ATX PSU, but they're not working. I tried two different PSU's with the same result. I've tried different Processors too, but no change. Should I use a BTX PSU instead? Is the pin layout different?

[slaveofconvention]

This is all based on research, not personal experience or knowledge so it's only as reliable as it's source at http://pinouts.ru/pin_Power.shtml

The only 2 differences I can see are pins 16 and 20

On an ATX PSU 16 is the green signal cable for turning the PSU on and off - 20 is white and provides -5v on older PSUs but is no longer needed in modern PCs - in BTX, 20 is not connected at all.

The power one is a little more complicated and I'm not 100% certain I understand it myself but I'll have a go.

To turn on a PC using ATX hardware, pin 16 is shorted to any ground (green to any black) by the momentary push to make power button.
For BTX it says
Active low. TTL compatible (0.1-0.8V low; 2.0 high?). When low - DC outputs are enabled. When high - power supply should not deliver DC current.

My take on that is that it requires a constant 2v to keep the PC turned off (which is just weird) and when the voltage drops to between 0.1 and 0.8v it turns the PC on. I would think that's basically a reversal of the ATX switch - normally on instead of normally off, so the BTX power button would be a "push-to-break" but if you're using a BTX case, surely it'd have the right power button IF that was the case....

Having said all that, googling around and I keep finding thing saying there is no difference at all - other than the 8 pin auxiliary 12v power connector but that's starting to appear on newer ATX boards too.

So in summary, after typing all this while googling it, I'm not sure which really isn't going to be of any help whatsoever. Sorry.

[Kayin]

My understanding is that it's still ATX compliant, but I'd have to have a PSU in front of me to know.

[FuzzyPlushroom]

Having had one friend with an ATX PSU in his BTX Gateway, I see no reason why it shouldn't work.

[nevermind1534]

Yes, they take ATX PSUs. AFAIK, there was no BTX PSU released.

[x88x]

It should work just fine; considering you've tried multiple CPUs, I wonder if the MBB or RAM might be bad? IIRC, there is no electrical difference between ATX and BTX, it was just Intel shuffling stuff around on the board to try and get better cooling.

[FuzzyPlushroom]

Intel shuffling stuff around on the board to try and get better cooling.

...and, by an odd and most unusual coincidence, making the BTX standard harder to use with the Athlon 64 that was, at the time, making the Pentium 4 look like a dog's breakfast.

Didn't stop 'em, though - my friend with the random PSU in his BTX chassis has an X2 4800+. Too bad his Gateway's such a steaming pile otherwise.

[TheGreatSatan]

I actually reallly like the case, but this is getting to be way too expensive just to get the stupid thing working

[TheGreatSatan]

It's got to be. I tried a totally different BTX motherboard with the exact same effect.

[TheGreatSatan]

I'm thinking more of this. Newegg has 11 PSU's are specifically ATX/BTX compatible (http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010090058+1131313788&QksAutoSuggestion=&ShowDeactivatedMark=False&Configurator=&Subcategory=58&description=&Ntk=&CFG=&SpeTabStoreType=&srchInDesc=). Not all of their PSU's are BTX compatible

[TheGreatSatan]

Well, there must be a difference. I ordered this (http://www.newegg.com/Product/Product.aspx?Item=N82E16817116008&cm_re=psu_btx-_-17-116-008-_-Product); I plugged it all in and it runs perfect.

[nevermind1534]

Type ATX / BTX

Looks like the PSU just says it works with ATX or BTX motherboards. That would tell me that there's no difference.

At least you got it working.

[TheGreatSatan]

Edit: Double post

[nevermind1534]

Was that an accidental double post or a reply to mine? I was quoting the specs for the PSU that said ATX/BTX, which would mean that it works with either one, making them the same.

[FuzzyPlushroom]

I'm thinking more of this. Newegg has 11 PSU's are specifically ATX/BTX compatible (http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010090058+1131313788&QksAutoSuggestion=&ShowDeactivatedMark=False&Configurator=&Subcategory=58&description=&Ntk=&CFG=&SpeTabStoreType=&srchInDesc=). Not all of their PSU's are BTX compatible

Hmm. All of those seem to have higher-than-average +5VSB (5v standby) rails - got a regular ATX PSU with a standby rail rated at 2a or higher that you can try out with that board? I can't imagine why, but that might be it; 2a was on the high side of average last I knew.

Anyway, they're wire-compatible, so it'd have to be something silly like that, or else you didn't try enough PSUs on your BTX 'board.