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Minus 5 volt missing from new PSU. Compatible? 3

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torandson

Technical User
Feb 8, 2005
239
A1
Hi all,

Recently I purchased an Antec TP II 430 W PSU only to discover that it has no minus 5 volt output. No mention of this on the box or online.

I have a DFI Lanparty UT 250Gb mobo for which the set-up guide labels the pins of the 20-pin connector, including the -5v pin. This contact is missing from the Antec connector.

Sadly, I can find almost no information on the web about this issue. Only a vague mention on an obscure site somewhere to the effect that "few systems use this voltage anymore... usually used for audio, etc. ..."

DFI does not list compatible PSUs.

Antec does not list compatible mobos.

No one bothers to mention even general information about PSU rails and voltages unless it's a selling point.


--->>> Will this PSU work with my mobo? <<<---


Why don't manufacturers explain things plainly when they make major revisions to their products?

--torandson

"I ask again for common courtesy; it seems again I ask too much." --Nuddar Dufis

 
Treeking,

Are you sure the plug is 20-pin?

Quite sure. I counted 'em. Says so in the user manual. Shows so in the diagram. Says so on the spec sheet. The 20-pin connector fits the socket; the detachable four pin section doesn't.

According to here:

That's not my mobo. Mine is a Lanparty UT nForce3 250Gb socket 754 board. 20-pin.

Yes, you linked to the right PSU.

Though I'll have to take your assurance with a grain of salt, Antec assures me that -5v is obsolete and I'm good to go.

I'm sure it must be so, but I'd feel better hearing that from someone who also knows my particular mobo, though.

--torandson
 
torandson said:
The 20-pin connector fits the socket; the detachable four pin section doesn't.

The detachable four pin connector is not used on AMD mobo's.

DFI's spec sheet at certainly looks like you'll have no issues. Have you had any?

Wishdiak
A+, Network+, Security+, MCSA: Security 2003
 
-5volt no longer required
I can vaguely remember one of our top members answering this very question some time ago The conclusion I believe was something along the lines of: it was no longer a requirement of the Intel specification??


As for quote: "The detachable four pin connector is not used on AMD mobo's"

It certainly is on most of the latest AMD boards.

Martin

We like members to GIVE and not just TAKE.
Participate and help others.
 
paparazi,
Thanks, this is the most relevant response yet, but it still doesn't quite answer my question.

The fact that -5v is no longer a part of Intel's specification strongly suggests that this PSU is probably compatable with my mobo.

(BTW everyone, I mentioned the detachable 4-pin connector simply as evidence that my mobo has a 20-pin connector. This detail is otherwise irrelevant.)

However, there is a pin socket on the 20-pin mobo that is labled "-5v" in the user set-up manual. No other information is available from DFI. (In other words, there is a trace on the mobo that is labled "-5v". So it is a reasonable question to ask if it is used for anything.)

Since I replaced the PSU in response to a system lock-up issue (possibly driver, possibly OS, possibly hardware), Wishdiak's question "Have you had any (issues)?" is "Yes, that's why I am asking." But the problem originally showed up before the PSU was replaced with the one in question, so the -5v issue simply complicates the troubleshooting process and may or may not have anything to do with the problem. As I said, the 20-pin connector is mentioned in the spec sheet. If that information were sufficient to answer the question, I would not have asked it.

The previous PSU is good. It has -5v. It is only a year old. I replaced it because I thought it might not be strong enough to handle some additional hard drives I recently installed. That modification appears to have caused the lockup of the system when a CD or DVD is inserted into the Combo optical drive. This problem is not yet resolved. Sadly, it still occurs even after removing the new hard drives from the system and disabling them in BIOS. It occurs while a voltmeter shows the +12 volt rail to be rock-steady. I haven't yet put the first PSU back in the system to see what happens in that case with the new hard drives omitted, because that's a major deal with so many connectors to fuss with.

For all these reasons it is important that I know the answer to THIS question:

Does my mobo use or require -5v in any way?

Statments with respect to a general Intel standard do not answer this question.

Antec responded that the new ATX 2.0 standard does not require the -5v and that labeling the -5v pin on the mobo diagram does not mean that the voltage is used. They say I'm okay.

But no one has yet answered my question with the particular statement of known fact that has actually been requested.

Does the DFI Lanparty UT nForce3 250Gb socket 754 mobo use or require -5v in any way?

--torandson
 
[bigsmile] So yes, it will be compatible (should have said) with that motherboard.


I will add: these V2.0XX have seperate 12volt power rails so don't just use one cable to connect the main consumers, HDD's and graphics cards, spread the load, use a seperate cable for each.

I have to say, given your diagnostics thus far, the PSU is unlikely to be the cause of the lockups (two different PSU's, same problem with or without HDD's attached)

Maybe you could post some more info, specs/software etc.

Martin



We like members to GIVE and not just TAKE.
Participate and help others.
 
paparazi,
Thanks, but I've seen that Antec page. I appreciate you taking the time to reply, though.

I'd still be happier if someone with this mobo said unequivocaly "I factually know that this mobo does not use -5v for anything at all based upon empirical evidence X."

As for the BTC DVD/CDRW Combo lock-up problem, more is available at this thread:

thread779-1183694

--torandson
 
Found this additional info:

1.2.1. Key Changes for ATX12V Version 1.3
...

-5V removal: Guidance for –5V has been removed.

This legacy voltage was in support of ISA add-in cards. ISA cards are no longer used for a majority of the industry, but custom applications my still exist, refer to Version 1.2 for –5V recommendations.

File Reference:
 
JimInKS,
Thanks, that information is much more reassuring than anything I've heard yet.

There are no ISA slots on this mobo as far as I know, and knowing that -5v guidance was removed from the version 1.3 spec and that version 2.0 dates from 2002 produces a noticable reduction in the system operator's system-stress-level meter. :)

That, ... and the fact that a new optical drive solves the system lockup problem even if it doesn't exactly explain it. (The problem optical drive works in another system, which is also happy to get the Antec 380 that was replaced by the Antec 430.)

--torandson

 
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