PSU Recommendation please..

[DaveB]

Hello Mate

Tks for the pointer

I really do find it hard to believe that the mobo has suddenly died. I know mobo's die.. even Gigabyte boards but I've never had one let go like this. Looking inside the case, you can tell exactly how much use the system has had. There is absolutely NO dust anywhere. The CPU fan is pristine and these always attract dust and rubbish. If I can get it to go as far as a POST.. I'll be happy but it's not getting close as it stands. The case fans wind up then cut. The CPU fan turns a few times then stops as does the graphics card fan. It tries again (without any intervention) then stops.. then tries again. Most bloody frustrating For sure, whatever isn't happening now is the same as what wasn't happening prior to the PSU change. I don't have much connected to the mobo so I'll work through what I DO have as suggested. The current list is as follows..

ATI HD2900XT 512mb
2 x Crucial Ballistix 1gb dimms
2 x SATA2 WD 500gb drives
1 x Liteon SATA DVDR
3 x case fans
Oh.. and 1 x E6600 intel CPU with original (new) CPU cooler/fan

Not enough there to pull the skin off a rice pud is there

ATB

DaveB

[tonymadge]

Dave, sometimes when a PSU fails it can take other bits with it, ie motherboard ram CPU etc, not good news I know.... The only way of checking is to put a known good one into the PC if it fires up then the Corsair is a dud, if it dont then your stuffed. Best way is to do as previously suggested and conect up bit at a time.
Switch Mode Power supplies will have over volts and current protection, should one fail then the PSU will go into a cycle of putting out power and then shutting down, this does two things if you have a component that has gone duff on you, ie a short circuit the over current protection will cut in to stop the PSU, likewise an open circuit component can cause a similar reaction, the voltage rails are checked for output and current. If the PSU fails and tries to put out too much power the same can happen, however the protection circuits should stop any component getting damaged on the PC, in theory... Sadly in practice it does not always do this. I recall in my TV repair days that sometimes a failed power supply will damage other stuff, not often but can happen...
The reason your present symptoms are different from origianl ones could point to the new PSU working but the fault lies elsewhere...this also points to the old PSU taking something else with it to its grave

I cant think of any good news ..I hope I am wrong as it will be an expensive repair job...

[tonymadge]

As an after thought this is the identical set up to mine and it eats FS!! I know more expense but trust me with this you can normally unlock the other two cores so have a 4 core CPU running at 3.6Ghz!! Even on two cores (which I have mine back to now) it is very very fast with 6mb of level 3 cache.
Just in case its not repairable....

http://www.overclockers.co.uk/showprodu ... ubcat=1334

[emfrat]

DaveB -
Two experiences of mine that may have some relevance:
I replaced a working PSU with a more powerful one which was known to be good. (it came out of a machine which was working fine). When I switched on again, my machine did not want to play at all. Then I noticed there were two possible sockets (side by side on the Mobo) for a 4-pin connector with black/yellow cabling. I assumed the obvious, swapped sockets and it has been working ever since.

The other involved replacing a CPU fan. It was only when the new one arrived that I noticed it had one wire less than the old one. I installed it anyway, and when I tried to start I got this 'begin starting - shut down' routine like you describe. After a bit of a search around the net, it appeared that the new PSU was interrogating the CPU fan to see if it was running; the new fan was lacking the wire to receive or respond to the question, so the PSU was shuttting down to avoid damage.

As I recall (and I do not recommend this 'fix' to anyone - it is your own risk entirely) I waited for the coolest hour of the night, set up a big pedestal fan to blow into the open box, disconnected the lead from the CPU fan, and started up with no fan at all, just long enough to get into the BIOS and tell it not to check for fans. I took that very dodgy step after establishing that if I disconnected the new, and reconnected the old 3-wire one which I held in my hand, it started up OK.

In my experience, computers either fail in the first few days or run for ages. I hope you are seeing some weird side-effect rather than a mobo disaster. Either seems possible, but I feel the latter is less likely.

ATB
MikeW

[tonymadge]

Good point Mike, the plug may be the answer to Dave's problems

[DaveB]

Hi Guy's,

TksVM for the input. I wish I could guarantee the old PSU was either working or otherwise. All I know for a fact is that I'd noticed the pc had switched itself off earlier in the week and a push on the ON button fired it up again. I wasn't there to witness the shutdown.. simply that I came back to it and it was turned off (the monitor lamp was flashing). The day before it failed, it seemed reluctant to start.. 2 or 3 presses on the ON button but on it came and all worked fine. The next morning.. mucho presses and nada. Immediate assumption was the PSU had failed hence getting a new one. The Corsair has zillions of leads and I can see (now) why the extra few quid on a modular version would have been a good idea.
The mobo is a Gigabyte GA-P35-DS3L rev2. The ATX socket is full length (24pin) and there is a 4-pin ATX 12v socket directly above the CPU. The Corsair comes with 2x4+2 12v cables.. not sure what the additional 2 are for but I gather some mobo's have an 8-pin ATX hence the provision of 2 from the PSU. I've tried both already.

As for the CPU fan.. I'm not sure what to think. It's a bog standard Intel unit which plugs into the mobo. As previously mentioned.. the inside of the case is spotless. One thing I note was that the old PSU had a fan cable (3hole..2wire black/yellow) coming from it which I believe I'd plugged into something but can't remember what. The new PSU doesn't have this. I can't be sure but I THINK I plugged it into pwr_fan which now sits unused. CPU fan wasn't touched.. SYS_FAN1 was powered off an old style IDE 4pin via adaptors and was reconnected in the same fashion.

There may be a simple, though to my mind illogical, answer to the problem and I'll try and work up the enthusiasm to attempt all of the above

ATB

DaveB

[TSR2]

Really stupid suggestion... but try disconnecting the power and reset button and then quicly shorting the power pins on the power connection to get it to come on.... long shot.

[DaveB]

...quicly shorting the power pins on the power connection to get it to come on.... long shot.

Err.. I don't do shorting things out mate.. as a rule

ATB

DaveB

[DaveB]

Hi Guy's..

Now.. I'm worried. I've disconnected the 4-pin ATX pwr lead and the fans wound up.. no recycle

EDIT..
OK.. this is where I begin to fear the worst. The 4-Pin ATX plug (as I understand it) feeds the cpu (this may be 8pin on some systems). The 8-pin split plug that comes with the Corsair cannot be fitted incorrectly.. that is, the wrong side of the 4 will not fit as the plugs are all square and the holes in my 4-pin socket are a mixture. Thank goodness they made it fool proof Same scenario.. do not connect the 4-pin and the fans wind up and there's pwr to the mobo. Add the 4-pin and the system goes into cycle mode. I've stuck a test meter on the output from the Corsair and it is giving the correct voltage.. that is, 12v. Am I to assume then that either the 12v feed from the mobo to the cpu is effed or alternatively.. the CPU itself?? I fear a rock and a hard place is where I'm at now. I don't have a spare 775 chip to throw onto the mobo as a test nor do I have a spare 775 system to throw the E6600 onto. With power going to the mobo and 12v coming from the ATX 12v plug.. I think the term I'm thinking of ends in CKED

Does this seem like a logical prognosis

ATB

DaveB

ATB

DaveB

[TSR2]

Have you tried taking the memory dims out one at a time Dave?