My wifes computer has a ECS K7SEM Socket A motherboard with a SIS 730S chipset. The power supply went bad a few weeks ago. I purchase two power supplies. Neither of them will work in her computer. I installed an old power supply that I repaired sometime ago and it works. All of the power supplies are ATX. At first I thought I'd gotten 2 bad power supplies so I purchased a Antec ATX power supply tester. Both of the new power supplies tested good. Why can't I install one of these new power supplies and have it work? There has to be a reason. I'd like to find the answer so I can change out the old PSU-I doubt if the old one will last for long. Has anybody experienced this before? Does anybody have an idea why the new power supplies will not work with this board?
Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations Mike Lewis on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
Power Supply Issue
- Thread starter jmtjet
- Start date
jmtjet,
I have to ask the obvious just to insure that it is not over looked: Som newer ATX PS have 24 pin mobo power connectors. Is this the case?
Were the 2 PS able to plug up? and then did not function?
Did the PS power up (fan & such) but did not enable the system to function.
All this is to lead to the connector. I have a stack of PS's that came with cases. Most all cases/PS have very cheap PS's and the connector is one area that is a shortcut. the pins can be just flaky. a tester would show function while it actuall does not connect reliably when plugged to the mobo.
Have a look and maybe post back with the conditions surrounding the failure.
rvnguy
"I know everything..I just can't remember it all
I have to ask the obvious just to insure that it is not over looked: Som newer ATX PS have 24 pin mobo power connectors. Is this the case?
Were the 2 PS able to plug up? and then did not function?
Did the PS power up (fan & such) but did not enable the system to function.
All this is to lead to the connector. I have a stack of PS's that came with cases. Most all cases/PS have very cheap PS's and the connector is one area that is a shortcut. the pins can be just flaky. a tester would show function while it actuall does not connect reliably when plugged to the mobo.
Have a look and maybe post back with the conditions surrounding the failure.
rvnguy
"I know everything..I just can't remember it all
- Thread starter
- #3
They both are standard 20 pin ATX connectors. One PS is a Rosewell 450 watt with dual cooling fans ver. 2.03 from Newegg. The other is a Xpower 550 watt with dual cooling fans ver. 2.03. The Rosewell is a fairly expensive PS but the Xpower is a cheaper one. Neither would work. I emailed ECS tech support with this question. The only thing they could think of was a bad ground. But if that's the case why would the one I repaired(replaced fan) work without a problem? I tested the voltage output of the new ones with an Antec ATX power supply tester and all voltages were within spec. Also, tested the 20 pin MB connector-both tested good. I'm at a loss as to why the old repaired PS will power up this computer and neither of the new ones won't. The board is about 4 years old.
THanks for your reply.
THanks for your reply.
Usually its because AMD cpu's and rails have different (higher voltage) demands from Pentium. But you seem to have this covered and you have actually tested the voltage of each rail (line)?
There is only one thing i can think of. With the power supply connected to an on\off switch and plugged into the wall, press and hold the on\off switch for a full minute without letting up at all. This will re-set the power supply and is needed to be done sometimes. I dont know why i just know it happens and the reset works.
This may or may not solve your issue but it does work.
I have a lot of experience with installing power supplies.
Good advice + great people = tek-tips
There is only one thing i can think of. With the power supply connected to an on\off switch and plugged into the wall, press and hold the on\off switch for a full minute without letting up at all. This will re-set the power supply and is needed to be done sometimes. I dont know why i just know it happens and the reset works.
This may or may not solve your issue but it does work.
I have a lot of experience with installing power supplies.
Good advice + great people = tek-tips
- Thread starter
- #5
All is normal there with the power supplies he has in so far as they should run an athlon and thats what he is running. The motherboard, ECS K7SEM. I believe i have one of them on hand. I know i have worked on a few of them over the last couple years. Its a standard 20 pin for sure, standard all the way.
With ECS motherboards you do have to re-set bios by the manual as it varies from standard variation! Check your manual and try a bios re-set, may do the job for you.
The atx version of the power supplies is very new, if not the newest at v2.03. If your other power supply that IS working is not v2.03 then that may be a possible clue as to the problem.
Good advice + great people = tek-tips
With ECS motherboards you do have to re-set bios by the manual as it varies from standard variation! Check your manual and try a bios re-set, may do the job for you.
The atx version of the power supplies is very new, if not the newest at v2.03. If your other power supply that IS working is not v2.03 then that may be a possible clue as to the problem.
Good advice + great people = tek-tips
Heres some info on power supplies:
Good advice + great people = tek-tips
Good advice + great people = tek-tips
- Status
Similar threads
- Locked
- Question