FAQ:  PSU FOR ECS K7S5A MOTHERBOARD (4)
Jiggs 22 Dec 2001

11.  When I turn on my system, the LED’s will come on for a second and then it totally shuts off with no indication of power.  I wait for a couple of minutes or less, push the  power “On” switch and then LED’s will come on for a second and then off again.  What is wrong?

You either have a faulty PSU or mobo or your PSU is seriously underrated.  The quick on and off of the LED’s indicates the PSU tripped off its circuit protection.  Either because the PSU has internal problems wherein the output voltage are way too high or way to low. Most PSU have over voltage protection, which is usually set at 150% of the output rails. Or it could be there is a short in the mobo or the mobo could be shorted to the case.  A short circuit of the mobo circuit to the case or internal short circuit of the mobo will cause a massive overload of the PSU.  An overload protection circuit will also turn off the PSU. If this protection fails, the PSU will overheat and burn.  The overload protection of the PSU is self re-setting, as soon as the PSU is cool enough.  This is the experience you had when you turn on the system the second time and the same symptoms shows up, i.e., LED’s went on for a second and turned off.

12.  What will be the troubleshooting procedure for a tripping PSU?

To troubleshoot a tripping PSU, you need to go back to bare minimum with your peripherals and at the same time to unmount the mobo off the case.  Place the mobo on top of a non-conductive material preferably its box and then connect the PSU, video card and a stick of ram.  Power up and;

If the PSU trips off; unplug the PSU from the wall outlet and disconnect the power connector off the mobo.  Get a paper clip and work it out in a big “U” shape.  Connect one of the case fans to the PSU.  Using the paper clip short these two wires of the power connector, the green wire and any other black wire (see picture).  Plug in the PSU to the wall receptacle and turn it on.  If the fan rotated, then the PSU is working fine.  You might want to try another mobo.  If the fans turns on only for a second and turned off again then the PSU is faulty. 

 

If the system powers up you have a short circuit of the mobo to the case.  Remount the mobo to the case, while carefully watching the standoffs are properly located.  Use plastic standoffs as much as possible with the exception of maybe one or two copper stand offs located by the power connector side.  

 

13.  Why does my system works perfectly with 100/100 FSB but then will not boot when placed at 133/133 FSB?

This is a very common problem with the ECS K7S5A, so far there are two known fixes for this problem but it’s still not 100%.  The problem could be PSU related or overheating of the Sis 735 chipset.  Others who have upgraded their PSU’s reported to have fix this problem while other reported a fix by replacing the thermal tape off the chipset heat sink with Artic Silver or even regular silicon thermal paste.

14.  Why does my system works perfectly with 100/100 FSB but then will not boot when placed at 133/133 FSB?

This could also be a PSU related problem with this mobo.  Two fixes have been reported to work, one is to upgrade the PSU and the other (applicable only to regular Athlon TB) is to compensate the low Vcore by raising the Vcore on the CPU.  To raise the Vcore of the Athlon TB CPU close all the L7 bridges using a 2B pencil.  For Athlon XP CPU, some have reported a fix by replacing the thermal tape on the chipset heatsink.

15.  Is there a procedure I can use to modify my PSU to raise the output voltage of the +3.3V and +5.0V rails?

OCworkbench does not endorse any modifications to be made with the mobo or the PSU to raise the output voltage of the +3.3V and +5.0V rails.