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Topic: What am I doing wrong? 2nd PSU turns on before the 1st. MOBO won't boot. (Read 373 times)

full member
Activity: 254
Merit: 100
Dude

Just use a paper clips and make a jumper,

 grounding 2 gpus together is a no sense to make you buy a add2psu adapter

i've been using paper clips for 1 year, and they are very Good!
full member
Activity: 196
Merit: 100
I have 2 750W EVGA G2 PSUs. They work individually just fine. I have an ATX connector with ground. I plug the main PSU into the main PSU connector which is plugged into the MOBO and then the 2nd PSU into the 2-wire connector for ground. However, when I turn on the PSU's the 2nd starts spinning immeditalty even before I'vev turned on the first. If I then turn on the first the MBO gives an 99 error on the LCD.

I've tried two ATX connectors from different places. What am I missing?

The mobo is set to turn on with power detection. But I assume everyone else's are configured this way too?

Jump start the second PSU which is powering the GPUs first and then start the first PSU to power on the MOB. Try changing the cables and see if it works. If it's not working no matter what you try, I will recommend you to invest in add2psu, it will save you a lot of time and headache.

I actually have an add2PSU, but no free molex to use it. So have to buy another cable for that.... oy. That little thing was expensive and was happy to use just the ATX connector+ground. Alas...

As for jump starting, isn't the concern that the two psu's should be grounded together?
sr. member
Activity: 861
Merit: 281
I have 2 750W EVGA G2 PSUs. They work individually just fine. I have an ATX connector with ground. I plug the main PSU into the main PSU connector which is plugged into the MOBO and then the 2nd PSU into the 2-wire connector for ground. However, when I turn on the PSU's the 2nd starts spinning immeditalty even before I'vev turned on the first. If I then turn on the first the MBO gives an 99 error on the LCD.

I've tried two ATX connectors from different places. What am I missing?

The mobo is set to turn on with power detection. But I assume everyone else's are configured this way too?

Jump start the second PSU which is powering the GPUs first and then start the first PSU to power on the MOB. Try changing the cables and see if it works. If it's not working no matter what you try, I will recommend you to invest in add2psu, it will save you a lot of time and headache.
full member
Activity: 350
Merit: 100
I was going to buy those add2psu connector adapters but honestly i said why bother - I have a few dozen that I just jumped the pins on the PSU so they're powered all the time - I know many probably would advise against this but they've been fine for a month now so I'll just keep them that way. Since they're just powering GPUs and risers so far there has been no issue with them.

I'm slowly replacing them all with EVGA 1600w PSUs but not sure if I really want to replace the rest.
full member
Activity: 196
Merit: 100
I have 2 750W EVGA G2 PSUs. They work individually just fine. I have an ATX connector with ground. I plug the main PSU into the main PSU connector which is plugged into the MOBO and then the 2nd PSU into the 2-wire connector for ground. However, when I turn on the PSU's the 2nd starts spinning immeditalty even before I'vev turned on the first. If I then turn on the first the MBO gives an 99 error on the LCD.

I've tried two ATX connectors from different places. What am I missing?

The mobo is set to turn on with power detection. But I assume everyone else's are configured this way too?
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