Computer turns on the off again repeatedly every 30 seconds with no display or beeps

[Warmageddon22]

Hi i recently changed the motherboard in my computer to a Gigabyte GA-EP43T-USB3 board as the other motherboard died, with a Core 2 Quad 2.4 GHz Q6600 CPU, i have tried everything that i have read in other posts similar to this one, (e.g. changing graphics card, ram, taking out CMOS, new PSU, new CPU, reseated CPU, checked cables, tried motherboard out of case to prevent short circuit, etc.) But to no avail all i keep getting is it turns on for 30 seconds or so the turns of and repeats with no display, i also tried each component separately in a friends computer and they all worked, so now i am at a loss, any ideas????

 

[R_1]

is there a speaker hooked up to the front panel connector labeled speaker or spk or similar?
there should be a speaker hooked up there, this speaker is the main diagnostic feedback device. when the POST fails the speaker will beep, short, long, repeats, depends on the problem encountered during post. (Power On Self Test)
5 short beeps pause repeat usually means no memory detected. (my board anyway)
any speaker will work I have used a speaker from a stereo and some spare wire.

If there is a speaker and you are not getting any beeps, run this quick test. Remove all the RAM from the motherboard, turn on the system, if the motherboard does not spit out the beep code for no memory (check your manual for exact beep codes) then the motherboard is dead, in my experience. I have never seen a good board not respond to no memory.

 

[Warmageddon22]

is there a speaker hooked up to the front panel connector labeled speaker or spk or similar?
there should be a speaker hooked up there, this speaker is the main diagnostic feedback device. when the POST fails the speaker will beep, short, long, repeats, depends on the problem encountered during post. (Power On Self Test)
5 short beeps pause repeat usually means no memory detected. (my board anyway)
any speaker will work I have used a speaker from a stereo and some spare wire.

If there is a speaker and you are not getting any beeps, run this quick test. Remove all the RAM from the motherboard, turn on the system, if the motherboard does not spit out the beep code for no memory (check your manual for exact beep codes) then the motherboard is dead, in my experience. I have never seen a good board not respond to no memory.

Hi i did as you suggested and i got a power error beep code (just short continuous beeps) so i can assume that the motherboard is good then?, and it is a power supply issue, i also checked my power supply and noticed that pin number 20 on the main connector is not there but in the motherboard manual the same corresponding pin on the motherboard requires -5V could this cause the power problem.

 

[R_1]

I would say the board is good.
piece at a time from here.
power supply, motherboard, CPU, keyboard, GPU and a single stick of ram. (assuming you have no onboard iGPU if an i series or an AMD APU remove the GPU too). try for a post. if you get a post shut down and add another part (another RAM stick), boot and check for POST. Rinse, Repeat.
if no post try the RAM in a different slot or try a different stick. make one change at a time and test for post until the system is built.
the speaker will help

pin 20 is optional on newer power supplies (ATX-2) with 24-pin connectors
http://pinouts.ru/Power/atx_v2_pinout.shtml
https://www.lifewire.com/atx-24-pin-12v-power-supply-pinout-2624578

 

[Warmageddon22]

I would say the board is good.
piece at a time from here.
power supply, motherboard, CPU, keyboard, GPU and a single stick of ram. (assuming you have no onboard iGPU if an i series or an AMD APU remove the GPU too). try for a post. if you get a post shut down and add another part (another RAM stick), boot and check for POST. Rinse, Repeat.
if no post try the RAM in a different slot or try a different stick. make one change at a time and test for post until the system is built.
the speaker will help

pin 20 is optional on newer power supplies (ATX-2) with 24-pin connectors
http://pinouts.ru/Power/atx_v2_pinout.shtml
https://www.lifewire.com/atx-24-pin-12v-power-supply-pinout-2624578

I have tried everything but still no POST all i get is the power error beep code, i also checked the power requirements for everything and it totals around 480W and my power supply is a FSP RA550W.