Desktop Motherboard Dynamic G41 - Suggestion

[dspok]

Hello,

Sometime I used to repair desktop motherboard also.
Today I found there is low voltage in PSON pin which is less than 1.5v, which is not turning on because there should be 3.3v, when i short green-black cable on SMPS, wow the display comes.

I checked 5v STANDBY voltage which is ok after than I found there is AMS1117 which should be voltage regulator in my opinion. In other board it just converts 5v STANDBY to 3.3v STANDBY for SIO.

I changed new AMS1117 still there is less than 1.5v, changed SIO chip still SIO is generating less than 1.5v to PSON.

Can anybody assist me to find out the exact problem.

[ktmmotocross]

Re: Desktop Motherboard - Suggestion

have schematic?

[dspok]

Re: Desktop Motherboard - Suggestion

@ktmmotocross
I didn't find schematic of the said board it is Dynamic G41 motherboard.

[dspok]

Re: Desktop Motherboard - Suggestion

dual post............

[Agent24]

Re: Desktop Motherboard - Suggestion

Is the AMS1117 actually a 3.3v type?

Is it getting the correct input voltage?

Is there a short or low ohms on the output\what it is powering?

[tiak]

Re: Desktop Motherboard - Suggestion

Hi,if AMS1117 have 3.3 v on output and you haven't that on power switch pin ,so check smd transistors near the power switch pin.(check AMS1117 temperature,it is hot?)
goodluck

[stj]

Re: Desktop Motherboard - Suggestion

did you trace the pin back incase there is a diode or resistor or something inline with it?

[dspok]

Re: Desktop Motherboard - Suggestion

thanks everybody, AMS1117 is itself generating low voltage it getting correct input voltage though, even I replace with good working one.