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lexx3218, Computer Support Specialist
Category: Computer Hardware
Satisfied Customers: 2759
Experience:  Computer Hardware trouble shooting and problem solving professional.
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I have just replaced the PS with a new Dell PS on a Studio

Customer Question

I have just replaced the PS with a new Dell PS on a Studio 1909. Computer will not power on. It tries, but will not.
Submitted: 2 years ago.
Category: Computer Hardware
Customer: replied 2 years ago.
I have not traced the leads from the power switch to the motherboard yet, but I suspect there is another bad part hiding somewhere, yet I do not suspect the switch.
Customer: replied 2 years ago.
The soft power switch is in a module with the sd card reader with one round cable attached to the motherboard at a Molex connector. All the capacitors on the motherboard at this junction look fine. There is no signs of bulging or any signs of overheating on the motherboard.
Customer: replied 2 years ago.
The same is also true where the DC power connector from the power supply connects on the motherboard. Everything looks good there too.
Customer: replied 2 years ago.
The module with the power switch has mic and earphone ports, 2 USB ports along with the universal card reader. So in Dell terms it is an IO panel.When the unit is plugged in for the first time it does what seems like a self test. It powers up the system fans, flashes the side led for power button then shuts off. When the power button is depressed, the same thing happens, like a self test, then nothing, it shuts right down again.
Customer: replied 2 years ago.
I am thinking now that it is a motherboard level voltage reference that failed likely due to the dubious power supply I replaced.
Customer: replied 1 year ago.
I will be checking the power good signal from the new PS and attempt to trace it to the next component.
Expert:  bbranham3 replied 1 year ago.

it is possible that the bad power supply could have damaged the power switch module or something further. in many cases you will not visibly see damage.

other things to try when you get a no POST test type situation is unplug all optional devices (usb, hard drive, cd/dvd, keyboard, mouse, printer) and try to power on again.

if that does not have any effect reseat the memory modules

if that again has no effect reseat the cpu

Customer: replied 1 year ago.
I may have jumped ahead of your suggestion. First thing I did was remove and reseat memory modules. Cleared USB ports, unplugged SSD, unplugged DVD drive and tested. Same outcome. Last thing I did NOT do is reseat the CPU. I will try that tomorrow. Thanks for your suggestions
Expert:  bbranham3 replied 1 year ago.
thanks for the update
if reseating the cpu does not clear the issue then the issue is either at the button module or the motherboard.
Customer: replied 1 year ago.
I have reseated the CPU, cleaned and added new thermal compound to heat sink, cleaned heat sink for graphics processor, added new thermal compound. Reset CMOS.I am showing a green LED illumination on the motherboard when power is supplied to unit. When power button is depressed, unit powers up, then shuts right down again.If the momentary power switch was faulted, I am assuming it would not power on the motherboard at all. Since the switch is just a momentary short across two pins to start the unit, the switch is seemingly doing the job.Something else is telling the unit to shut down. Any ideas?
Expert:  bbranham3 replied 1 year ago.
i would agree it sounds like a fault in the sensing of voltages from the power supply. Highly unlikely this could be a another faulty PSU, but most likely motherboard failure.
Expert:  lexx3218 replied 1 year ago.

Hello I was just checking to see how everything turned out what is the update please?

Customer: replied 1 year ago.
I have a known good motherboard on order. After reading many forums, there seems to be a common problem just as I have experienced. Since the cost of power supply and motherboard are no longer expensive, I can justify the purchase of a known good working motherboard. I can not buy a working computer for what I have invested in parts so far, plus I am able to troubleshoot the bad parts and replace them at my leisure and will have working spares.
Expert:  lexx3218 replied 1 year ago.

This is very true like I said before in this case it's usually either a power supply malfunction and at times in this situation a motherboard problem. Please don't forget to leave positive feedback for my time and assistance it's how we are compensated for our time. Thank you again.

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