Inspiron 3847, PSU light is flickering green, no power on

[LongAsICanSeeTheLight]

Had a power outage the other day.  Once power was back, my Inspiron 3847 would no longer boot. No power at all. No light on power button. PSU had green light, but was dim and flickering / pulsing a bit.

I followed the PSU test from this page: https://www.dell.com/support/article/us/en/04/sln285154/how-to-troubleshoot-a-no-power-issue-on-your...

Steps tried:

• Opened up the case, and unplugged the PSU from all components. I plug in power, and light is full bright, solid green.
• When I plug in the 24 pin to the motherboard, it goes back to dim and flickering. (Motherboard was disconnected from everything else at the time)
• Swapped out the motherboard with another of same type. Light still dim and flickering.

The motherboard I swapped it with was a used one, and supposedly tested and working. So it's possible that one was also bad, but that doesn't seem likely, right?

Does this lead me back to a PSU issue?

[JOcean · Accepted solution]

It does lead back to the PSU. The only way to know if the PSU is bad is to replace it with another PSU that is known to be working. Possible you have another bad MB but not likely. So far you have done all the correct steps to diagnose the problem. Remember that with the PSU disconnected from the MB there is no load. It is only when connected and a load is on it that the problem could occur.

Also make sure you pull everything from the motherboard when testing. That includes RAM and GPU. You should get a beep from the system if no RAM is detected. Unless of course the PSU is bad.

[RoHe]

Have you tried clearing BIOS on either board?

1. Power off, unplug
2. Press/hold power button for ~15 sec
3. Open case and remove motherboard battery (check Service Manual for details)
4. Press/hold power button for ~30 sec
5. Reinstall the battery (Time for a fresh CR2032 3-volt coin cell battery? ~$2)
6. Close up and connect only mouse, monitor and keyboard
7. Reboot

[LongAsICanSeeTheLight]

Good suggestion on RAM and GPU. I wasn't aware of that. I'll try it out.

[LongAsICanSeeTheLight]

I tried a couple of the procedures recommended above.

• Removing the RAM, and powering on. No sounds at all. No sign of any power.
• Tried the "clearing BIOS" procedures with new battery. No go.

I'm awaiting delivery of a PSU. That will be next step.

[LongAsICanSeeTheLight]

Replacing the PSU resolved the issue. Thanks everyone for suggestions.

[JOcean]

Great to hear and glad we could help!