TS-239 with UPS not accessible after power outage

[auato]

Hello,
At a minimum power outage, even less than one second, although I have a UPS "APC CS650" connected which seems to promptly act avoiding the NAS shutdown, NAS gets to be inaccessible both via webpanel and SSH. So it is not accessible anymore but you can ping it and also QFinder is able to find it in the local network. The UPS looks like in a good shape but honestly I don't know how to check if its performance are or not in the correct ranges. When the power failure occurs, UPS acts immediatly but I can also hear a different speed from the regular noise from the internal HDD (that most likely means that the power failure or the even a fast drop of voltage has been propagated in some way from the UPS to the NAS). I am struggeling unsuccesfully for months What can I do before buying a new UPS? And what type of check I can do on NAS to figure out why it is still running and available for ping and for QFinder but it is impossible to access for a log in? Thanks

[dolbyman]

use a power meter to see if the ups is still supplying correct voltage

if the voltage drops or the frequency is off, get a new ups


side question, the nas is not set to immediately go into protection mode..right ?

[auato]

Hi dolbyman,
No, it is not. I have only set "the system will enter "auto-protection" mode after the AC power fails for 2 minutes".
Good idea, I can also check power supply output of my NAS with an oscilloscope in DC.

Thank you, I'll let you know

[auato]

Hello,

I performed some tests in the afternoon as suggested by @dolbyman and unfortunately it does not seem a problem coming from UPS:

• no voltage drops in AC -->https://youtu.be/2CwBErfA3lQ and DC --> https://youtu.be/LpKwHwsXuwQ;

• powerchute selftest is OK --> https://youtu.be/N-A8LETkmE8;

So I am getting worried the fault is due to something in my NAS
I also attached a short video about what I listen from the HDD when a short interruption happens --> https://youtu.be/Em7STUJfzCo
I really appreciate any comment so, let me know please.

[dolbyman]

it could be an issue with an aging power supply not liking the artificial sine wave (you could only scope that to find out how it looks)

you could test if there actually is an error with the UPS trip feature

- connect the NAS to a regular wall outlet but keep the UPS USB plugged in
- simulate a power failure on the UPS (unplug it)
- see if the NAS still behaves that way even though it's connected to a regular power outlet and not the UPS

[auato]

it could be an issue with an aging power supply not liking the artificial sine wave (you could only scope that to find out how it looks)

you could test if there actually is an error with the UPS trip feature

- connect the NAS to a regular wall outlet but keep the UPS USB plugged in
- simulate a power failure on the UPS (unplug it)
- see if the NAS still behaves that way even though it's connected to a regular power outlet and not the UPS

with the test above any interruption doesn't affect the NAS. With an oscilloscope I could verify the sine wave but just for curiosity because now I have to take a decision as the filesystem is corrupted again and I don't have another UPS for other tests. What can I add is that the UPS supplies also a Small Form Factor computer which is not affected at all and looks like as a well protected device when an interruption occurs.

[dolbyman]

With the test above you have identified the UPS inverter output power as the likely culprit.

The fact that you have a scope at your disposal, probably makes you better suited to troubleshoot any further than me.

See if the DC output has some weird ripples
https://www.youtube.com/watch?v=eVB_n4t57Yc

[auato]

OK thank you @dolbyman. Tomorrow I'll check the waveform on AC output but especially the ripple on the DC line because another suspect can be the AC/DC power supply because the same UPS also supplies a Dell Optiplex 790 without problems.

[auato]

Today I spent my free time to perform some other tests and finally I fixed my issue.

Checked the outgoing waveforms (with UPS running and without UPS): https://youtu.be/BhckfIWeDkk you can see a pure sine wave when the backup is not running.
Then I focused on the NAS Power Supply and as suggested by dolbyman I checked the ripple. https://youtu.be/RWqqp4mzMfg
Replacing the power supply with that horrible ripple, with another one temporarily adapted for the test, the problem is gone

Thanks dolbyman for the support and tips

[dolbyman]

good work .. glad you fixed it