SMX2000LV displays "No Input Voltage" when plugged into a live circuit

[RBond]

My APC SMX2000LV has new batteries as of 3/7/24 and was working beautifully until just a week or so ago when it started to shut down (turn completely off) on it's own... not associated with any power fluctuations. Now, when I start it back up, the read out says No Input Voltage.  I've measured the current at the plug at 121v AC.  "Feels" like there is possibly some voltage detection circuit issue...  or a faulty capacitor to blame... but I'm guessing. Any ideas on how to proceed with diagnosis?

Cheers!

RB

[Teken]

Two basic things to check is the rear breaker hasn’t tripped. If so press the white button a few times to make sure. Next what is the current state of the outputs on each bank?

Using the LCD verify they indicate on and not off. Even if they show a on state toggle each of the output banks on-off-on.

If you do not hear any relays clicking during this process the relays are welded / failed.

Lastly, please upload the active / past error logs on this unit. You can also read them off the LCD and reply back what they are / were. 👍

[RBond]

Teken... sorry this took me so long to reply... Life.

Ok... so the breaker was not tripped. I pushed it several times. Not to mention, the problem is not on the output side of the unit... it's on the input side. That white breaker button is to protect the output overload only... right?

I can toggle the 3 output groups off/on successfully and I can hear the relays working.

And I have attached the log file dating back to late April... right around the time I installed the new batteries.

I DO appreciate your looking at this!

Cheers!

RB

[Teken · Accepted solution]

You can try a brain dead procedure to see if this clears the system or changes the unit’s behaviour.

Brain Dead: Shut down and remove all connected loads. Remove AC Mains from the wall outlet. Disconnect the battery cartridge from the unit.

Press and hold the power button until you hear a click / beep. You may not hear anything at all . . . ☝️

Apply AC Mains to the system without the batteries connected. Press the power button and wait for unit to start. 

What does the system indicate as the active fault?!? It should be the missing battery cartridge.

If no, please call out the active fault / error from the LCD. If the system declares a missing battery (this is good) install the battery cartridge into the system.

If the system asks you to confirm this is a new battery cartridge say yes. Input the current month and year of the install.

At this point initiate a manual Self Test via the LCD. The unit will either pass or fail the POST (Power On Self Test).

If the system passes the Self Test connect at least 30% load. Initiate a battery calibration either through the LCD / NMC.

Please report back where the fault starts and what the problem is. 👍

[RBond]

Thx, Teken... that seemed to do the trick 😉

After disconnecting everything and pressing the power button there was no audible click or beep. However when I plugged it into the AC Mains I heard the unit click (2 quick clicks actually) and that was a good sign 😉

Powered up (battery still disconnected) and indeed it reported: No Battery Connected.

I connected the battery, entered the new install date and ran the Self Test: Passed

Applied a 37% load and ran the Calibration Test: Passed

Seems it's back up and functioning!  I'm curious now what as to what may have triggered the problem in the first place.  Could it be related to some kind of thermal overload issue?  What behavior happens when the unit gets too hot?

Cheers!... and thanks very much for your time and direction!

RB

[Teken]

At this point I would monitor the unit over an extended period of time to insure all is well. You’ll want to conduct a few static and dynamic tests on the system at random intervals to see how it behaves.

Pay close attention to how many times the system goes into battery only mode. This happens either when the AVR setting is out of range or if the electrical power is considered dirty.

You can adjust the power quality from normal / good to reduced, low. The upper and lower transfer voltages can also be adjusted for a wider input voltage too.

Why are we doing this?!? 🤔

Because olde SMX series units had weak relays! As such, over a long period of constant (relay) transfers the unit will see the infamous (Relay Weld) fault / error! 🤦‍♂️

Hence it’s imperative that you tests how the unit behaves and listen carefully to the relays upon start up, battery transfer, and AVR compensation. 

As you heard the system will make a double click indicating closure of the input voltage relays for 120 VAC. 

This is one of those static tests you’ll want to conduct when and where time permits with due care with load and without. When the system is under connected load this is considered a dynamic test of the system.

Essentially both tests (Static / Dynamic) tests must be done to validate the system is fully operational and can be counted on during a lights out / grid down event or when the AVR circuit is activated due to dirty power. 

Essentially you’re going to pull the plug for whatever duration you feel is acceptable to mimic a loss of input power.

If the  (internal relays) are failing the behaviour you saw will happen again until such time the system will declare either an internal fault or relay weld error. ☹️

Monitor both the NMC logs for system operation and power quality. If you have a NMS (Network Monitoring System) up and running via SNMP / Syslog keep an eye on the long term historical performance and power quality.

Circle back in the next few days, weeks, months as to how the unit behaves. Along with any changes you’ve made to sustain a solid system.

Lastly, if the previous reply helped resolve the problem would you please consider marking that answer as a solution so it can help the next person asking the same! 

Rock On . . . 👍🍺

[RBond]

... super helpful info here... thx again. I'll keep an eye on it 👁

Grid power where I am is not as stable as it should be. I'm in a remote rural area and get lots of outages and brownouts... hence my need for the UPS.

One last q... if the these units had "weak" relays... is that something that can be rectified by replacing them with better quality ones?

Cheers!

RB

[Teken]

Yes, it’s done all the time just do a Google search and on YouTube. Any electronics repair shop can replace them. If you’re handy and have decent soldering skills you could do the same.

It takes longer to remove the main board out of the housing then to replace the relays! 🤦‍♂️☹️

NOTE: The above information does not apply to a unit being used in a business setting or hardware under warranty! ☝️ Any components inside the unit should be repaired & replaced by a certified technician.

As a DIY person the risks of damaging the unit or causing other unrelated problems are high if the repair isn’t done properly.

[RBond]

... thx again, Teken!

As it turns out I'm fairly adept with soldering... I do a lot of vintage audio gear repair and restoring 😉

When searching for replacement relays (I believe we're talking about the 5 black relays on the motherboard... and possibly the white one too?) is there a different part # I should look for, or search for the same part number?

... and, yes... I'd certainly take full responsibility for negative any outcomes! 🙂

Cheers!

RB

[Teken]

Going off memory depending upon what specific model relays are inside the unit. You’ll find only that specific relay vs a suggested replacement on Mouser / DigiKey / Other.

I know when the fleet of units were R&R the relays were not the OEM parts. But ones with higher durability ratings with respect to temperature, number of cycles, and wider voltage range. 

I don’t recall whether it was the SMX vs SRT models where the relays had better anti arcing capabilities. 

Let me know what you find and how things turn out if you decide to follow through in the relay replacement process! 👍🍺

[RBond]

Teken... a followup to this thread...

Today, this same APC shut down on me again.  This time I was sitting in front of my computer when it happened... so I have a bit more detail to add to our discovery.  The unit went completely dead... instantly. No period of switchover to the battery at all... and the unit's display went dark. Much as if the unit had no battery connected and was simply unplugged from the wall.  I did another Brain Dead restart and it's back up again and I grabbed the log from the last 24 hrs which I've attached.  I'm not experienced enough to know the subtitles of what the logs refer to, but there is an entry that says "Battery Not Installed Properly".  I'm pretty sure the batteries ARE installed properly... but perhaps there is an intermittent battery connector? I'm guessing, of course.

If you have a moment and can take a look at the log I'd very much appreciate it 😉

Sorry to drag you back into this one!

Cheers!

RB

[Teken]

Hi RB,

A few thoughts and considerations for you to ponder. I believe the unit has some kind of internal hardware fault such as the relays we discussed before. Over the long term if this unit is something you want to keep for whatever reason given your skills in audio repair this may be the fix.

Having said this, I did notice based on your logs this unit has a (AQ) serial number which I believe indicates a refurbished unit.

I also noticed your NMC and UPS is pretty behind in firmware releases. If you’ve read any of my replies as it relates to firmware you’ll quickly see I don’t recommend updating anything unless there is a specific reason such as resolving a bug, security, or feature enhancement.

As updating the firmware in the NMC / UPS has a risk of bricking the two pieces of hardware. ☹️

Updating the NMC firmware is less risky vs the UPS however if all requirements are in place. The UPS firmware is another matter all together though and if you read enough threads on the internet or this forum you’ll quickly see the results are more than 50% that it will fail and brick the UPS hardware! 👎

Why am I saying all of this?!? 🤔

There was a bug as it relates to battery disconnection along with how the unit should behave during a transfer from AC to battery.

Updating the firmware on both units may resolve something or nothing at all if it’s a hardware related issue as I believe this to be. 

Let me know your thoughts and what direction you think works for you. If you want to update the firmware I can provide you some reference material for the best outcome that isn’t well documented in the firmware update procedure from APC. 

NOTE: Before you do anything else would you kindly make the following changes. In the power and quality settings change the sensitivity to low and the upper and lower voltage transfer to the (widest) input voltage. 

Please enable SMTP for email notifications on the NMC. This will provide quicker notification and insight as to when there are active faults / errors present.

Prior to the unit shutting down.

Lastly, there are two logs can you provide the data log that shows the various metrics of input / output voltage, frequency, battery, etc.

Cheers! 👍

[RBond]

Thx again for your consideration!

I agree that the unit's behavior would point to some kind of hardware issue... and if the relays are a known issue, I may just go a head and replace them anyway.  Nothin to lose... right? If this were a piece of audio gear I'd probably start looking at failing capacitors as the culprit... but without a schematic and the understanding of the circuitry, I'd be guessing.  As for the relays... they aren't "welded"... as I can hear them working... but I suppose they could be "weak" and switching over intermittently... or being told to do so by failing components... 🤔

"There was a bug as it relates to battery disconnection along with how the unit should behave during a transfer from AC to battery."

... this sounds suspiciously appropriate to my unit.  Are most of the refurbished units repaired as the result of a  consistent or inherent problem? 

Ultimately, I'd love to resolve the issues and keep the unit, as these things aren't inexpensive 😉 ... so my immediate reaction is to try the firmware updates to both the NMC and UPS.  That being said, the unit is unreliable in its current state... so the risk of losing it altogether is low.  The firmware update reference materials you spoke of might be useful in helping me make that decision... if it's easy for you to attach those, that might be the place to start 😉  Much like computer OS software, I assume that this older unit will only be compatible with firmware versions up to a certain point (?)  Is the unit smart enough to recognize firmware versions that are not compatible?

What would cause the error log to report that the battery is not installed properly? ... and shut completely off at what appears random intervals?

I'll change the settings according to your instructions... and grab the I/O voltage metrics. Incidentally, the unit shut off a second time yesterday (right in the middle of a recording session!) and I haven't restarted it back up yet... so I don't have the logs for that event.

... thx again, Teken... sorry this is becoming a deeper dive than anticipated 🙄

Cheers!

RB

[Teken]

Hi RB,

A few more things to check and consider before any firmware is updated. I don’t have high confidence doing either will resolve the issue.

Having said this there are two things I wanted to test and for your consideration. There have been reports of SMX / SRT Series units with EPO (Emergency Power Off) incidents when the EPO isn’t even connected?!? 🤦‍♂️

The purpose of the EPO is to allow a person to quickly and rapidly shut down a target UPS system. There is no other physical method for a complete shutdown of the system besides the EPO or removing the AC Mains & Battery Cartridge.

If you still have the phoenix connector which may be green, blue, grey. Wire it up with a dual lead cable and turn the unit on.

While the unit is fully operational short the two leads together. The unit will immediately shutdown when this is done.

If the EPO operates as expected this leads to my other steps to check. In case you have a none APC Serial cable it can shutdown the system!

If there are ANY cable’s including the USB cable disconnect both. Monitor how the unit behaves with nothing attached as it relates to communication (USB / Serial) cabling.

Another test is to disconnect the battery cartridge. Let the system operate like this to see if the same behaviour is seen. Obviously if you have a grid down event the unit will shut down. But you’ll know if it’s caused by a power outage because the unit will restart once AC Mains is restored.

Which you should double check your system is programmed to restart once AC Mains is restored.