Powerware 9120 Online UPS

[danielegat]

Re: Powerware 9120 Online UPS

I'm a new member. I have a problem whit my 9120 6kva. on display appears the message "O/V low"; infact when it begins working it's ok, but after 20 second the ups goes in bypass and the message that I said, appea.
Can somebody help me? thanks

[magdtron]

Re: Powerware 9120 Online UPS

I have something different with powerware 9120 3000 w , it works perfectly without unplug ac cable - backup mode - when you plug the ac and begin to change over commercial AC, i hear very loud desirable sounds, i cant wait to expect the worst, have to unplug the ac cable at once

[Behemot]

Re: Powerware 9120 Online UPS

Bad relay maybe?

[morphis]

Re: Powerware 9120 Online UPS

Hi just repaired a Powerware 9120 700VA that was showing 'DC BUS FAULT'.

At first I pulled C14 and others ( C10, C40 C42 & C48 as they are in close prox. to heat sources )
I measured the capacitance of the pulled caps, But the were all within 10-15% of there rating. So I though bummer this is not going to be easy as I don't have an ESR meter.

But then I found this video "#135: Measure Capacitor ESR with an Oscilloscope and Function Generator" and last year I purchased a Rigol MSO1104Z-S so after a couple of minutes setting up and testing known good and bad caps as a test. Was able to very quickly go thru and test the pulled caps.

So C14 was like 89uF so thats within 11% of 100uF and on a 20% spec cap it still looked ok to the DMM but its ESR was off the charts.

The rest of the caps were perfect.

So if you have a 'DC BUS FAULT' and you have measured C10 and C14 and you still think they are ok, REPLACE THEM.

Replaced: C10 with Nichicon 100uF 63V 105ºC and remounted the nearby diodes slightly off of the board as its looks like they get nice and toasty.

[morphis]

Re: Powerware 9120 Online UPS

Hi just repaired a Powerware 9120 700VA that was showing 'DC BUS FAULT'.

At first I pulled C14 and others ( C10, C40 C42 & C48 as they are in close prox. to heat sources )
I measured the capacitance of the pulled caps, But the were all within 10-15% of there rating. So I though bummer this is not going to be easy as I don't have an ESR meter.

But then I found this video "#135: Measure Capacitor ESR with an Oscilloscope and Function Generator" and last year I purchased a Rigol MSO1104Z-S so after a couple of minutes setting up and testing known good and bad caps as a test. Was able to very quickly go thru and test the pulled caps.

So C14 was like 89uF so thats within 11% of 100uF and on a 20% spec cap it still looked ok to the DMM but its ESR was off the charts.

The rest of the caps were perfect.

So if you have a 'DC BUS FAULT' and you have measured C10 and C14 and you still think they are ok, REPLACE THEM.

Replaced: C10 with Nichicon 100uF 63V 105ºC and remounted the nearby diodes slightly off of the board as its looks like they get nice and toasty.



I also have a Powerware 9120 1000VA.
I replaced C10 and remounted the diodes the same as the 700VA just to be on the cautious side.
Theres not 'Fault' but I think it might be the same as magdtron its making a to so nice sounds while charging the batteries.

- The sound disappears after a Battery test for awhile but then returns after about a 30 secs.
- Also disappears when Mains supply is removed.
- In HE (High Efficiency) mode or Bypass Mode the sound still exists if Mains supply is connected and the batteries are being charged.


Also I found out that the Powerware/Eaton EBM connector is 5x shrouded 4mm banana plugs in a moulded connector.
So I'm going to design a 3D printed plug to hold off shelf shrouded 4mm banana plugs, Custom EBM

[Behemot]

Re: Powerware 9120 Online UPS

Yeah that's exactly what we keep repeating here - you won't tell bad cap with just capacitance meter. If you want entry-level professional ESR meter/capacitometer, I can supply ya. You can use O-scope but that's really for telling way-off caps only.

[feil]

Re: Powerware 9120 Online UPS

hello,
someone still reading this?^^

i have also an ups like that, with the DC Bus Fault Error
i have now changed the 2 caps c10 c14 for trying, but still doenst work,
someone any suggestions what else it could be?

regards
clemens

[goodpsusearch]

Re: Powerware 9120 Online UPS

I would check every capacitor on it with an esr / capacitance meter.

[feil]

Re: Powerware 9120 Online UPS

I would check every capacitor on it with an esr / capacitance meter.

i dont have something like that

any suggestions witch one i could try to replace?^^
regards
clemens

[goodpsusearch]

Re: Powerware 9120 Online UPS

It could be any capacitor that may have gone bad without bulging.

You can buy something like this:

http://www.ebay.com/itm/New-Quality-...IAAOSwo6lWOFOW

http://www.ebay.com/itm/2015-LCD-128...YAAOSwBLlVLeOR

http://www.ebay.com/itm/2015-LCD-128...cAAOSwPgxVMBnp

[Behemot]

Re: Powerware 9120 Online UPS

Just remember these AVR meter toys can not measure in circuit, they have no protection agains charged caps and those without casing can be potentialy lethal.

I got entry-level professional ESR/capacitance meter with relay protection if you want something of decent quality. It is possible that soon I'll also add advanced version of that AVR thing to my offer.

[goodpsusearch]

Re: Powerware 9120 Online UPS

It is highly unlikely that he is going to spend 35€ + for a dedicated esr/C meter. These ~10€ AVR tools are the best option for someone who just wants to fix something / a casual hobbyist.

[Behemot]

Re: Powerware 9120 Online UPS

You never know…there are dozens of ppl here who started repairing stuff regularly as soon as they acquired the knowledge.

[goodpsusearch]

Re: Powerware 9120 Online UPS

That's true!

[feil]

Re: Powerware 9120 Online UPS

can you recommend some esr/C meter ?^^
so round about 0-100 dollar if possible.
can i test with them condensators without desoldering?
until now i only have repairdes thing where i have seen the bad caps, but im interested to do more than that^^
regards
and thanks. clemens

[Behemot]

Re: Powerware 9120 Online UPS

I am distributing the ESR Micro v4.0si. You can buy directly according to current exchange rate for CZK, or for fixed price at Bonanza.

Direct competitor for it is the Atlas ESR70 from Peak, though I think it is somewhat more precise and has faster cap discharge, it has smaller range and costs as much as twice the price.

[alltvrepairs]

Re: Powerware 9120 Online UPS

Hi,
Its my turn now

I have the 5KVA model with same DC Bus Fault. Have thoroughly followed this thread. My main board is more complicated. I have changed the capacitors marked in RED in the DC-DC section.

Anyone was able to find a schematic? Its a pity not being able to fix this old but good UPS.

PSDR-1112NN

Thanks!

[ToryStreetLights]

Re: Powerware 9120 Online UPS

Anybody still listening :-) I have a Powerware 9120 700 watt version that appears to be working perfectly but not charging the battery. The MUR460 gets very hot and had shorted, it's 1k 5 watt power resisistor load gets very hot, as does the chopper Fet driving it and the small Fet further on in the chain. Replacing the MUR460 with similar diodes immediately creates their demise with a short again. There doesn't appear to be any circuits around for this machine which I find very unusual, as I have worked at board level for over 50yrs.

Any observations will be gratefully accepted - Thankyou in advance :-)

[Behemot]

Re: Powerware 9120 Online UPS

Just a general idea since I don't even know how this one looks like.

The CPU is usually powered from the same stand-by PSU and sometimes some small transistors this road go bad so try to check that out.

[ToryStreetLights]

Re: Powerware 9120 Online UPS

Just a general idea since I don't even know how this one looks like.

The CPU is usually powered from the same stand-by PSU and sometimes some small transistors this road go bad so try to check that out.

Thank you for your observations I will look along that track. When operating under normal conditions the battery has a permanent drain of 300 ma until it is exhausted when the UPS shuts down.