BX900R Solid Tone

[Anonymous user]

I own a BX900R 900VA APC UPS. I've had it for roughly two years now and just last week the UPS failed on me and shut down in the middle of some work I was doing. I instantly thought the battery was at end of life. At my work we use APC UPS's and they roughly last two years there so I thought the same would be true for my home UPS.

So I went out and bought a new offbrand battery (sorry APC I'm on a tight budget right now). I've purchased batteries from this place before with no problems. RBC5.

It came yesterday so I installed it in my UPS. Wanted it to fully charge before using it on my computer so I set it aside without anything plugged into it. After 15 minutes with no load, the UPS shut down again with a solid tone coming out of it. Touching the UPS, it was really hot.

I'm thinking the fan failed on it but I'm not sure. If it is the fan, is there a way for me to fix this without having to send it back? Like buying a new fan and soldering it on?

Using a watt meter device, I'm only pulling roughly 435 watts max on my entire computer system (between 250 watts and 400 watts is normal load). Even when the UPS was brand new, it would only last a couple seconds before the UPS would shut down... like it couldn't handle the wattage. I thought a 900VA UPS could handle 435 watts for at least a minute so I could shut down but I guess not. I was using it for flash power outages which I sometimes get.

[BillP]

yes those specs are correct. i can only guess and by looking at it, it has the same specs. so at your own risk, my educated guess is yes, this will work for replacing the fan in the UPS.

[Anonymous user · Accepted solution]

An update someone might find useful.

I have 2 APC BX900Rs (Back-UPS XS 900), one which failed souding the same solid tone and one with a fan that makes loud screeching sounds. I was very irritated to find that this failure mode is not documented anywhere, and APC simply recommends replacing the entire UPS when it occurs. I pulled apart and disassembled the UPS (the trick is popping off the front panel to get to the three screws under the front panel) and the fan in my BX900R is 40x40x10 but only 12v according to the label.

The fan says: Young Lin DFC401012H, 12v. The spec sheet for the fan says it is 12V, has an input current of 0.09A, and runs on 1.1W of power at 6000 rpm, approx 7 CFM and 26dB-A.

I will be replacing it with a similar 40mm fan that runs slightly slower according to it's spec sheet, but it should push enough air since I run the UPS in a home office environment that usually doesn't get very hot. The stock fan specs a minimum of 5.44CFM so the 6CFM fan I bought should work fine.

I also bought a new battery for the UPS with the screeching fan, since its battery was so dead that the UPS wouldn't even power on to do a self-test. The battery from the UPS with the steady tone might still be good but I can't really test it until the replacement fans arrive. A store in town sells the generic 12v SLA batteries used in the UPS for about $48 per pair, much better than the $95 (shipped) APC charges. The APC batteries aren't anything special, since they just slap APC stickers on generic batteries anyhow (I pulled a sticker off to get the specs off of the battery). My batteries are branded "vision CR1270", 12v 7AH.

Be careful - at least one amazon.com seller is advertising "APC" branded replacement batteries for $78, which is really close to what APC charges for their batteries with the full warranty. But the amazon seller ends up shipping batteries with a sticker that says "ABC", not APC. The batteries work the same but they are not real APC batteries and therefore void any warranty and carry no APC warranty on the batteries. If you want that warranty and don't have a local shop that will warranty their batteries, then you might be better off buying the super expensive APC batteries.

[Anonymous user]

I'll check tonight after I get home from work.

By the way.. the SMT2200 UPS is a BEAST. We are testing one of them right now with our network at work and that thing will power everything we have and then some in a power outage.

I wish the price was lower so I could get one for home use lol

[BillP]

alrighty. depending on what you see there, then you may have a fan failure or something else going on.

[Anonymous user]

Ok sorry it took so long. had the window open right over the UPS so it never got hot until I closed the window lol.

It's four red blinks. It has to be a heat problem because it only started when the window was closed and when it could heat up.

Serial number JB0738013700. I don't have the receipt anymore. Didn't know it had a three year warranty. Bought it about two years ago.

[BillP]

four red blinks? is this the overload LED flashing?

if so, it does sound like the symptoms of a fan failure. a few other posters on the forum have discussed this before on this forum about replacing it and complaining how its not technically user replaceable but some other, unsupported by APC solutions have been discussed that you may want to search for 🙂

without a receipt, your unit shows that it is about 4 years old, so i dont think APC support would honor the warranty for you.

[Anonymous user]

I can't seem to find a replacement fan for this UPS. I understand it's 40x40x10 size. 24 volt. 2 wire. 70mA.

Nearest to those specs I could find is this:

http://cgi.ebay.com/New-Lot-10-Nidec-Beta-V-24V-40x40x10MM-C33903-16-/140348384873?pt=LH_DefaultDoma...

would this replace the faulty fan?

[Anonymous user]

Well I finally got one of those fans on. They didn't come with a connector so I had to solder it onto the pins on the board.

Got the case back together, turned it on, and the fan started right up.

It's a little loud when the fans on full blast but it only goes full speed when the battery backup is on. Normal operation I can barely hear it which is good.

So the UPS is fixed and I saved myself over $100 buying a new one.

Thanks for your help.

P.S. I have 9 fans left. The ebay auction was for 10 fans. Couldn't find someone selling a single fan anywhere. So if anyone else has the fan problem in this UPS, contact me in PM and we can work out a deal to send you one.

[BillP]

along with your solid tone, are you seeing any LEDs (solid or flashing)?