APC ES700 UPS

[DaveL59]

So I picked up one of these cheap-ish, reportedly making a constant tone when powered up. Figured it may be just the usual replace battery and perhaps replace 4 capacitors so why not...

Replaced the very dead battery with a Yuasa that I have kicking around that I know is good. Noted a burnt smell when I opened the battery bay and thought that's maybe not good but no external signs of heat damage so swap battery and press on. Plug in and press the power-up button. Green light and a buzz for a couple secs, sounds good 🙂 Then 10 sec later it turns off and gives a constant beeeeee. Tried dead-heading the unit and same again, hmmm.

Now a common fail on these seems to be the small 22uf electrolytic caps, a cheap and easy fix, so ordered those yesterday and they arrived today.
How to Fix APC Back-UPS ES Constant Beeping Problem | Nicu Surdu

So I've opened the casing to make a start and pulled the board... oh dear!

that's not good! 😮 Explains the overheated/burnt smell lol and of course the magic smoke has well and truly left the building in this case.

No idea if this as been overloaded in its past life but I guess I'll be ordering a IRF2805 MOSFET as well then. Might consider replacing all the electrolytics while I'm at it, save having to revisit this board again, IF I can get it working again that is. At least the 2805 is only around £5 so perhaps worth a go.

Ho hum, worth a punt for a few quid but a bit more work than I'd planned on. Did I really need another UPS? No not really, was more thinking along the lines of one for my daughter as she gets frequent blips and a unit of this type would have been ideal.

[DaveL59]

hmmm checking the other caps they are all 85C rated which isn't great in kit that will run pretty warm when the inverter is running. I'll replace these then with 105C rated ones and higher voltage when I get around to doing this I think. No telling if any of the on-board fuses also blew, something else to check in case those need ordering too.

Question is if its even worth doing or just obtain another unit that isn't pre-fried, that tho would be a gamble too unless I spend around £60 for one from an UPS refurbish outlet which at least would be guaranteed working and with a new battery.

For sure these type of unit don't seem as good as the old SUA SmartUPS model which rarely needed more than a battery and perhaps voltage tweak on the charger side. I have read that these ES units can fail on power surges so could be just that, not a good sigh in that regard tho, perhaps.

Edited January 21, 2021 by DaveL59

[DaveL59]

ok so I figured I'll have a go and throw a few more pennies at this one. Just ordered the below.

6x 22uf 25v -> original is 16v
2x 4.7uf 450v
1x 330uf 35v - original is 25v
1x 47uf 63v -> replace with 56uf 63v
3x 4.7uf 50v - original is 25v
IRF2805 MOSFET

All replacement caps will be 105C versions. WIll revisit this page once the bits turn up and I've swapped/tested. Fingers crossed 🙂 

I do have a later ES700 that works just fine hence thinking this should be simple, yeah right lol. At least these spares will be pre-insurance for that one if needs be, assuming that this failed one doesn't come back to life. Might be worth me taking a pre-emptive look inside the working one and perhaps swap out at least the 22uf caps in that one too.

[DaveL59]

so today the MOSFET arrived, the caps a couple days earlier

out with the board, clean up the mess with some isopropyl and cotton buds

Looks like the SMD components are all intact, hopefully none have failed and triggered the death of that MOSFET. I cut the exploded MOSFET away and then removed the electrolytics. Didn't bother ESR testing to see which if any had failed as I figured may as well replace the lot while I have the board apart. So new 105c caps as per list in previous post and MOSFET duly installed:

 

now for the acid test - will it power up correctly? So install an old Yuasa 7AH battery I had spare and...

let there be light 😄

So on power up it does its self-test and then settles just fine. Unplug the mains supply and it carries on as it should do. Not yet tested it with a load but can't see why it won't carry on working correctly. Happy with that result I think, this one can go into service in the shed once there's a dry day, should be just fine to hold the remove cctv DVR and cameras up for a wee while during power trips.

[DaveL59]

Loaded the PowerChute software and hooked up to USB to see what's what

Gradually picking up charge so I'd say this one's sorted, at least for now 🙂 

Only tested with the drill battery charger hooked up to it and it does continue with the mains disconnected which kinda proves the invertor side is working so the MOSFET replacement is good. Don't really have any handy higher power stuff to connect to it as everything here is pretty much wired into bigger SmartUPS units.

Did notice that the PS software crashed with a stack/heap error on the second disconnect, not ideal as that's the latest issue. Seems it interferes with the network-USB control software too but that's fine as it'll be uninstalled once I finish testing. I use the network version for the SmartUPS since they have manglement cards in them for monitoring.