Eaton 5S UPS - Page 1
Forum section: electronics / repair

author: C-47
author_rank: Regular Contributor
timestamp: December 17, 2023, 06:39:49 am
content: Have had an Eaton 5S-700 for a number of years, no problems, however several days ago, got the heated burning smell from the unit while in standby, a quick check indicated the case area around the transformer was very hot. Opened it up and the circuit board showed nothing visually outstanding, the internal fan checked as working on 12v, put back together and it appears the fan is not operating when the unit warms up, question, does anyone know where the temperature sensor is for the fan. Very aware of the nasty surprises inside. Thanks, Alan.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 17, 2023, 03:39:42 pm
content: could be something screwed on the heatsink

author: C-47
author_rank: Regular Contributor
timestamp: December 17, 2023, 10:43:15 pm
content: Thanks, a close look around the heatsink area reveals nothing, I thought there maybe something under the yellow heat shrink tubing, but nothing. Having recently read about capacitors being near heatsinks, the photo reveals they couldn't get it much closer, while I've been onto Eaton's web site, no schematics are available, as the unit is 8+ years old, it's maybe time for retirement as don't want to risk it.

author: 5U4GB
author_rank: Super Contributor
timestamp: December 18, 2023, 01:25:34 am
content: As a general comment, most of Eaton's UPSes output what they euphemistically term a "modified sinewave" which I'd never let near sensitive electronics (some older APC? UPSes were notorious for getting closer and closer to a square wave as the batteries ran down), so if you do ditch it then go for something with a pure sinewave output, which will also have things like active PFC and just a better design in general than the low-end stuff. Cyberpower do decent UPSes with all of that that won't break the bank, particularly if you get a used one and swap out the batteries, you can get them for under $50 with dead batteries.

author: C-47
author_rank: Regular Contributor
timestamp: December 18, 2023, 02:16:25 am
content: 5U4GB thanks for the input, worth considering.

author: fmashockie
author_rank: Frequent Contributor
timestamp: December 18, 2023, 02:57:42 am
content: Quote from: 5U4GB on December 18, 2023, 01:25:34 amIf you decide to go this route, watch out when looking for low-end pure-sine wave UPSs. I'm speaking specifically about APC's BRxxxMS (BR1000MS, BR1500MS) series. I mention these because they are likely one of the first UPSs that pop up when you search for one on Amazon, google, etc. The large inverter/AVR transformer in these is made very poorly. I have performed a HI-POT test on one of these transformers brand new and it fails miserably (I put it on my Youtube channel). There is a fix for these UPSs - just replace the transformer with a different make (I also document that kind of repair here)! But these transformers can cause these UPSs to fail catastrophically in ways that could likely cause a fire.

author: C-47
author_rank: Regular Contributor
timestamp: December 18, 2023, 04:02:33 am
content: Thank you fmashockie, interesting indeed. Being in Oz and wanting to buy locally, the APC brand does not appear near the top of a search. Where I worked before, APC brand were not preferred due to many failures and the video provides guidance on some of this.

author: 5U4GB
author_rank: Super Contributor
timestamp: December 18, 2023, 07:58:16 am
content: Quote from: fmashockie on December 18, 2023, 02:57:42 amFor people who haven't seen the original discussion that's referenced in the video, it'shere. Yup, definitely avoid the low-end APC stuff.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 18, 2023, 11:22:26 am
content: apc have many problems, eaton no schematics .... so far

author: fmashockie
author_rank: Frequent Contributor
timestamp: December 18, 2023, 03:55:20 pm
content: Quote from: 5U4GB on December 18, 2023, 07:58:16 amLet me start by saying I don't pretend to possess a fraction of Dr. Carlson's experience/knowledge. But his explanation that the transformer failed because it has alumnium winding falls short for me. Yes that might explain the poor connection from winding to the leads, but aluminum-winded transformers are used frequently without any issue. Also, the transformers I tested did not have any issue with the connections from the windings to the leads.

author: johansen
author_rank: Super Contributor
timestamp: December 18, 2023, 06:54:38 pm
content: Quote from: fmashockie on December 18, 2023, 03:55:20 pmgiven that the batteries are self contained in the ups, it doesn't really matter if the transformer failsi've taken a lot of them apart and they just have a lot of mylar tape between the primary and secondary.

author: C-47
author_rank: Regular Contributor
timestamp: December 19, 2023, 06:23:54 am
content: Update: thanks to all for the responses. I obtained a replacement Powershield UPS locally, because to get one of the suggested ones from the other side of Oz is a 7 -10 day ordeal, so was able to get stuck into the Eaton. Removing the heavy duty cables attached to the heatsinks noted a level of oxidation between it and the lugs on all 3 (sorry no photos) cleaned up by scraping and put back together for a try and its back to normal, the fan runs and it at least, for now, keeps cool. Logically that shouldn't make any difference, but can't argue with the electrons, so will keep it a backup / spare. One of the earlier photos shows 1 of the cables. Thanks