Welcome to the new Schneider Electric Community

It's your place to connect with experts and peers, get continuous support, and share knowledge.

Close
Important Announcement: WELCOME to the new Schneider Electric Community! Community is now no longer part of Exchange, and is now rebranded under se.com. If you have any bookmarks and links saved, we request you to update them to ensure that you continue accessing our community from this new location. For any issues that you might encounter as part of this change, please reach out to SchneiderCommunity.Support@se.com, and the team will help to get your issues resolved.
Invite a Co-worker
Send a co-worker an invite to the Exchange portal.Just enter their email address and we’ll connect them to register. After joining, they will belong to the same company.
Send Invite Cancel
82165members
349752posts

BACK-UPS PRO 420 MOSFET Burning Problem, please somebody help....

APC UPS for Home and Office Forum

Schneider Electric support forum for our APC offers including Home Office UPS, Surge Protectors, UTS, software and services and associated products designed to share knowledge, installation, and configuration.

Solved
xman123_apc
Cadet
0 Likes
1
110

BACK-UPS PRO 420 MOSFET Burning Problem, please somebody help....

This was originally posted on APC forums on 12/18/2011


Hi,
I`m new here and my english is not good but I`ll try to describe all details related to my problem at best possible way and I hope that somebody will help me in this problem...

I have old APC BACK-UPS PRO 420, and for some reason on this ups stop to work, after checking what is problem I see that main transformer is burned and one mosfet (q34 - schematic -> http://www.upsclub.org/schem/APC/218/218F5S5.pdf ), because I have one more same ups with some other problems I replaced this parts and when I start this ups to work on battery (unplugged from main power source) all working fine, without any problem, no heating no bad sounds, nothing, all fine...I leave this ups to work few minutes on battery and all was good...after this I plug it to 200v ups switch normal from battery to main power source and continue to work normal, no heating, no bad sounds...but after ~10 seconds ups stop to work, stop with beeps, fet q34 and q33 start to heat abnormal, from transformer I have some very bad sound like overloaded and I must unplug it from all power sources (now again don`t wont to work on battery, same sounds like on main power and after few seconds trying it switch to overload and stop to work)...

After checking mosfets again I see that Q34 is again burned (not q33), I replaced it again and again same test but again on same way same mosfet is burned!!!

Do you know why this mosfet burning after ~10seconds on main power source??? Without any load, without any heating of this mosfet (until it burned)...

All schematics you can see here: http://www.upsclub.org/schem/APC/218/


Accepted Solutions
BillP
Administrator Administrator
Administrator
0 Likes
0
110

Re: BACK-UPS PRO 420 MOSFET Burning Problem, please somebody help....

This reply was originally posted by Chris on APC forums on 12/20/2011


Unfortunately, We do not troubleshoot at this level on these units. Though it may be possible to replace components, we wouldn't be able to give you any advice as to how or any advice why a specific component isn't working as we don't trouble the individual components. If anyone outside of APC does have any experience with this, feel free to help xman123 out.

See Answer In Context

1 Reply 1
BillP
Administrator Administrator
Administrator
0 Likes
0
111

Re: BACK-UPS PRO 420 MOSFET Burning Problem, please somebody help....

This reply was originally posted by Chris on APC forums on 12/20/2011


Unfortunately, We do not troubleshoot at this level on these units. Though it may be possible to replace components, we wouldn't be able to give you any advice as to how or any advice why a specific component isn't working as we don't trouble the individual components. If anyone outside of APC does have any experience with this, feel free to help xman123 out.