UPS Problem

[johnc12]

Helow guys,

Well as a new guy here in office I don't have any knowledge in troubleshooting.... After the busted monitor, now my problem here is the APC ES 500 model BE500-PH. I can't find any schematic that could help me and APC refuse to give me one... My problem is this, my UPS wont start and I found out that one of the MOSFET (IRF740) is burned. I replaced it with a new one but the unit still wont power on. Hope you guys could help me troubleshoot. I have 3 more UPS, the same unit and similar problem, unit wont turn on.

I will really appreciate any help that will come. If you have question, don't hesitate to ask. 

 

[ante1]

Hi john,

Is this IRF740 working solo or is it paralleled with more 740

 

[johnc12]

I see, the irf740 is in parallel with 3 irf740 also. I can see that it is found near the ceramic caps and the source. There are also some burned resistors and transistors near the mosfet but it is too small to determine, and I think they are defective too.

I would be glad to see you're APC 500 schematic and see if it matches on my unit here.

Thanks ante.

johnc

 

[ante1]

Ok, you got it. Here are all APC diagrams I have available!
I hope one of these will help you find the problem.

 

[johnc12]

hehe. Ante, I tried to check the UPS using you're diagram but it shows only little similarity on the pcb. The mosfets, resistors and caps are hard to find and not the same as irf740. My supervisor and I decided to indicate the problem and declares the unit defective and will be replaced... thanks ante... 

 

[ante1]

Just don

 

[johnc12]

yes i wont... Ill place it on my archive for safety.... Soon when Ill be working on APC Ill be able to fix that problem... rar