Hi
I have a 600va PCM UPS i was using it with a big battery and soon i realized my load was overheating the mosfets. so i decided to increase the heat sink. but as i returned everything back the mosfets just started blowing. i got some new mosfets and tried to check where i may have done a loose joint or soldered wrong but even the new mosfets blow up. now am hooking up a small battery which does not have much current so as to test what could be happening. luckily the mosfets dont blow up but the board switches off upon pressing the in button. I don't use it with the mains u just charge my batteries with solar and use it with the ups. i have been removing and testing the A733 and C945 transistors one by one using a multimeter but they have the same characteristics.
All the resistors look ok. I checked with the schematic available online BNT v1.1 and seems ok. but still cannot figure out where the short is. Also replaced the LM317 voltage regulator but still no luck.
Now what else can i check?
All the resistors look ok. I checked with the schematic available online BNT v1.1 and seems ok. but still cannot figure out where the short is. Also replaced the LM317 voltage regulator but still no luck.
Now what else can i check?