I bought this ∧ 30V 10A dc supply not too long ago (4 months maybe) as a secondary unit. Hardly used at all and already dead. I have an older similar unit that's always worked great so I am not sure if this one was just a lemon or from a bad batch. At first it seemed to work good, I used it for brief 3/5v loads once in awhile. Til last week I decided to use it more often (mostly 14V 2a loads, nothing fancy or over demanding) Pretty much soon as I started using it full time I started seeing it have issues with dropping power. It would slowly drift from 14V down to 0, Then come back full. This would happen about every 10 minutes. After a few days of monitoring this behavior it finally decided to die completely by blowing the main fuse. Wife told me I should buy a better one so I quickly agree'd, set the dead unit on the junk shelf and found a great deal on this guy:




After the replacement supply arrived and got settled in, figured I finally take a look at the busted one. The 2 mosfets are shot for sure, completely shorted. Other then that I'm not seeing anything out of the ordinary. Power supply's are not really my forte tho so I figured I'd see if anybody had any other suggestions on things to look out for while I'm waiting on the replacement mosfets.

 

My first guess would be overheating of those MOSFETs. Is that cooling fan working?

 

My first guess would be overheating of those MOSFETs. Is that cooling fan working?

Hello,
Yes the fan did come on and seemed to work well. I'm thinking the mosfets are probably bad replicas or either one of them was just defective.

 

Replaced the two blown 13N50's with new 15N50's and its working good again.

 

Amazing how clean the signal is from the tek power supply vs the cheaper ones I have. A large cap on the output of the generic one helps a lot but still not as clean. I don't really need to do too much where noise interferes but there was a few times awhile back it was hindering me a little and I would always blame my usb pico scope. Rather happy that unit in original post failed and I ended up grabbing a proper supply.

here's a short I did the other day while I was using both.

And....
Since I posted the other one, here is the inside of the tek: