determine failure mode of power op amp with microscope? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: December 12, 2023, 09:04:24 am
content: I have a power op amp in a can that failed on a channel. (APEX)Not sure if it was me or DOA.I can open this guy up.Realistically could I find any failure modes with a simple microscope?I thought maybe bond wire.I also have a thermal microscope/magnifier from a DIY seek thermal cam (4x).Could that help me ?I just wanna know the cause of failure

author: moffy
author_rank: Super Contributor
timestamp: December 12, 2023, 09:18:26 am
content: Had some high voltage hokey puck SCRs fail, and we opened them up and it was easily visible where a high voltage arc had developed, which gave us the mode of failure, over voltage. Try it and see, and if you want a second opinion you can always post a picture.

author: coppercone2
author_rank: Super Contributor
timestamp: December 12, 2023, 09:21:04 am
content: ok maybe its worth while then, but this is a low voltage high current one.the test I did is a voltage follower. one side don't workI have little fixtures n stuff for the seek thermal I made out of some scrap steel and articulating arms so you can put it on a c able. I hoped to find what is getting hot

author: magic
author_rank: Super Contributor
timestamp: December 12, 2023, 09:28:04 am
content: High energy mishaps may leave signs like fused bond wires or molten metal on ICs.Low energy events like MOSFET gate dielectric breakdown from ESD, probably nothing obvious.

author: coppercone2
author_rank: Super Contributor
timestamp: December 12, 2023, 10:51:36 am
content: its the weirdest thing, I heard a buzzing from near the PCB when it was powered off 2 days ago. i spent 4 hours cleaning my bench to try to find anything that can make noise but its not there. like loud. weirded me out. got everything off the bench and then put the overloaded shelves back on the bench and its totally full againthat's why I wanna take the can apart to see if some weird shit happened in there too. it has 1000uF on the board before regulators but IDK. i thought a beetle of some kind was under something, but no evidence of anything. maybe the contactor under the bench for the power strip, but I never heard it do anything like that before, or a MOV in a power strip or something. bug huntbut it sounded like it came right from the damn pcb. or a sneaky 3d print figurine came to life and its messing with me. i lost a tiny little hydralisk a while back and watched ds9's 'one little ship' recentlymy work bench is about to get germanlast time I had this much confusion was like 10 years ago with a mysterious explosion sound (the only thing left to check is the rigol 1052e, everything else probobly got taken apart and inspected by now)

author: liaifat85
author_rank: Regular Contributor
timestamp: December 13, 2023, 12:34:22 pm
content: A thermal microscope could help identify thermal anomalies, hotspots, or temperature variations that might suggest overheating or localized thermal stress. So, it may or may not detect the exact reason of the OP-AMP's failure.

author: coppercone2
author_rank: Super Contributor
timestamp: December 13, 2023, 02:11:49 pm
content: well I tested the PCB rails and the inputs with an oscilloscope for spikes I don't see anything suspicious/damaging with the power supplies I used.I got another one. The challange of opening the package is daunting. I think I will just put another coin in the slot machine before trying to cut this thing open. too much work. the process is stressing me out