My E3634A Mystery Explosion – WTF!

This is a short follow-up to a video where I was recently testing a Mayyuo M9711 DC Electronic Load (See Here) and I was using an Agilent E3634A Power Supply (which I previously fixed) as a power source. When I put the DC load into pulse mode within a few seconds the E3634A PSU exploded. What I heard was a loud pop, and a flash followed by a loud vibrating 50Hz hum, by which time I was able to reach the power switch and shut it down. I switched to another supply and continued with the test of the M9711 but today I thought I would open up (once agin) the E3634A and see what damage was done and what I found is a real mystery!

Did I imagine it all? Was there beer involved? Who knows, its a mystery!

Hope you enjoyed the video, catch you next time…

UPDATE – I found the smoke source

While tidying up I thought i would have a look at the two power MOSFET’s that failed and found the IRFP260 has a very small but visible smoke vent! I have added the photo’s below, I had to take these under the microscope x10 and x30 to see it. With the naked eye it looks like a light scratch.

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  1. Sabatoge methinks…..

    The halogen lamp, at the end of a long and admirable career has been pushed aside. Quietly watching the new Maynuo squeeze in, it has taken to the dark side. Instead of a direct attack on said digital load, an indirect attack on another in-favour instrument recently receiving far too much attention.

    Yes, a diabolical twist of misdirection….no one even considered the lamp. Hmmm.

    Watson (mike)

    1. Mike, if I understand what you are saying, I agree, while a programmable DC load is very useful, the good old fashioned lamp is a forgotten solution to many load and power related ills and needs. Gerry

  2. You sure Spanner didn’t visit late at night and enable the magic-smoke emitter while you weren’t around???


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