[Fixed] Agilent DSO3102A blown PSU, unknown IC (Exploded)

[DavidAlfa]

I heard a loud BANG coming from the testing area, 10 minutes later this scope arrived for repairing  .
The main SMPS IC completely blew apart, sadly coudn't find the flying pieces carrying the identification, neither found schematics for it.

After analyzing the circuit implementation, it seems to match a TOP242-250 series, so I ordered a TOP250 (The most powerful one).
However it would be great if someone could share a picture!

[DavidAlfa]

After discovering the 3102A was a rebranded Rigol DS5000, searched for old Rigol schematics, hopefully that part was also used in other series.
Found the 1052 series hand-drawed schematics:
http://rigol.codenaschen.de/index.php/Schematics



So Indeed, a TOP247! (Just slightly lower power rating than the TOP250)

[franksretrolab]

I know this topic is almost a year old, but I wanted to add a photo of the component so that if someone else is looking for this info, they would have it.
The part appears to be a TOP246.

Thanks

[DavidAlfa]

Thanks. For reference, the TOP250YN worked fine.

The scope was still repaired only a month ago, took a full year for the purchasing department people! (They're are terribly lazy!)

[slugrustle]

Any idea why this part broke?  Was simply replacing the part sufficient to repair the scope?

I've seen a failure in a flyback converter based on an IC like this where the following appeared to have happened:
1. RCD clamp diode failed short, leading to TOPSwitch internal MOSFET overvoltage and failure.
2. Internal MOSFET is now shorted while supplied through the flyback "transformer" from rectified AC mains.  The transformer would quickly saturate.
3. The clue was the fact that the drain lead on the TOPSwitch had vaporized. 

[DavidAlfa]

Nothing else was found. Maybe just old, or a mains spike.

[DavidAlfa]

@franksretrolab, here're the requested connector voltages, plus some waveforms.

[franksretrolab]

Thank you so much.
This is fantastic!
I appreciate it!!