Rigol DP832 - smoked channel 1 [FIXED]

[Howardlong]

Well, I managed to fry my Ch 1 today when showing my nephew what happens when you put an electrolytic in the wrong way round.
PSU to 32V, 3A. 10V 100uF cap, wrong way around. Pop, magic smoke. But PSU starts saying it's overvoltage on Ch 1.

Sad to hear. Was the cap fully discharged?
Cap may presented close to short circuit situation for a PSU. How can a short circuit bring down lab grade PSU? It is a complete fail

I would assume it was discharged, I pulled it from a bag of caps that I've had for quite easily 10 years. The end state of the cap was as expected, loud pop, a nice load of smoke, bit of a red flash, plenty of fibrous stuff knocking about in the vicinity with a bit of capacitor offal hanging onto the croc clips. I'd tried a 47uF 16v one a couple of minutes earlier, but that just got a bit fat, I wanted some action, and I got it, just a bit more than I wanted and not quite what I expected.

The more I think about it, the more I think that this is a fail. I took the opportunity to do a firmware update this morning, to 1.13, but irrespective, I won't be trying the same stunt anytime soon.

[mcinque]

I popped a cap with my 832 with a crappy usb charger here using 13.8VDC 3A with no damage to CH1, so I guess it could be a defective unit. Otherwise me too would have a smoked channel, don't you?

[Howardlong]

FWIW, I couldn't find locally a CEP80N15, so I used an STP80NF12 which while slightly lower on the Vds specs (120V vs 150V) is 80A rather than 76A on the Id, max power dissipation is the same, and otherwise spec-wise it appears good enough. Just tested it at full smoke on Ch1, seems fine, but I'm not intending to do a reverse cap test anytime soon.

[giosif]

Sorry to revive this old thread, but I thought I'd add this information for future reference: the 0.02 Ohms SMD current sensing resistor is an Isabellenhütte SMT Series and its size is 2817.
More details can be found here (also attaching the .PDF, in case it gets pulled from the manufacturer web site at some point in the future):
https://www.isabellenhuette.de/fileadmin/Daten/Praezisionswiderstaende/Datenblaetter/SMT.PDF

[tangram]

Thanks Skimask.  Just did the reverse voltage on a partially charged car battery and had exactly the same result.

I think the diode is still intact spookily enough, but the sense resistor, the fuse and the track blowout is consistent.  I'll swap out the diode anyway, 'cos it must have taken a smack, even if it's hanging in there.

Was foxed by the resistor, so glad you were able to confirm the value, otherwise I would have bought a range of 'em and spent hours swapping out and testing.

Cheers 

Followup:

Managed to get everything up and running again.  There was enough of the fried track leading to the diode that, with a little judicious prodding, more or less got it together again and soldereed the two broken sections together.  I guess the bad news is that with 2-3mm of solder bridge here, that section of track will be able to carry a huge load.  Something somewhere else might crap out if I'm stupid enough to reverse polarity a car battery again.   I needed to replace three components:

The Diode (D4?) I replaced with SCHOTTKY DIODE 45V 8A AXIAL - 80SQ045NRLG
Blew a PCB (F3) Fuse, which I replaced with FUSE BRD MNT 7A 125VAC/VDC AXIAL F6123CT-ND

both of the above from digi-key.

The sense resistor (R52) was a pain in the arse to replace.  I found a supplier in the UK who would sell me the part, but he wanted me to pay £99.99 per unit for 5 off, or buy 5000 of the bloody things at a much reduced price.

Found a suitable replacement eventually:  Shenzhen LCSC Electronics Technology Co., Ltd. had the parts.  LCSC#: C466590  Mfr.#: SMT-R020-1.0  $1 USD each, so not too bad, though the UK postage was fierce!

Having fixed the track,  sweated the new resistor in place and swapped out the other busted bits, my DP832 is back up and running.  Needed a recal' unsurprisingly, but it's back in full trim :-)

Thanks again to all the peeps who've added their tuppence worth to aid in the repair.