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.