Not really dead, and not 100% saved but here goes:
Dirty.
Fungus.
Everything else is smooth as you like, focus is buttery and aperture is smooth and precise, both to set and during functioning.
Disassembled everything. Nitrile glove and the supplied base cap took reasonable care of the name ring. Three screws underneath for the name ring's collar.
Three screws underneath for the element assembly block. I marked one of the screw holes with a minuscule line to ensure it was being returned in the correct orientation, though I doubt that matters a huge amount given this couldn't be done for every element removed. Careful! There are little washers with these screws. They are minute, and look very easy to misplace!
'Labelled' the area initially with the tweezers but quickly replaced that for an unused toothpick.
Various aspects of the elements removed, usually with use of a lens spanner to remove retaining rings. Thereafter cleaned up with 6% hydrogen peroxide, isopropanol then naphtha, finishing with a small, clean microfibre. Nastiest chunk of fungus in the element block below!
Thereafter it was reassemble. The frontmost element is marred slightly by the fungus that was there. No mycelium left though! However, not a dust free environment by any stretch of the imagination, nor did I have my rocket blower handy (silly me). Ergo, it is now dustier inside than it was. I
will address this in due course but the idea for today was to sort out the fungus, after receipt today. Considerably cleaner than it was and not bad for £10 + P&P! Looking forward to trying it out!
Note: Someone had clearly looked to take apart the front at some point during this lens' life. Note the mark under the 'A' of Pentax?