UPDATE: I got side-tracked last week, but I'm back on this again now - and it seems that the battery isn't available as a standalone item out here. (ETA: I think I could order the battery if I was in the states, but a Sony Pro-Parts rep told me they won't ship it outside of the US.) So I'm now getting the entire CK-093 board shipped here from Singapore. It'll cost me 1300 NTD (about 40 USD) and it should be here next week. I'm not at all sure how easy it would be to install this board -- it may well be trivial, or it may require special arcane knowledge/techniques/tools. I dunno -- so I may have the Sony service people do it after all. There was a bit of confusion (on my part) about how much extra that would cost: it's either 30 USD or 70 USD for labor.

Anyway, looking at it one way, 40 bucks for a new board seems very reasonable. On the other hand, all this trouble and at least 70 bucks to replace a freakin battery seems insane.

Happy Ending
 

The board arrived yesterday. The tech guy said it shouldn't be any problem for me to install it myself, so that's what I did. It was delicate work -- man, even the screws are tiny, never mind the flimsy, slightly stiffened 'plugs' at the end of those flatwire strips -- but I got the old board out, put the new one in, put it all back together again without any pieces left over... and hey, it all seems to work fine!

So far I haven't seen that annoying 'this is not a Sony battery so I'm shutting down again' problem either. It was always an erratic problem though, so fingers crossed on that one.

Anyway, I couldn't/wouldn't have done it without access to those exploded PD150 schematics and the tech manual -- so thanks again for your help you guys!

Also, from now on I'm going to store the camera with a charged-up external battery pack in place. I figure this will reduce the demand on the internal battery and thus help to extend its life. Although if anyone knows any reason why this might not be a good idea, please advise!

That's great, Norman! Congratulations on a successful repair, and thanks for checking back in to keep us up to date.