WS-8681 - power problem

[kodi]

I have WS-8681 for over two years. Thanks to this forum I fixed the childhood problems (rain sensor) and now the station is working reliable. However one day I had enough of waking up and seeing "lost sensor contact" message in the log, caused by discharged batteries every 10-11 days. So I built a nice power supply with high efficiency DC-DC converter, 12V 7Ah Pb batery + 1.5W Maplin solar panel. It lasted 3 months and 4 days. Just got the batery from the compartment and it was completely discharged (6.5V...). So I started to dig into the Net and found that normally people are getting like 5-6months easily on two AAs! So I was digging a little more and found a short post on one of the forums that there was a batch with faulty resistor on the transmitter, so it was causing much more power drain than normal. As I don't have schematics, can someone tell me which resistor was faulty (or with wrong value) and what it should be replaced with?

[Super-T]

I get over a year on standard AA alkaline batteries.

[kodi]

Thanks, Super T... I found an entry regarding 15months on Lithium batteries. Still looking what's wrong with mine.