Hi, time for an update. 2 weeks in service from new and a 'Low battery transmitter 1' error. I have two consoles and both show the same. Entering 'setup' mode on the console, cycling through the options and exiting clears the alarm until the ISS sends it again. Otherwise, I think it clears at midnight. Anyway, I cleared the alarm and about 10 minutes later it came back indicating that the ISS is still reporting a low battery. I went on the roof with a meter and managed to open the battery case and poke the prods in without actually removing the battery. It read 3.17V so is clearly not dead. Prior to touching it, I watched the LED - nothing. I then removed the battery to check the contacts. Sure enough there was a liberal coating of the grease everyone has mentioned. I replaced the battery. Once back on the ground, I reset the console and so far, a week later the alarm hasn't reappeared. In conclusion, it seems to me that the CPU in the ISS 'thinks' the battery is low when it's not. Removing it and replacing it is telling the CPU that it's been changed wan actually the same battery is reinserted. All I can do is wait. If it happens again, it goes back. Will keep you posted. Those of you who have been changing batteries, try replacing the same battery. My bet is that it will have the exact same effect. Either way, the unit is faulty. Mine hasn't stopped working though. John