> Anyway, on the assumption that something is wrong with the SD card, are > there are known good SD cards I can buy locally? > > The list at http://elinux.org/RPi_SD_cards is not helpful, and seems to be > full of contradictions.
Make sure your power supply is good.
> I have read stories of people spending lots of money on SD cards and > finding none of them work, so am a bit nervous about doing this myself.
People buying lots of SD cards and none of them working? What's the one common thing amongst all those SD cards? The power supply.
*** Absolutely correct! My local Computer tech said to make sure whether the ssd card is 3.3 or 5 volts. If you plug a 3.3 volt card into a 5 volt power supply it will cook instantly hence people having so many cards instantly die. If you plug a 5 volt card into a 3.3 volt supply it will be flaky and possibly die over a short time. The unfortunate thing is, not one of the cards I checked has the voltage marked on it and usually there are no instructions or specifications included. Check your power supply hard drive connector voltage. Go to manufacturer/supplier web sites and verify the voltage of the card/s you wish to purchase. Roger