Dr Ivan D. Reid wrote:
Anyone have any data on the reliability of Oyster? My PP has
started playing up lately on the buses; first an occasional beep and red
light, followed by either a successful second swipe or the driver waving
me through. Tonight on the U1 at Brunel the reader wouldn't even produce
an error so I had to fork out cash. Coming back from Uxbridge on a U1,
the first swipe produced no response, the second a red light and a
"Communication Failure" message. I was diving into my pocket for cash
when the driver suggested I try again, and on the third attempt it worked
perfectly.

Your oyster is on the way out, my first one lastest about 5 months,
started going intermittent, and about a week later didn't register at
all. I kept in my jeans pocket.

Get a replacement one (for free, or it should be) from a tube counter.