I wanted to ask this to fellow 650 owner,
While reading an epub (a calibre-converted cbc comic book) in SD card, the screen suddenly turns to sync icon, and a while later returns to home page.
My current page apparently is not saved, as I go back and see that the page is resetted to the last time I opened it or even marked as unread when it is my first read.

The book is in SD card, class 4 4GB.

This is my second 650, I am giving it to my sister this christmas so I am loading it and setting things around, and test it. My own 650 is currently being borrowed by my gf (yeah I admit I am using my sis' 650 now, shamefully T_T)
so I can't test it with my own reader.

I read the same epub with my own 650, and I never experienced the above situation, BUT I only used my internal memory.

I wonder if it is a SD-related problem?

As I said in the title, the problem is intermittent. I read 50 comic epub in the past 3 weeks and I experienced it about 5 times.

Any thoughts?

If you see the sync icon, it means the reader detects a card change erroneously. If I were to make a guess, I'd say one of the electrical contacts in the card reader is flaky. A bad electrical contact would make the reader think the card has been disconnected and reconnected immediately after. Either that or the card itself is dodgy.

If I were you, I'd try to wiggle the card from side-to-side while it's in the reader, to try to reproduce the problem. You can also try to spray some contact cleaner inside the card slot, and onto the card's connectors (contact cleaner is available at your local electronic components store), and finally, the simplest solution, try another SD card.

Good luck with your problem.

Another possible scenario if it is not a loose contact is that the FPC connector (the thin plastic ribbon with electrical contacts) that connects the removable storage daughterboard to the mainboard came loose. Carefully open the reader and inspect the contacts on the SD/MS slots and the tightness of the FPC ribbon connection. Here's a service guide for the PRS-600, which hopefully is similar enough to the 650:

http://www.ereaders.nl/prs-600.pdf

And if you're still under warranty, rather than opening it up, you could return it to the store...

thanks everyone for the kind replies.
@Fastolfe: I can't reproduce the problem by wriggling the card now, but I tried getting it out and in back again quickly while reading, and yes it showed the same after-effects.
Then I remembered some days ago I get it out and clean the heads.. No problem since then, none yet..
That must be it.

@jashsu: thanks but I hope I would never resort to that. Not while my warranty haven't expired.

@elcreative: This is a to-be-gift device so it's too late for that.

@jashsu: thanks but I hope I would never resort to that. Not while my warranty haven't expired.

I've never returned anything in Japan before, but if you have a grace period to return/exchange the product to the store then I would definitely go that route first.

On the other hand if it becomes a matter of sending it to Sony to repair, then I would seriously consider trying simple fixes first. For most low value consumer electronics, RMA departments tend to set up a rotating refurbish pool, where they take in your defective product and immediately send out a refurb. They can then triage your item over time and add it to the refurb pool if it is repairable/restorable.