Well, i have the same problem with wm1a, i cant solve it.
Some other guy with the problem had luck updating the firmware to an older version.
Some other guy, sony told him no replacement for you since your out of warranty, send it to repair center, and repair center said sony doesnt want to give board programming software, so he was stuck in between.
I got it used from japan, and sony wouldnt take it from me, sony japan said i must send it from within japan and i dont live there, i have no one there.
Very frustrating given the money spent on them, very bad service, since it seems a fault with the device.
On the other side alot are enjoying their devices with no problems
I don't see how you can actually blame Sony Japan for their service, Sony has always operate after service warranty, in a regional way, and since you purchased a Japanese version, you were expecting warranty issue, if ever it had a problem, They are willing to repair it if you are within warranty period, but you have to be in Japan for their service center or, mail in repair is only available for domestic version or sent from a local address, if you purchased a tourist version, you should have a international warranty card for worldwide warranty service. Even without warranty, you can pay for the repair, in Japan or in your home country, they are willing to accept it.
I have both the ZX300 and ZX2, both the Japanese version and both purchased in Japan, nothing wrong with my ZX300, but I had my ZX2 change the LCD screen (it was my problem, the damage was my fault) and since they was going to do the repair, I had them to change the battery as well, it cost me a total approximate 22000 YEN (USD 200), a lot, but every time in Japan for holiday I'm willing to spend money, even if it's for repair, in my home country, Hong Kong, the same repair cost less, but I'm not will to pull the amount of cash out.
So that you know, why the ZX300 cost so cheap, the quality is not up to the standard of the ZX2 or the WM1A/1Z.
No hard feeling, just trying to explain a bit on how Sony do their work, and so you know, I will never have any Sony stuff repaired in Hong Kong, the worst customer service, same with Samsung. That why I'm willing to pay more and have them done in Japan.
I'm in Japan this November and will be visiting the Sony center for some spare part, I have already contacted them in advance so they have the parts available during my visit.
On a side note, have you contact Sony in your country, some times they will repair out of good will if it's still in warranty period for free.
