LG RH1777 region hack gone pear shaped

[Aussiebear]

A few months ago I got the region hack for my region 4 machine and everything was rosey, a couple of weeks ago i try to play a reg 2 disc and it's gone awol, not only will it not play reg 2, it wont play reg 4 either. Any suggestions?

[fzabkar]

I don't think it will help, but here is a service manual:
http://www.jordansmanuals.com/Default.aspx?Brand=LG&Product=DVD-VCR&Model=RH1777