You would need to contact the place where you purchased it to have them assist you with getting the unit sent in for repair as there appears to be a different issue that is causing it to fail that is beyond the extent that anything we can do for you, or you can do for yourself.
If you bought it in China, you can contact the Central Music Co who are the PreSons Repair and Service and Support center in China.
However if you bought it in another country and brought it to China with you, Central Music Co is not obligated to assist and may charge you for repair services even if it's within warranty of the original purchase date.
The Answers system is not designed to work like a forum, if this answer does not meet your needs, then please open up a support ticket at http://support.presonus.com
so a support tech can assist you and/or contact the PreSonus office in your region to lend assistance.