From half a year has the burden of proof, so I immediately turned down at the Customer Service of the manufacturer. This does not answer me on my 2 months ago (and repeated every 2 weeks) Asked request. To date I have received no feedback and the part can be expected to give the recycling center. Too Bad. I do not buy more units of ViewSonic.
Nevertheless there 3 points. The instrument has up to the time met my requirements. Buy I would not but it definitely.