Q5 4K switches to 4:3 instead of maintaining 16:9 and causes powertrips

[napapon 365]

Hi there My name is Napapon
 I recently upgraded my TV to a 4K one and proceeded to change the Q5 resolution to 2160p30.  But this resolution seems to output 4:3 format when I restarts the box.

I have no problem with 1080p for many months, just 2160.  Anyone has this problem too?  I bought my box from taobao so I believe it is a China set.  Also, it occasionally causes powertrips when I power on.

My TV automatically detects the output from Q4 as 4:3 although I can force the TV to show 16:9 under Q5 2160 resolution but I think it is not solving the root cause of the issue.

Anyone knows why 1080 can maintain 16:9 but 2160 can't?  Has it got anything to do with the refresh rate?  Thanks in advance.
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