Optoma UHD40: Image at 60Hz

8dsfj1921

Member
Hello,

I have what I think is an issue with an Optoma UHD40 whereby the image appears doubled-up, with the second instance of the image offset by a few pixels in the vertical direction. This affects both the supplied image via HDMI, and the on-screen Optoma menu items. Issue only apparent when the projector is provided with the following input signals:
  • 1080p @ 60Hz
  • 2160p @ 60Hz
When provided with the following signals, picture quality is great:
  • 1080p @ 50Hz
  • 2160p @ 50Hz
Tested with an Amazon Fire 4K stick, directly plugged into the HDMI (4K) input of the projector, and selecting different output options in the Fire display settings. Also reproducible with a Nintendo Switch (poor image at 1080p @ 60Hz, but no option to change refresh rate there).

Some pictures below, showing doubling-up and vertical shifting of the horizontal border lines (and text) when source is 60Hz. Compared with inputs at 50Hz, showing no doubling-up and a crisp image. The green "test pattern" generated by the projector is pin-sharp.


I have sought technical support from Richer Sounds, who walked me through confirming that 3D is disabled (didn't realize I had 3D support, but certainly all the 3D options are greyed out and disabled). They in turned contacted Optoma, and the explanation that was relayed to me is that this is actually expected behavior, something along the lines of 60Hz is for supporting the US market (I'm in the UK).

Whilst I understand there are differences between US/UK-European broadcast frame rates, my understanding is that's a moot point - the projector should be capable of displaying 60Hz input at these resolutions if provided with such a signal. Am I off the mark here? Indeed some of my devices (e.g the Nintendo Switch) only seem to offer 60Hz output, so are practically unusable with the projector.

Everything I can find suggests these resolutions should be supported at 60Hz:
Datasheet: https://www.optoma.co.uk/ContentStorage/Documents/49e99ce8-b494-4b26-8790-1e6c005e0000.pdf
Manual: https://www.optoma.co.uk/ContentStorage/Documents/e009649e-2f61-40e3-b6bf-4124e5a5c548.pdf


Does the feedback ring true with anyone? Anyone seen a similar issue?

Thanks.
 

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