Do not dumb here

I saw the above at the end of Curious Marc's latest video:

source: https://www.youtube.com/watch?v=aPIZwqq_W_k

I tried Google translate on a zoom in and got this:

Japanese

so maybe it was a bad translation: dumb instead of dump ?

I remember one of those yellow signs I saw in a hamshack once, something like:  TEST IN PROGRESS  keep your cotton picking hands off the equipment !  something like this:

source: https://storage.googleapis.com/hippostcard/p/234ef24dcee3a13b45e41acafac45cdf.jpg

another example:

source: https://d3h6k4kfl8m9p0.cloudfront.net/stories/L-Uysv.jgSeFdscFRE70BA.jpeg

tech humor: simple and turn down the volume on the laughter.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm