I am not able to fully test this vintage monitor but it appears to be functioning normally from what I remember. The funny green screens you see with the lines in them aren't visible or green or blue from the naked eye it just looks like a normal black and white/blue screen. Curious. And the V hold knob moves the line around only when looking through the camera which is also interesting and those are the photos 2-3.

Brighten knob makes it bright or dimmer. And that's all the testing I'm able to do. Please see photographs as they are part of the description. As with all my vintage items this monitor is sold as is.

It came from a well-maintained home in the suburbs where they very likely would not have held onto it if it was non-functioning. Indeed it was most likely put away as a functioning unit many years ago. Please see my 100% positive response from my many satisfied vintage electronics customers. It will be packed with suspension to maximize its safe delivery.

Thanks for looking.