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View Full Version : Bright dot when turning off northstar advantage



kyeakel
October 26th, 2013, 12:41 PM
I bought one of the northstar advantages from Andrew Lynch, thanks Andrew. After adding 2 diskette drives, and redoing the keyboard with all new foam pads, I can run the demo/diagnostics diskette. Everything seems fine, except when I turn off the machine the raster stops scanning and there is a very bright dot in the center of the screen. This dot slowly fades away, but I'm concerned that it is there at all. Should there be a bleed off resistor or circuit to prevent this from happening?

Kipp

Chuck(G)
October 26th, 2013, 01:57 PM
This was the behavior of a lot of old B&W TVs as well. I don't think that the bean stays on long enough to matter (i.e. to burn the phosphor).

kyeakel
October 26th, 2013, 06:54 PM
This was the behavior of a lot of old B&W TVs as well. I don't think that the bean stays on long enough to matter (i.e. to burn the phosphor).

Thanks Chuck. Just wanted to have some reassurance that this was ok.

NF6X
November 24th, 2013, 10:06 PM
This brings back old memories of our black and white vacuum tube TV when I was a little kid!

kyeakel
November 25th, 2013, 05:18 AM
Interesting enough, I now have two of these machines and they exhibit different behaviors when being turned off. One does the white dot as previously mentioned, and the other does a quick vertical line top to bottom and then nothing.

Kipp