Asteroids help

[keptboy]

Asteroids upright cabinet plays but is not blankiing off the lines from the asteroids so it draws extra lines on the screen - not sure what is causing this is anyone can advise please

Here is a link

https://youtu.be/D8phdoANd5wkeptboy2021-02-06 16:39:07

 

[Equites]

Your brightness is way too high.

The pot wheel is on the deflection board on the monitor, tweak it till the centre bright dot is gone. Be quick, it will burn the phospor off your tube.

 

[keptboy]

How has it happened as it was working fine the day before

 

[Equites]

Old pots are known to drift.