G05-802 Develops "Ring and Dot" at center after a few minutes.
I am putting together 2 Asteroids back to back. Both have a G05-802. Both re-caped, diodes cleaned, new deflection transistors. More or less, the works. Both have great displays. One, however, develops a slight dot in the center after a minute or two. Very faint. About 4 minutes in or so it becomes a ring, about 3/4 the size of a dime, with the original dot in the middle. It's pretty apparent its the beam crossing through the center. No amount of brightness or contrast adjustment prevents it from occurring. I thought it may be in the Z amp so I swapped in the the other deflection board. Same thing. Not sure if it could be anything in the HV can. I did look at the voltage at the anode cup. Solid on 12KV. It was getting late so I did not look at the other monitor yet or go much father in looking things over.
Anyone ran into this? Some Google searches earlier turned up other instances but no good leads. At least none I found.
I am putting together 2 Asteroids back to back. Both have a G05-802. Both re-caped, diodes cleaned, new deflection transistors. More or less, the works. Both have great displays. One, however, develops a slight dot in the center after a minute or two. Very faint. About 4 minutes in or so it becomes a ring, about 3/4 the size of a dime, with the original dot in the middle. It's pretty apparent its the beam crossing through the center. No amount of brightness or contrast adjustment prevents it from occurring. I thought it may be in the Z amp so I swapped in the the other deflection board. Same thing. Not sure if it could be anything in the HV can. I did look at the voltage at the anode cup. Solid on 12KV. It was getting late so I did not look at the other monitor yet or go much father in looking things over.
Anyone ran into this? Some Google searches earlier turned up other instances but no good leads. At least none I found.


