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 Post subject: Re: XY Scope Project
PostPosted: Jun Sun 03, 2018 4:12 pm 
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Location: Baton Rouge, Louisiana
The mu metal worked fairly well.
Around the neck and body did not help.
The transformers (mounted behind the crt) being shielded helped significantly.
The shielding job isn't especially pretty, so I will work on that a bit more.
So it seems to be time to begin work on the deflection amps.
The photos were taken while manipulating the horizontal position and vertical position fairly slowly.
Moving the spot fast shows much less discrepancy.
It is an exercise in dexterity to move the spot and take a photograph at the same time!
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horizontal.jpg [ 19.52 KiB | Viewed 239 times ]
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vertical.jpg
vertical.jpg [ 8.91 KiB | Viewed 239 times ]

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 Post subject: Re: XY Scope Project
PostPosted: Jun Mon 04, 2018 11:38 am 
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Location: Warner Robins, GA
Looks almost like there might be ripple voltage on the B- supply.

Try putting another cap across the last filter cap in the B- supply and see if the spot is better when moving it around.


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 Post subject: Re: XY Scope Project
PostPosted: Jun Fri 08, 2018 6:58 pm 
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Tube Radio wrote:
Looks almost like there might be ripple voltage on the B- supply.

Try putting another cap across the last filter cap in the B- supply and see if the spot is better when moving it around.

Okay, I tried that. No change.
I am going to roll with it and see what happens.
The plan for the deflection amps has pretty well gelled in my head, so onward I will forge.
Also, toward the right extreme and the bottom extreme, to a lesser extent, the focus gets worse.
There are individual small issues to be worked through; hopefully they don't add up to a monstrous case of discouragement.

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 Post subject: Re: XY Scope Project
PostPosted: Jun Fri 08, 2018 7:00 pm 
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Location: Warner Robins, GA
The focus issue there could just be because of it just being a spot as the astigmatism voltage has to be close to the potential of all deflection plates so the two plates being higher than the other two might be affecting focus somewhat.

Is it possible to post a schematic of the circuit as it is at this point?

Might help figure out the issue.


Last edited by Tube Radio on Jun Fri 08, 2018 7:12 pm, edited 1 time in total.

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 Post subject: Re: XY Scope Project
PostPosted: Jun Fri 08, 2018 7:04 pm 
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Location: Baton Rouge, Louisiana
Tube Radio wrote:
The focus issue there could just be because of it just being a spot as the astigmatism voltage has to be close to the potential of all deflection plates so the two plates being higher than the other two might be affecting focus somewhat.

Yes, I understand what you are saying.
The problems so far may well not be noticeable when the tube is run "at speed".

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