28-04-2018, 04:18 PM
Thanks Terry, I guess these were 110 degree sets. I can well imagine different electron beam path lengths in these sets and varying the focus to take account of that might give some improvement.
With the Emiscope 6/6 I think the radiused screen probably doesn't cause much path length variation over the scan and whilst my focus control does give a reasonable range of focus adjustment in the screen central area the point of best central focus is also the point of best edge focus and any move away from that point only worsens the edge focus.
![[Image: Old&New1%20(Medium).jpg]](http://www.nostalgiatech.co.uk/Old&New1%20(Medium).jpg)
My scan coils were down from the start of the cone by about 4 or 5mm due to me removing the push-about coil but with this coil in place and the scan coils fully up to the cone I get no improvement in edge focus. If I had to pass a judgement I would say the edge focus is very marginally worse with the scan coils hard against the cone.
Peter
With the Emiscope 6/6 I think the radiused screen probably doesn't cause much path length variation over the scan and whilst my focus control does give a reasonable range of focus adjustment in the screen central area the point of best central focus is also the point of best edge focus and any move away from that point only worsens the edge focus.
My scan coils were down from the start of the cone by about 4 or 5mm due to me removing the push-about coil but with this coil in place and the scan coils fully up to the cone I get no improvement in edge focus. If I had to pass a judgement I would say the edge focus is very marginally worse with the scan coils hard against the cone.
Peter
