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Niechcial,Steve · 25th May 2021, 4:18 pm

Attached are some photos of my results so far. I spent a fun afternoon basically playing with different values of S-bend cap trying to get an acceptable balance between width, boost and EHT on both systems. A small change in S bend value makes a big difference- especially to width. As you can see, the results on 405 are almost perfect (although the EHT is a bit high). The results are not so good on 625, with some fold-over on the left and distinct stretch and compression on the picture.

I decided for the moment not to risk putting an extra winding on the LOPT to supply the flywheel line sync board. It would have to go around the main windings and that would bring it perilously near the overwind because the gap between the two would be small. Luckily the set was designed with a flywheel or straight sync option. The components are on a little board which unplugs. so I took out the flywheel board and substituted the two resistors and a cap which make up the direct sync linkage. The lock on 405 is pretty solid. On 625 a small adjustment makes a big difference to the foldover.

It all works well enough for me to try and mount the KB LOPT in the cabinet until the proper LOPT returns. Sadly not enough room in the original LOPT enclosure (which you can see in the photo) so will probably have to go top right above the PY/PL valve bases (these are mounted upside down)

25th May 2021, 4:18 pm	#35
Niechcial,Steve Hexode Join Date: Jan 2007 Location: Beckenham, London, UK. Posts: 373	Re: Murphy V659/759 restoration Attached are some photos of my results so far. I spent a fun afternoon basically playing with different values of S-bend cap trying to get an acceptable balance between width, boost and EHT on both systems. A small change in S bend value makes a big difference- especially to width. As you can see, the results on 405 are almost perfect (although the EHT is a bit high). The results are not so good on 625, with some fold-over on the left and distinct stretch and compression on the picture. I decided for the moment not to risk putting an extra winding on the LOPT to supply the flywheel line sync board. It would have to go around the main windings and that would bring it perilously near the overwind because the gap between the two would be small. Luckily the set was designed with a flywheel or straight sync option. The components are on a little board which unplugs. so I took out the flywheel board and substituted the two resistors and a cap which make up the direct sync linkage. The lock on 405 is pretty solid. On 625 a small adjustment makes a big difference to the foldover. It all works well enough for me to try and mount the KB LOPT in the cabinet until the proper LOPT returns. Sadly not enough room in the original LOPT enclosure (which you can see in the photo) so will probably have to go top right above the PY/PL valve bases (these are mounted upside down) Attached Thumbnails