Someone has posted a schematic and article for eliminating retrace lines in the Gallery section of Antiqueradios.com
It looks very simple consisting of only a resistor and a capacitor.
http://168.103.222.44/cgi-bin/forums...assCookie=true
Click on the Gallery link at the top of the page or use this link to go directly to the Gallery:
http://antiqueradios.com/photogallery/
Eric