Well here is number 2. A 12 inch Zenith Porthole as you can well see. When I got her the 12up4 had an open filiment. Took a while to find a good crt, but I got a real good one and she shows real bright.
Full recap a few marginal tubes replaced and a lot of TLC to refinish the cabinette with many coats of clear lacquer. Stripped the solid brass control door and re-polished it, then re-lacquered it. Same done to the brass trim rings aorund the On/Off/volume and chanel knobs. Took the Die cast picture tube safety glass frame and cleaned it real good and gave it a couple coats of lacquer so it looks like new.
Runs real nice and gets a nice picture except for a horizontal linearity problem that has me stumped. As per John Marinello's suggestion I may try to fiddle with some capacitor values in between the Horizontal discharge tube and the grid of the horizontal output to see if I can get the trace to be more linear. Right now the picture is streched on the left and compressed tightly on the right.
Question... does the scan start on the left and end on the right or vise versa?
Also have another question. The filiment winding that feeds the 1B3 which wraps around the core of the flyback, dosent do a complete loop all the way around the flyback core. It just does a 180 sort of like a u-turn. Is this the way it is supposed to be? I have always seen 1 complete turn, a full 360 around the flyback core on all the sets I am familiar with. Can someone who has a set like this verify if the winding is to be a horse shoe sort of 'U' turn or is it supposed to be 1 full complete 360 loop around the flyback core?
So here are the photos... Enjoy!
