View Full Version : 1948 motorola table top


timmy
07-25-2015, 10:17 AM
ok so i have this 48 motorola, its been recapped fully even the caps in the verticle since i had major problems with the verticle. now i have this problem with the brightness up max im getting lines on the top of the picture and it pulls down alittle, the lines are left to right and are about 2-3 but if i lower the bright it goes away. the schematic shows a 1 meg resistor in the bright circuit but what looked like factory was a 2.5 meg and the later sets used a .470k. if i put a 1 meg in there the problem is worse and even worse if i try a 470k so the higher the value of the resistor the darker the screen is. i would like to put the right resistor, the 1 meg in but find out why this is happening with the lines. for some reason with the bright up it seems like its taking something for somewhere else and then it effects the verticle by pulling it down a bit and getting these lines. i posted a pic of these lines not long ago on a scope tube i was using and thinking the verticle was doing this but after recapping everything went away except for the lines. i could just leave the bright down alittle but i would like to find the problem and make it right. the correct resistor for this chassis is a 1 meg and its a ts4d chassis.