|
well I decided to see what the TV would do on this set, I pulled the HOT, put on the variac, started out at about 20v for about 10min, very low current at the primary of the PT, cranked it up to about 60v, let is sit for about 20min, filter caps stone cold, all the filaments were starting to glow. went up to about 80v for another 20min, all looking good. Put the HOT back in with the cathode current monitor in place. go to full power, sound comes in, but zero cathode current and no hint of HV. Check the HOT (6je6) test very low on the tube tester, so I try another, this time HOT current quickly goes to 200ma and the CRT starts to get some raster, then all of a sudden it drops to about 50ma, no more HV. I notice the damper is glowing blue. Pull the damper and the shunt tube, the damper getter is gone the shunt tube looks like it has a lot of miles on it, so both of those get replaced, try again and get a nice nearly full raster (short on the bottom with some fold over). The vert out has one of those paper tube Electrolytics (prob the cathode bypass) on the circuit board, so I suspect that, could be the tube as well but I pressed on with the check out since I did not really want to pull the chassis. Lotsa green, so I check the green blanker tube, shorted, new one goes in, tint off, checked the phase detector, got a soft short in there, new one goes in,chroma lock not solid (horz rainbow) check the 6GH8 osc, hmm looks brand new, imagine that, anyway grab a pull and try it. finally it starting to look better. Color locks, tint control has plenty of range. Blue and Red are weak, Green is way strong, but the CRT tested with good tracking so I think there is something up, maybe the shorted blanker tube cooked a resistor in the green blanker circuit. did not check the burst amp or the demod tubes (the demod tubes were 6HZ6's I think). Before doing anymore I need to do a purity setup, the rings were rusted and the plastic mount was crumbling.
I dont want to get another project started, so I will prob just see if I can find a purity assy, try another vert tube and leave it at that for now. Get back to it when work calms down.
|