My First Predicta

[Chris K]

Originally Posted by Yamamaya42

I'm not sure which Predicta you have, nor have I had a chance to work on one yet, but they should be mostly alike, found this, so.

http://www.earlytelevision.org/pdf/p...sams_439-1.pdf

Obviously the missing voltages are the first task.
No 140v = no IF, thus no video/ sound.
No 260v C will kill the horizontal oscillator/ HV, and thus you have no boost and it will be at low of 200v ish.

Looking at THIS schematic anyway, there has to be something really weird wrong for 260v C to be missing, without that, the cathode of the audio output will be all wrong, and thus 140v will be wrong as well.

That's the Sams I'm working from. I see what you're saying about Source C and the 140v. I'm not all that great with schematic symbols...is there anything significant to that X on the line between 260 B and 260 C line right next to the .047 capacitor designation? Could resistor R75, the 18K 2 watt be an issue? I'm going to replace the rectifier diodes anyway but I have 250 v DC coming out of them and not the 280-290 V that should be there.