kcs 47a doorknob cap
 

recapped this thing last year. just now getting back to it.
fired the set up and it had a dim out of focus picture. was only getting 8,000 volts to anode. removed the doorknob cap. it was hot. now a i have a bright picture. do i need to replace this or just leave it out. i also have no audio any pointers on this chassis.
thanks steve

Steve,

You won't hurt anything but possibly picture quality by leaving that doorknob cap out of the HV circuit. I'd replace it if it was my set. I gather you have a metal shell CRT? I have some sets with that chassis but little experience on the bench with them yet. Can't help with the audio question.

Rob

Doorknob cap
 

In all-glass CRTs, the internal 2nd anode coating in combination with the grounded external aquadag coating form a high voltage cap to ground, about 500 pF. This filters the rectified output of the 1B3 (half-wave DC pulses at 15,734 KHz) to steady DC.

In a metal shell CRT, there is no "capacitor", so a 500 pF doorknob was added externally to perform the filtering function. Leaving it out is similar to leaving out an electrolytic in the B+ supply, although the "hum" produced will be at H frequency and will affect only the CRT.