KB SV048

< Back

The first fault was no picture or sound. The PCF802 line
oscillator valve together with its cathode resistor RI49 and
the tuning capacitor in the cathode circuit CI27 (R149 had
gone low resistance and was burnt) were replaced, restoring
the picture and sound, and the oscillator coil was then
adjusted for a steady picture. The trouble now is line jitter.
The other tuning capacitor C126, the coupling capacitor to
the output stage (C129) and the sync separator transistor
have been replaced without success.
First look for a dry -joint on the printed board, then try
replacing the oscillator feedback capacitor C 125 and if
necessary the flywheel line sync discriminator diodes
D7/D8. If this does not clear the fault it is likely that one of
the polystyrene capacitors C115 -C119 inclusive in the
flywheel line sync discriminator circuit is defective. We
usually replace the lot in such cases. (ITT VC200 chassis.)

Table of Contents

Leave a comment

I have read the privacy policy and accept
Read our privacy policy

This form collects your name, email and content so that we can keep track of the comments placed on the website. For more info check our privacy policy where you will get more info on where, how and why we store your data.

This site uses Akismet to reduce spam. Learn how your comment data is processed.