G.E.C. BT1743

< Back

For the first thirty minutes after switching on the picture on this set fills the screen correctly. After this period of time however, a dark margin, about 1″. wide, develops down each side of the
picture. I have checked the frame output valve by substitution but without improving the situation. -H. V. Powell (Lydbrook, Gloucestershire).
Since the width of the picture decreases, the
trouble lies either in the line or h.t. circuits, and
not in- the frame section. First check the line
time -base valves for emission, including the
booster diode, and replace if less than 75%
good.
If the valves are in order, check the h.t. rectifier and replace if the d.c. output voltage is less
than a.c. input voltage.

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.