How Can We Help?
The trouble with this set is a rope-like striation down the
right-hand side of the screen, about two inches from the
edge. It’s more visible on dark scenes. The EW modulator
module has been checked and seems to be o.k., also the
aerial. We live in a good reception area.
This “pearl-string” efect can be due to several things on
these Grundig chassis. First ensure that all the ferrite beads
in the line output stage wiring are present and correct — one
at the cathode of the flyback diode Di511, and another at
the cathode of the scan thyristor Ty518. If necessary, check
diode Di514 on the e.h.t. control module by substitution.
Then try the efect of bridging the connecting points across
L501 in the drive circuit to the flyback thyristor’s cathode
gate. This inductor must be left in circuit, but may need to