PYE 713 CHASSIS

The trouble with this set is noise, i.e. a grainy picture. The
picture itself is good, and all the controls work correctly.
The aerial has been checked and seems to be in order. Any
ideas as to the cause of the trouble?
The fault on this and similar chassis, e.g. the 731, seems
to be fairly common. The usual cause is a dry -joint
somewhere in the selectivity/gain module – the largest can on
the i.f. panel. The trouble can be due to the griplets used to
connect the sides of the copper together, or to the group of
small ceramic capacitors in the middle of the unit. Raise and
resolder the capacitors, so that the coating is clear of the
joints.