The Consumer Council has found safety deficiencies in four out of 10 digital television set-top box samples. The test rated the models' construction, electric shock protection, heat resistance, markings and instructions.

The major safety defects included:

* insulated internal wiring could come in contact with the metal enclosure, posing a shock risk;

* improper fixing of the circuit board by the earthing terminal screw;

* the internal component could be touched if replaced by a longer screw;

* only one layer of insulating tape separated the primary and secondary windings of the switching transformer; and,

* the creepage distances between live- and neutral-printed circuits in the circuit board was less than safety requirements.

The Electrical & Mechanical Services Department has ordered the manufacturers to improve the products.

Meanwhile, the council has received 36 complaints over set-top boxes so far this year. Some were about illicit door-to-door activities by salesmen claiming to be Housing Department staff. They reportedly said the four free analogue television channels will soon be terminated and new set-top boxes would be needed for free television reception.

While the Government has set 2012 as a tentative target to switch off analogue TV services, it will consider market conditions and give sufficient public notice before deciding on the exact timing.