Use digital TV set-top box with due caution to ensure safety -CHOICE # 380

In collaboration with the Electrical and Mechanical Services Department (EMSD), the Consumer Council has released a test report on the safety of this new addition of household electrical appliance.

This followed public concern that some of the models available in the market were allegedly found to hot up considerably whilst in use.

The test was conducted on 10 samples in accordance with the IEC60065 standard. All were shown to comply with the IEC standard on temperature rise. 6 models were rated to achieve full score in overall safety on a 5-point rating.

4 samples, however, were found to be less than perfect: 3 samples scored 4.5 points while 1 sample received 3.5 points.

The safety rating was based on: construction (40%), protection against electric shock (25%), resistance to heat (20%), temperature rise (10%) and marking and instructions (5%).

The principal safety deficiencies detected in the 4 models included:

• The insulated internal wire could come to be in contact with the accessible metal enclosure. In the event of insulation failure, it may pose risk of current leakage.
• Inappropriate fixing of the PCB (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 to separate the primary and secondary windings of the switching transformer.
• The creepage distances between live and neutral printed circuits in the PCB is slightly less than the safety requirements.

The EMSD has requested the manufacturers concerned to rectify such deficiencies. The manufacturers have responded positively to improve their products.

Nonetheless, consumers are advised to be cautious in using set-top boxes for digital TV reception - whether or not the product could totally pass the safety test. Important cautions to heed include:

• Place the set-top box in a well-ventilated area clear of such household items as flower vase that could accidentally spill water into the device.
• It is normal that set-top box when in operation will generate heat and rise in temperature. But should the external casing become scalding hot to touch or other abnormal conditions arise such as smoke emission and burning smell, stop the use immediately and cut off the electricity supply.
• Do not clean with a wet cloth; use a dry cloth or a mini vacuum cleaner to remove dust.
• If the set-top box is not expected to be in use for a long time, do not put it on standby mode, cut off the electricity supply completely.

In the first 5 months of this year, the Consumer Council has received some 36 cases of complaints over set-top boxes.

Some were related to door-to-door illicit sale activities by salesmen claiming to be staff of the Housing Department. The salesmen were allegedly spreading the rumour that the existing four free analogue TV channels would soon be terminated and that new set-top boxes would need to be installed for free television reception.

There is no truth in such allegations. While the Government has set 2012 as a target to switch off the existing analogue TV service, it is a tentative target. The Government will take into account the actual market conditions and give sufficient prior notice to the public before deciding on the exact timing. The existing analogue service will continue to be provided until the formal announcement by Government.