Four days before the final match day of the English Premier League (EPL) this year, 26,000 mioTV subscribers could not start up their set-top boxes due to a glitch. This was SingTel's third breakdown in two years.

For this, SingTel was slapped with a $220,000 fine by the Media Development Authority (MDA) - the largest penalty meted out by the statutory board. The disruption on May 15 lasted nine hours during which subscribers found themselves starring at a blank screen.

Investigations revealed that the breakdown was triggered by maintenance work that started the previous day, said the MDA in a statement Thursday evening. The routine maintenance, carried out by an unnamed contractor, involved replicating video-on-demand content to another server. But the operation failed as the hard disk of the receiving server was full. While attempting to recover the operation, the contractor keyed in a wrong command. This led to subscribers' set-top box bootup failure.

In the statement, MDA said that SingTel "has not exercised due care and diligence when carrying out routine maintenance activities during the incident". In determining the financial penalty, MDA considered factors such as service record, the extent and duration of the disruption, and the compensation offered to consumers. For instance, affected mio TV subscribers were offered a free one-month preview of all its channels or gift vouchers, or both.

"This is the third time in two years that (SingTel) has been found in breach of its Quality of Service licence conditions," the regulator said.

The conditions, which have not been spelt out, generally require pay-TV operators to ensure that their services are of "reasonable quality" that meet both the public and MDA's expectations.

SingTel had previously been fined $180,000 for a mioTV breakdown on May 13 last year, and $80,000 for similar outages in October and November 2011.