When polytechnic student Ang Bing Xuan, 18, and his family returned home after dinner two Sundays ago, they were not expecting the lift ride up to their flat to be "like a roller coaster".
The lift went up and down a few times before finally stopping at the 14th floor.
"The lift would suddenly stop and then jerk downwards, and then go up again," he said of the incident on May 6 at Block 670 Jalan Damai.
When The Straits Times visited the block yesterday, representatives from the Building and Construction Authority (BCA), the Housing Board, Aljunied-Hougang Town Council (AHTC) and lift maintenance contractor G9 Elevator were present to inspect the lift.
The incident was first reported by Lianhe Wanbao on Sunday.
Residents told ST that both lifts at the HDB block have been intermittently faulty for several years. The problems also included the lift door being unable to close fully.
The lifts are managed and maintained by AHTC. They were built by Express Lift, which is no longer registered in Singapore.
AHTC said it responded to a report of a faulty lift on May 6. The lift was shut down to run tests and became operational again on May 8.
Mr Ang's experience on May 6 was not the residents' first encounter with the faulty lift.
Earlier that day, his mother was in the lift when it travelled up and down a few times without opening its doors. She got out when the door finally opened on the ground floor and reported the incident to the town council.
The lift was then under repair for a few hours that day. The Ang family had assumed the fault was rectified when they saw the lift back in operation in the evening.
A day before, another family had a similar experience.
A logistics analyst who wanted to be known only as Ms Goh, 45, said her husband, four-year-old son and 75-year-old father-in-law were in the lift when it stopped suddenly on the third floor. It then "descended quickly to the ground floor".
They, too, reported it to the town council.
Another resident, Ms Nur Farahnishyah Khalid, 22, a processing officer, said she had several experiences of being in the lift when it would "suddenly stop and then plunge" .
AHTC said it is working with the BCA to avoid a recurrence of the problem. The BCA said it is investigating the matter.