Most of them involved incomplete channel number sequencing.
Supinya Klangnarong, a National Broadcasting and Telecommunications (NBTC) commissioner, said channel sequencing was not yet in line with what the NBTC had set.
"I tried watching using a digital TV set and a small 'high-tech' antennae and found the resolution and sound are sharp. All existing free TV channels can still be viewed," she said.
"ThaiPBS and MCOT, which come in high definition, are exceptionally sharp.
"I also tuned in to new channels such as Spring News, VoiceTV, True4U, Grammy, MCOT Kids & Family, Work Point and PPTV (HD)," she said.
Some cable viewers can start watching now, although the channel numbers are not standardised yet.
TrueVisions satellite-dish viewers can start watching on April 17, while PSI users can do so now.
"Technical problems need to be sorted out. Few people can watch now because most lack the equipment," Ms Supinya said.
She expected a full launch after the licences were issued on April 25.
Subsidy coupons valued at 690 baht which can be used to buy necessary reception equipment will be sent by mail to each household, starting with Bangkok, Nakhon Ratchasima, Chiang Mai, Songkhla, Ubon Ratchathani, Surat Thani, Rayong, Singburi, Sukhothai, Khon Kaen and Udon Thani.
All TV network operators must comply with the NBTC's "must-carry" rule, which requires them to relay the signals of 36 free TV channels starting Tuesday.
Under the analogue platform, Thailand has only six free-TV channels.
In any case, the existing six analogue TV channels will be broadcast simultaneously until 2020.
However, not all are happy with the NBTC's digital-TV plans.
They feel people are confused due to inadequate publicity.
"The NBTC should give more information before the launch. Many people tried to tune their TVs today, only to discover their networks or areas are not ready," said Suwit Mingmol, chairman of MCOT Plc's union.
"Some vendors take this opportunity to push their digital-TV products because they know people have little knowledge about them," he said.
"For example, people in Korat and Songkhla could not tune in because the networks are not ready and they need imported equipment which just arrived in Thailand today," he said.
"As well, the NBTC should be more open to opinions about content. With so many channels, it's hard to see how these channels will survive in the long run or how they can break even if at all," Mr Suwit said.How to go digital...
1. Satellite-dish and cable-TV users can watch digital TV starting Tuesday. All they need to do is pull the plugs and reconnect after a few seconds to let the systems reboot and resync. The new channels will be Channel 11-46.
Not all operators are ready. C-Band satellite users can start watching right away while KU-band viewers will be able to
watch from April 17. TrueVisions in both KU-band and cable systems would be ready this month or until further notice.
However, this method is for standard definition only. As of today, it is still unclear whether operators will agree to broadcast in HD for all 11 HD channels through satellite.
For HD reception now, viewers need to buy a DVB-T2 box with the NBTC or Doodee logos or use method 2 below.
2. Antennae users can buy a DVB-T2 set-top box and start watching right away using the antennae. The output can be TV, as well as PC monitors. The resolution is 1080i on LCD, LED and plasma screens and 576i on CRT screens.
They can also choose to wait for NBTC coupons for digital TV sets or DVB-T2 boxes at a discount or buy the boxes now with no discount.
Using this method, people in Bangkok, Nakon Ratchasima, Chiang Mai and Songkhla can start viewing on Tuesday. The network will gradually expand to other provinces.
3. Those considering buying new TV sets should choose those equipped with a digital tuner (iDTV) so they can plug in an antennae and start watching right away without the need to buy the DVB-T2 set-top box.
A DVB-T2 set-top box costs 900-3,000 baht, considerably more than the value of the NBTC coupon.
Check TV models with iDTV