While there were no riots in the streets, TV’s highly anticipated digital switchover was hardly a Y2K-style nonevent.

When D-day dawned on June 12, TV stations across the country shut down their analog transmissions and switched to all-digital broadcasts, and millions of households that still get TV over the air hooked up their converter boxes and scanned the airwaves for the new channels.

Most were rewarded with clearer pictures and a cornucopia of broadcasts they never knew existed. But at an undetermined number of those homes, the scans produced no channels at first. And when they finally did, in some cases channels were missing.

Many of those viewers took to the phones.

The FCC received 317,000 calls on the day of the transition, and the National Assn. of Broadcasters reported nearly 57,000 calls among the 350 stations it surveyed. “The most commonly asked questions had to do with converter-box rescanning and reception problems,” spokeswoman Shermaze Ingram says. Most of these were fixed when viewers rescanned their boxes.

More troublesome were scattered reports of channels possibly missing due to insufficient signal power. Most of those were in the VHF band (channels 2 through 13), affecting stations that had been broadcasting their pre-switchover digital signal on UHF and then reverted to VHF channels after the transition. There are now 428 digital VHF stations, according to FCC spokesman Mark Wigfield.

“Such stations experienced problems in about 10 to 15 markets,” Wigfield says. In Washington, D.C., for example, the over-the-air signals of ABC affiliate WJLA and CBS affiliate WUSA were unavailable in some homes, even after rescans.

Similar issues surfaced at stations in Chicago, Philadelphia, New York and elsewhere. The FCC sent field teams to several cities to investigate the problems, Wigfield says.

Meanwhile, WHDH, the NBC affiliate in Boston, which lost some of its over-the-air viewers after the switch, went back to simulcasting its digital signal on two separate channels, and advised affected viewers to have their converter boxes scan again.

“The station’s signal problem is a result of a power-allocation issue,” WHDH told its customers. “The power level assigned to WHDH for its post-switch to channel 7 is not sufficient to maintain the signal strength that WHDH had prior to the transition.”

Wigfield acknowledges that insufficient station power is a thornier issue than consumer antenna problems. Because of potential interference with other broadcasters, “there’s no automatic way a station can increase its power level,” he says.

While initial reports of lost stations came from the East and Midwest, some viewers in the Los Angeles area also reported losing channels. “Our signal is good, but we know people are having some problems with their antennas and with rescanning,” says Therese Gamba, programming veep at L.A.’s ABC-owned KABC.

“It remains to be seen whether a significant amount of people are having difficulty receiving our channel,” adds KABC engineering VP John Holland. People who “bought antennas skewed for UHF channels” may be at a disadvantage.

“The whole world knew there would be dropoffs,” says a spokesman for Hearst Television. “The key is how quickly this is dealt with.”

At least one station that was able to boost its power output as part of the conversion fared better than some others that didn’t have that option. “Ninety percent of the calls we received focused on rescanning and antenna issues,” says Dave Muscari, product development veep at Dallas-Ft. Worth ABC affiliate WFAA. “You could count on one hand the few truly angry people out there.”

Overall, the decision to delay the digital transition from February to June proved to be a smart one. Nielsen says the percentage of U.S. households that were completely unready for the switch last week (2.2%) was half of that in mid-February (4.4%), though the percentages remain relatively high in homes headed by African-Americans or Hispanics.

And any headaches stations are dealing with now — with the broadcast season and NBA playoffs in the rear-view mirror — are nothing compared with those that could have been expected at a time of heavier television viewing and events, including the Academy Awards.