Tidings of comfort and joy: The Ford's Theatre production of "A Christmas Carol" has been turned into a slightly chunky but quite enjoyable television show. It will be shown on Channel 26, the producing PBS station, tonight at 9 and again Monday afternoon at 2.

Since the tape was assembled from live-audience performances at Ford's, there are no zippy electronic gimmicks sparkling up Dickens' classic Christmas ghost story. But the stage effects photograph surprisingly well, and they include giant visiting apparations devised by puppeteer Ingrid Crepeau.

Rae Allen and Timothy Near adapted the oft-adapted work for the stage, and versatile TV director Kirk Browning did the best he could at capturing it for television. Browning proves himself shrewd and alert, but unable to offset the clamor of actors who are over-projecting their heads off for the benefit of the theater audience, and to the certain annoyance of the home audience.

And yet there is something so robust, so bona fide and so extravagant about Ron Bishop's performance as Scrooge that even this obstacle is surmounted. Bishop is also the stage director of the production, which includes a few traditional holiday songs and such devices as having the chorus chant out some of the exposition.

Bishop's Scrooge seems somehow evocative of John Belushi as an old man -- with the same kind of self-mocking bluster Belushi uses for his more hysterical roles -- and, in long-shot, Bishop's playful portliness, not the usual Scroogian physique, brings to mind the late Zero Mostel. That can't hurt.

Bob Cratchit has always been pretty insufferable, and he is especially so in this version, which also boasts the yechiest Tiny Tim in memory. Perhaps it's a drawback that Scrooge is thus a hero from the start, but then, it always has been his story.

Two movie versions of "A Christmas Carol" will also be available to area viewers during the holiday period ahead. Channel 20 will air the superior 1951 British version, with Alastair Sim, tonight at 6, and Channel 5 will present the satisfactory 1938 MGM version Sunday morning at 10:30.

Channel 5 also plans to show another holiday perennial, "Miracle on 34th Street," with Edmund Gwenn and a very young Natalie Wood, no fewer than three times this weekend: at 11:30 tonight, at 3 p.m. Sunday, and at 8 p.m. Monday. The station will also show Frank Capra's heartwarming masterpiece of naive art, "It's a Wonderful Life," Sunday at noon.

Other scheduled seasonal films include the 1942 "Holiday Inn," in which Bing Crosby introduced "White Christmas," Sunday at 5 p.m. on Channel 20, and the Paramount Musical "White Christmas," divided into two parts, Monday and Tuesday at 4 p.m. on Channel 7.

Channel 20 had planned to show Danny Kaye in "Hans Christian Anderson" in a 90-minute timeslot Christmas Day at 9:30 p.m. This seemed rather severe for a film that ran 120 minutes in original release. Prevailed upon in the name of humanity, the station management yesterday extended the time period to two hours.