"My television set is broken," a consumer complained in a series of carefully prepared telephone calls to Washington TV repair shops.

Describing identical symptoms, the caller got price quotes from 134 shops for replacing a component called a yoke in a Magnavox portable television.

The cheapest shop offered to do the routine repair job for $52.45 and the most expensive said it couldn't be done for less than $153.73. The average estimate was $103.94.

TV repair shops charging three times as much as others for the same job was one of the findings of the latest study of repair costs and practices made by the Washington Center for the Study of Services.

The privately financed consumer group confirmed what many consumers have long suspected - there's little if any correlation between the cost of repairs and the quality of the work.

And regardless of the price paid, roughly one consumer in four complained the work wasn't done right the first time. And from 13 to 29 percent of the customers said the work wasn't done when promised.

The Center for the Study of Services evaluated television, stereo and appliance repair shops by compiling questionnaires from about 10,000 consumers and by taking its own surveys of shops.

The results are published in the latest issue of Washington Consumer's Checkbook, a 96-page, $4.95 book that goes on sale today and is mailed to subscribers who pay $14 a year to become members of the center. Subscriptions and grants finance the non-profit group, which is headed by Robert Kurghoff.

The report rates 134 television repair shops, 25 hi-fi repair shops and 64 major appliance service centers in the District of Columbia, Maryland and Virginia, recommending the best shops in each category based on quality and price.

The quality recommendations are based on reports by at least 10 of the consumers surveyed; those rated by fewer customers are not included. Also taken into account were the equipment a shop has, the qualifications of its technicians and complaints to the Better Business Bureau.

Price recommendations are based on anonymous telephone requests for quotes on specific repairs, such as the Magnovox yoke replacement.

With any malfunctioning appliance or electronics item, the first rule is read the owner's manual, the consumer group recommends,estimating that one-third of service calls for TV repairs can be eliminated by following the book.

Just as important is getting a written estimate, a right guaranteed by law in the District of Columbia and Montgomery County. The report criticizes the practice by many shops of charging up to $30 for an estimate, saying such charges make it difficult for consumers to comparison shop.

The report also counsels against buying service contracts for repairs on any appliance. The average refrigerator requires $75 in repairs during its 15-year life, but service contracts cost from $23.95 to $45 a year, adding up to several times the likely repair bills.