Councilman Samuel B. Wright, one of the city's most powerful black politicians, was found guilty of conspiracy and extortion.

Wright was tried in U.S. District Court in Brooklyn on charges stemming from a $5,000 kickback he allegedly sought and received in 1973 from a California firm. No sentencing date was set.

The government charged that Wright, in return for the kickback, promised to increase his school district's purchase of educational materials from the company by $400,000.

The firm Behavorial Research Laboratories, of Palo Alto, sold educational materials to School District 23 at the time Wright chaired the local board.

The government said Wright made the promise while in San Francisco in 1973 attending a convention sponsored by Behavorial Research.

U.S. Attorney Peter Schalm said Wright called James Phipps, New York sales manager for the Palo Alto firm, and asked for the $5.00. As a result, Schalm said, a $500 check for a speech Wright gave at the convention was changed to a $5,500 check.

Wright's attorney, Gustave Newman, had contended that the $5,500 check to his client was for the speech and was reported on Wright's income-tax return.