NASA promised to decide Sunday whether to delay the delivery mission.
No date for the spacewalk has been set yet; officials indicated it could occur sometime in the next week or so. The job is among those practiced by the astronauts before flight.
The SpaceX Dragon capsule holds more than 2 tons of station supplies and science experiments at Cape Canaveral. The shipment is already a month late for unrelated reasons.
If the Dragon soars Monday launch time is 4:58 p.m. EDT then it would reach the orbiting lab on Wednesday.
Flight controllers want to make sure enough redundancy exists at the space station before committing to the launch.
The bad computer, called an MDM or multiplexer-demultiplexer, is among more than a dozen located on the outside of the space station, used to route commands to various systems.
Officials said the failure has had no impact on the scientific and other work being conducted by the astronauts: three Russians, two Americans and one Japanese.
NASA is paying the California-based SpaceX Space Exploration Technologies Corp. as well as Orbital Sciences Corp. of Virginia to deliver space station goods. Russia, Europe and Japan also perform occasional shipments. The U.S. space shuttles carried up the bulk of station equipment until their retirement in 2011.