by NASA

“ On December 31, a check of the satellite revealed that it was functioning satisfactorily except for a small power drain by voltage regulator No.1.
Because of difficulties experienced with the command system of transponder No.1, project managers decided to employ the other transponder. On January 3, 1963, they activated transponder No.2 and carried out a continuing sequence of transatlantic television, telephone, and teletype communication tests. Some difficulty has been encountered with the command system of the satellite. ”

“ The satellite's voltage was indicated at 22.5, which is below the lower limit of 24 volts required for operation of the communications equipment with- damage to the battery.
The trouble was traced to the voltage regulator in the No. 1 transponder -- the receiving, amplifying, and transmitting apparatus in Relay. Relay is equipped with two identical transponders, each with its own voltage regulator. The voltage regulator channels power to the transponder at a proper voltage and acts as an on-off switch for the transponder. ”

“ Reception in Europe was excellent. The television pictures from the gallery were transmitted conventionally to the Relay ground station at Andover, Maine, from which they were beamed to the satellite for retransmittal to Europe. ”