Sec.  15.32   Test procedures for CPU boards and computer power supplies.

   Power supplies and CPU boards used with personal computers and for which
   separate authorizations are required to be obtained shall be tested as
   follows:

   (a) CPU boards shall be tested as follows:

   (1) Testing for radiated emissions shall be performed with the CPU board
   installed in a typical enclosure but with the enclosure's cover removed so
   that the internal circuitry is exposed at the top and on at least two sides.
   Additional components, including a power supply, peripheral devices, and
   subassemblies, shall be added, as needed, to result in a complete personal
   computer system. If the oscillator and the microprocessor circuits are
   contained on separate circuit boards, both boards, typical of the
   combination that would normally be employed, must be used in the test.
   Testing shall be in accordance with the procedures specified in  Sec. 15.31.

   (i) Under these test conditions, the system under test shall not exceed the
   radiated emission limits specified in  Sec. 15.109 by more than 6 dB. Emissions
   greater than 6 dB that can be identified and documented to originate from a
   component(s) other than the CPU board being tested, may be dismissed.

   (ii) Unless the test in paragraph (a)(1)(i) of this section demonstrates
   compliance with the limits in  Sec. 15.109, a second test shall be performed
   using the same configuration described above but with the cover installed on
   the enclosure. Testing shall be in accordance with the procedures specified
   in  Sec. 15.31. Under these test conditions, the system under test shall not
   exceed the radiated emission limits specified in  Sec. 15.109.

   (2) In lieu of the procedure in (a)(1) of this section, CPU boards may be
   tested to demonstrate compliance with the limits in  Sec. 15.109 using a
   specified enclosure with the cover installed. Testing for radiated emissions
   shall be performed with the CPU board installed in a typical system
   configuration. Additional components, including a power supply, peripheral
   devices, and subassemblies, shall be added, as needed, to result in a
   complete personal computer system. If the oscillator and the microprocessor
   circuits are contained on separate circuit boards, both boards, typical of
   the combination that would normally be employed, must be used in the test.
   Testing shall be in accordance with the procedures specified in  Sec. 15.31.
   Under this procedure, CPU boards that comply with the limits in  Sec. 15.109 must
   be marketed together with the specific enclosure used for the test.

   (3) The test demonstrating compliance with the AC power line conducted
   limits specified in  Sec. 15.107 shall be performed in accordance with the
   procedures specified in  Sec. 15.31 using an enclosure, peripherals, power supply
   and subassemblies that are typical of the type with which the CPU board
   under test would normally be employed.

   (b) The power supply shall be tested installed in an enclosure that is
   typical of the type within which it would normally be installed. Additional
   components, including peripheral devices, a CPU board, and subassemblies,
   shall be added, as needed, to result in a complete personal computer system.
   Testing shall be in accordance with the procedures specified in  Sec. 15.31 and
   must demonstrate compliance with all of the standards contained in this
   part.

   [ 61 FR 31048 , June 19, 1996, as amended at  62 FR 41881 , Aug. 4, 1997]