2-4
Diagnostics
Description of Tests
Description of Tests
SDRAM Refresh
This test veri
fi
es the write/read functionality and accuracy of the SDRAM chip (U3) attached to
the microprocessor, SH7705 (U1).
A failure of this test indicates a problem with the SDRAM chip or associated circuitry on the
Engine Board.
Flash Memory
This test veri
fi
es the manufacturer ID and the size of the NAND Flash installed. The test then
writes and reads back one or more blocks not occupied by the
fi
le system. This test also indicates
if the NAND Flash is formatted or unformatted.
A failure of this test may indicate a problem with the with the microprocessor (U1), NAND
Flash (U2), Fin CPLD (U45), or related circuitry on the Engine Board.
MARA Validity Check
Note
: Throughout this manual many references are made to the MARA 1 and MARA 2 ICs. For
service personnel unfamiliar with the PC3x, MARA is the name given to the two Kurzweil
Custom Sound ICs.
This tests veri
fi
es the proper content of certain read-only registers and the read/write accuracy
of certain read/write registers on both MARAs. It also writes and reads back the various register
blocks in both MARAs that are implemented as RAM cells.
A failure of this test may indicate a problem with the with the microprocessor (U1), MARA 1
(U11) or MARA 2 (U10), or related circuitry on the Engine Board.
MARA Communications
This test transfers data from one MARA to the other via the SMOOCH interface and checks the
accuracy of the data received. All four SMOOCH inputs and outputs are exercised.
This test will likely fail if the MARA Validity Test fails. However if the MARA Validity Test
passes and this test fails, it may indicate a bad solder joint underneath one or both MARAs.
