Kurzweil K2000 Service Manual page 80

SECTION
4
DIAGS1_0.DOC 12/13/92
from each address and compares it to a checksum stored in the ROM chips. It
also checks for errors in the pin connections of each of these chips. If all
checksums match, the test is a success. If there are checksums that do not
match, the display will show either "Even Fail N or "Odd Fail.N If an Even Fail
message appears, remove the chip located at U3 and test it in an EPROM
programmer. If the checksums match, the chip is good, and a connection
problem at U3 is indicated. If the checksums do not match the chip is
improperly programmed and should be reprogrammed or replaced. Likewise, if
an Odd Fail message appears, remove and test the chip from location U6.
NOTE:
The sockets at U3 and U6 are labeled "SETUP N on the engine board.
Even so, the chips installed in these sockets are the Engine software EPROMs.
This discrepancy is due to a design change that was made after the engine
board was finalized and printed. For Engine software Version 1.1 and 1.2,
the SETUP sockets contain the Engine software, and locations U2 and US are
unused. Nevertheless, the Boot EPROM test checks the Engine software EPROMs.
4.21.3 Setup EPROM Teat
Similar to the Boot EPROM test, this is intended to check the data and pin
connections of the ROM chips located at U2 and US on the engine board. For
Engine software Version 1.1 and 1.2, these locations are unused, and the test
will fail. This does not indicate a malfunction.
4.21. 4 PSRAM Teat
This is a memory test of the pseudo-static RAM chips located at U7 and US on
the engine board. The results will be either Success, Data Failure, or
Address Failure. If this test fails, the RAM chips should be replaced. If
unit has the P/RAM option, the test will take approximately 45 seconds to run.
Without the P/RAM extension, the test takes approximately 11 seconds.
NOTE: This test checks only to ascertain whether the pseudo-static RAM chips
at U7 and US are good. It does not check to determine if the memory in the
P/RAM option (if installed) is good. To check whether the extra RAM is
recognized by the unit, it is necessary to enter Song mode or Disk mode when
finished with the diagnostics. The top line of the display will indicate the
amount of available RAM. This number should be approximately 120K if there
is no P/RAM extension, and approximately 760K with the P/RAM extension. If
the unit has the P/RAM option board (at connector J1), the display should show
the additional RAM space. If the display does not indicate approximately
760K of available RAM, the P/RAM option board may be defective, and should be
repaired or replaced.
4.21.5
I/O Port Teat
In this test, the integrity of data transfer within the CPU (location U9) is
tested. This is done by writing a test data pattern from the low bit
addresses of the CPU to the high bit addresses. The high bits then read the
pattern and compare it to the original. If the patterns match, the test is a
success. If the test fails, the CPU may be bad, but it is more likely that
there is a problem with the I/O bus.
4.21.6 Interrupt Teat
Also an I/O test, the Interrupt Test checks the connection between the IRQO
(interrupt request) pin and the floppy disk controller in the CPU. A
successful Interrupt test indicates that interrupt requests from the floppy
34