Troubleshooting
2-23
Memory element tests
Tests 100.1, 101.1 and 102.1 check the memory elements (ROM, RAM and E
2
PROM) of
the Model 2001.
Test 100.1 – EPROM
Pass/Fail
Cannot properly read ROM.
All ROM bytes (except checksum bytes) are read, a checksum is calculated and com-
pared to the stored checksum. Failing this test indicates that one or more ROM loca-
tions cannot be read properly.
U611 and associated logic.
Test 101.1 – RAM
Pass/Fail
Cannot properly write to and/or read RAM.
This is an abbreviated version of power-on RAM testing. Memory locations are written
to, and then read back. It is highly unlikely that this built-in-test will fail. A unit with
faulty memory will probably fail the power-on memory test or will lock up intermit-
tently.
U609, U610 and associated logic.
Test 102.1 – RAM
Pass/Fail
Cannot properly read the E
2
PROM.
An attempt is made to read a byte of information from the 24C16 conÞguration
E
2
PROM (U617) and an acknowledgement signal is veriÞed. Failing this test indicates
a problem with the E
2
PROM or associated circuitry. This is a hardware test only and
does not verify the validity of conÞguration information stored in the E
2
PROM.
U617 and associated circuitry.
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