HP 3457A Service Manual page 210

Table 8-3. Self Test Failure Information
TEST# AUXERR# FAILURE DESCRIPTION
N/A 1 Isolation error in normal operation (not during self test)
1 2 A/D controller self test error
2 4 Isolation self test error
3 8 Integrator convergence error
4 16 Front end zero offset error
5 32 Current source, gain select or input divider error
6 64 Amps function error
7 128 AC amplifier 0C offset error
8 256 AC attenuator flatness error
9 512 Ohms precharge circuit error
0) 1026 U602 ROM checksum error
0 16384 | Nonvolatile RAM (U603) or RAM protection circuit error
8-80. Updated Self Tests 0, 1, and 2 (1ESI)
In addition to the 3 Power-on Self Tests, 7 other self tests may be executed by using the TEST com-
mand. All self tests are executed sequentially when the TEST command is executed and cannot be ex-
ecuted individually; however, the self tests are separated and numbered below to aid in troubleshooting.
Test 0 checks much of the circuitry on the Main Controller assembly All, There are 2 subtests in-
cluded in Test 0 and they are executed in the following sequence: 1) U602 ROM Checksum, 2)
Nonvolatile RAM (U603) and RAM write protection circuitry test. These are also checked as part of
the power-on test.
The ROM checksum tests against hard coded results. If the checksum of U602 is incorrect, executing
the AUXERR? command will return a value of 1024. During the nonvolatile RAM test, FF, 55, 00 is
written to each non-CALRAM location and read back (data presently in RAM is preserved). If the
RAM test fails, the AUXERR? command would return 16384. The last part of test 0 writes to the
CALRAM portion of the nonvolatile RAM and reads back. If the information written is read back,
this indicates the RAM is not protected. In this case the AUXERR? command would return the value
16384.
HP 3457A Multimeter
8-45