6-74
Failure of one of the Front-Panel JLPtests may be indicated only by flashing out the failed test number
on the Trigger LEDs, but if the diagnostic testing can continue past the failure, the Extended Diagnos-
tic menu will be seen with the FPP test marked FAIL. The usual result of a Front Panel JLPfailure is a
locked up front panel (the button and pots will not be functional). To rerun the diagnostic testing from
the front panel to check the Trigger LEDs for the failed test number, it is necessary to turn off then
turn back on the 2430.
Troubleshooting Procedure:
4600 U742 and U751. Four bit patterns are written to the FPP and echoed back. If these are not
returned properly, the test result
=
FAIL.
4500 U861 pin 6 (FPDNRD)should clock pin 6 LO.
4400 U700 (Front PanellLP) checks its internal RAM, ROM, Timer, and A/D. Any failure will set the
test result to FAIL.
4300 U861 pin 9 (WR TO HOST) should clock pin 9 HI.
4200 U861 pin 6 should be reset to its HI state via U862C and U862D.
4100 U861 pin 9 should be reset to its LO state via U8628 and U862A.
Test Steps:
The Front Panel ILP internal diagnostics require that the ILPbe reset. Therefore, the structure of the
FPP tests is such that the processor is initialized when completed. This requires that ALL of the tests
be run in order. Therefore, all tests will be run even though it appears that only a sub-test is being
executed.
The Front Panel Processor test first sets all test results to NULL. Any failure to complete all the tests
will result in a locked front panel. Depending on the nature of the failure, the Trigger LEDS may be
latched in the first number of the test level that failed, the failure code may be flashed out on the LEDs
(if it is the first failed test), or it may make it through the diagnostic, but with the FPP test marked
FAIL. That information will help to isolate which circuitry may be defective and gives the starting point
in troubleshooting a failure. It will be necessary to turn off the 2430 and turn it back on again to repeat
the diagnostic testing from the front panel; however, testing may be done using GPIB diagnostic test
commands.
Testing Method:
Front Panel ILPA13U700 (schematic diagram 3):
4000
FPP
If the system ram data bus, chip selects, or output enable lines are defective, the System ILPwill not
function to run the diagnostics testing. Therefore, if test 3900 fails, the most likely problem is U664
itself. If the diagnostics tests do not run, the Kernel test will have to be used to isolate a system bus or
address decoding problem. An NV RAM failure due to stored data being scrambled requires a "COLD
START" to reload the NV RAM with correct nominal values. The 2430 will need a SELF CAL and an
EXTENDED CAL of the ATTEN, TRIGGERS, and REPET after a COLD START to return it to a com-
pletely calibrated state.
NV RAM A12U664 (schematic diagram 1):
3900
A12U664
Table
6-6
(cont)
Maintenance-2430 Service
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