6-75
If the Front-Panel JLPchecks out ok, turn off the power and remove the jumper connected for the
preceding Front Panel diagnostic test. Turn the 2430 back on and perform the following circuit checks
for any of the Front Panel tests that failed when running the Extended Diagnostics via the GPIB. Use
the circuit checks to isolate the problem in the associated circuitry. IF THE FPP DIAGNOSTICS TEST
FAILED, THE ONLY WAY TO RUN THESE TESTS WILL BE VIA GPIB, AS THE F,RONTPANEL WILL
NOT RESPOND TO BUTTON PRESSES. To gain access to the 2430 via the GPIB when the EXT
DIAG menu is being displayed, a MENU OFF command must be sent to exit extended diagnostics.
3. If the test waveform is not present and the supply voltage, the ground, and the clock are correct,
change the Front-Panel ILP;it is possibly defective.
Figure 6-9. Front Panel ItP diagnostics test.
CH 1 2V
A 51's
5V _T
84ms TO NEXT__
PULSE TRAIN
OV
...___
~
71's
I
71's
I
71's
I---
4917-29
2. Turn the power back on and observe the signal at pin 14. See test waveform illustration of Figure
6-9 for correct waveshape and timing.
1. Turn off power and short pins 1 and 2 of J155 together. (The pins must remain shorted together
during power-on.) This places the Front-Panel JLPin the continuous self-diagnostic mode (Test
4400). Connect a test scope to view the signal present on pin 14 of U700.
Front Panel JLPTest:
4. Perform the Front Panel JLPtest if all the checks in steps 1, 2, and 3 were ok. If not, troubleshoot
any problem area found by the checks.
3. Check pins 8,14,16,17,19,31, and 32 for +5 V and pins 6, 7, and 20 for ground.
2. Check pin 4 for +5 V, pin 1 for ground.
1. Check pin 5 for the 4 MHz clock.
Troubleshooting Front-Panel JLPA13U700:
Table
6-6
(cont)
Maintenance-2430 Service
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